American Chemical Society Research Articles

The Mechanisms and Quality Markers of Anti-rheumatoid Arthritis of Traditional Chinese Medicine.

RA is a recurrent autoimmune disease that has significant adverse effects on the physical and mental health of patients. Traditional Chinese medicine has shown significant advantages in the prevention and treatment of RA. Numerous clinical and experimental studies have confirmed that traditional Chinese medicine components have clear therapeutic effects and minimal adverse reactions in treating RA. The research on traditional Chinese medicine for the prevention and treatment of RA has become a hot topic in the field of autoimmune diseases. The related references about the mechanisms and Q-markers of anti-RA of traditional Chinese medicine in this review were collected from Willy, SpringLink, Web of Science, Elsevier, PubMed, SciFinder, Scopus, ACS publications, Baidu Scholar, Google Scholar, and CNKI. The traditional Chinese medicine components such as terpenoids, flavonoids, and alkaloids have significant anti-RA effects, and their mechanisms are mainly to inhibit NF-κB signaling pathway, inhibit the proliferation of RA fibroblasts like synovial cells, and regulate Th1/Th2 cell balance, and so on. Predicting and studying the Q-markers of traditional Chinese medicine anti-RA by plant phylogeny and chemical componentss, traditional medicinal properties, pharmacokinetics, component measurability, correlation between composition and efficacy, and gut microbiota will provide scientific foundations for the research and further development of anti-RA traditional Chinese medicine. The active components of traditional Chinese medicine exhibited the characteristic of multiple mechanisms in the treatment of RA, such as terpenoids had anti-angiogenesis effects, flavonoids had anti-inflammatory and cartilage protective effects, and alkaloids had antiinflammatory and analgesic effects. The proposal of Q-markers for anti-RA provided new research ideas for promoting the development of new drugs for anti-RA and ensuring the safety and effectiveness of clinical medications.

An Insight into Ethanopharmacology, Phytochemistry, and Pharmacological Properties of Genus Andrographis

Abstract: Andrographis is a member of the family Acantheceae. It contains approximately 44 accepted species. Among them, Andrographis paniculata has been extensively studied during the last decade. The genus contains triterpenoids as the main class of compound, along with carotenoids, flavonoids, glycosides, xanthones, phenolic compounds, and fatty acid compounds. A. paniculata has been reported in Ayurveda, homeopathy, naturopathy, and Siddha. Traditionally, the genus is utilized in treating diarrhea, parasitic problems, liver illness, various skin problems, fever, snake bites, cough and many more. Pharmacological activities like antioxidant, neuroprotective, anti-inflammatory, antimalarial, hepatoprotective, antibacterial antiviral, anticancer, and antidiabetic have been documented in it with scientific evidence. Various components found in this genus show broad biological opportunities for novel medicinal medicines. Andrographolide is the major chemical constituent present in almost all the species. It has been reported for various pharmacological activities, mostly for antioxidant and anticancer. The genus is widely spread among India, China, Southeast Asia, Sri Lanka, Vietnam, Thailand, and basically tropical and subtropical Asia. In India, it is found in Nallamala Hills, Andhra Pradesh, and South India. The present review has provided a critically analyzed vision of phytochemistry, traditional uses, and pharmacological applications of the genus Andrographis. The current information was collected systematically from scientific databases, including Google Scholar, Pub Med, ACS Publications, SciFinder, Science Direct, and Web of Science.

Academic Library Pricing Dataset for SciFinder Scholar, Web of Science, and Scopus: 2018-2024

This dataset contains database pricing and agreements received through public records requests made to members of the Association of Research Libraries (ARL) and a few non-ARL research libraries. Pricing from the years 2018 to 2024, depending on the institution, is included for three premium academic databases: SciFinder from the American Chemical Society’s Chemical Abstract Service, Web of Science from Clarivate, and Scopus from Elsevier. The pricing in this dataset is difficult to acquire and of significant interest to libraries that license these products and those wishing to investigate pricing strategies and approaches in the library database market.

An analogous Twisted Little Tale on the significance of unusual infrared frequencies

AbstractThe autobiographical 2024 Brief Report published in Structural Chemistry by the heterocyclic chemist Professor José Elguero prompted the author to describe his recollections of a similar yet twisted little tale of an incident occurred in 1964 during his Organic Chemistry Ph.D. period at The Hebrew University of Jerusalem. The trait d’union between the two tales is the significance of unusual infrared frequencies in the characterization of newly synthesized organic compounds. The absence of an infrared band at the 1800–1900 cm−1 region was a sufficient condition for ruling out a cyclopropanone structure (Elguero’s little tale). The presence of such an infrared band was a necessary condition for the presence of a triafulvene and triapentafulvalene systems (author’s twisted little tale). The related experience in the publication of Communications to the Editor articles in the Journal of the American Chemical Society is also described. A further teaching of the author’s tale is the importance of early learning of ethics and integrity in the scientific publication process.

Mitigating the Corrosion of Anodized 304 and 316 Stainless Steel with GOx/PEDOT Coating for Bioelectrochemical Saline Water Applications

Steels are the most used alloys worldwide as they have superior mechanical properties, such as ductility and elasticity. Stainless steel (SS) is used far and wide from infrastructure, households, vehicles, surgical equipment, and medical implants, to electrochemical applications such as supercapacitors, fuel cells, lithium-ion batteries, aqueous rechargeable batteries, and bioelectrochemical systems (BES)1 such as microbial fuel cells (MFCs)2 and microbial electrolysis cells (MECs)3. Even though oxidized stainless steel is a very effective electrode material for BES, it has a high risk of corrosion due to the removal of the protective Cr-based passive oxide layer4.Hereby, this research aims to investigate the corrosion behavior of anodized stainless steel (SS) 304 and 316 mesh in saline water for potential use in BES with high salinity and try to mitigate that corrosion behavior using biocompatible materials. The tested electrodes include SS304 and SS316 mesh before and after anodization (anodized SS, AN-SS), in comparison to AN-SS coated with double layers of graphene oxide (GOx) and poly(3,4-ethylenedioxythiophene) (PEDOT). SS 304 and 316 were anodized using selective leaching protocol to enhance the removal of the bioincompatible and insulating Cr-based layer. The removal of that layer makes SS more susceptible to dissolution and hence further protection is needed. Both GOx and PEDOT were selected to enhance the surface conductivity, biocompatibility, and corrosion resistance. GOx was synthesized using the electro-exfoliation of a graphite sheet at a constant voltage of 10.0 V in terephthalic acid + NaOH solution, followed by centrifuging at 3000 rpm to remove the large particles.5 After several cycles of washing, the freeze-dried GOx was mixed with Nafion for ink preparation, which was used to coat the An-SS using the spray coating method. The coated electrode was further covered with a PEDOT layer, using the chronpotentiometry electropolymerization method (2 mA/cm2, for 10, 30, or 60 min). Several characterization techniques such as SEM, EDX, XPS, FT-IT, Raman spectroscopy, XRD, and TEM, were used to characterize the physical and chemical structure of the coating materials and the the fabricated electrodes. The corrosion behavior was evaluated using potentiodynamic and potentiostatic methods. Based on the anodic polarization results, the corrosion, passivation, and breakdown (due to dissolution) regions were identified. In this presentation, the corrosion behavior (Ecorr, Icorr, breakdown potential, etc) of the studied electrodes will be correlated with their chemical and physical structures. References K.-B. Pu, J.-R. Bai, Q.-Y. Chen, and Y.-H. Wang, in Novel Catalyst Materials for Bioelectrochemical Systems: Fundamentals and Applications, ACS Symposium Series., vol. 1342, p. 165–184, American Chemical Society (2020) https://doi.org/10.1021/bk-2020-1342.ch008.A. A. Abbas, H. H. Farrag, E. El-Sawy, and N. K. Allam, Journal of Cleaner Production, 285, 124816 (2021).Y. Zhang, M. D. Merrill, and B. E. Logan, International Journal of Hydrogen Energy, 35, 12020–12028 (2010).P. Ledezma, B. C. Donose, S. Freguia, and J. Keller, Electrochimica Acta, 158, 356–360 (2015).H. S. Wang et al., Green Chem., 20, 1306–1315 (2018).

Enhanced Discharge Capacity in Carbon Felt Electrodes for Aqueous Aluminium-Ion Half-Cells

Diversifying the battery technology in use is an important step in ensuring a sustainable transition to a carbon neutral society, and reducing the emissions associated with lithium-ion cell manufacture. Aluminium is an attractive material for battery applications due to its high theoretical volumetric charge storage capacity of 8046 mA h cm−3 compared to lithium’s 2061 mAh cm-3 and relative abundance in the earth’s crust (1). Aqueous Al-ion batteries are one of many metal-ion systems being investigated utilising water as the electrolyte (2). Further, there are well-established mining, processing, and recycling routes for aluminium, with Li-ion battery recycling still in its infancy (3). Using aqueous electrolytes further provides improved safety as fire risk is reduced, and manufacturing costs are also reduced (4).The substrate on which the electrode material is applied impacts how it is utilised within an electrochemical system. The substrate provides both a shape to the electrode, as well as the material itself forming part of the system, and common substrates double as current collectors e.g. thin metal foils, but carbon polymers have also been explored as a substrate (5, 6). Carbon felt is a conductive substrate, with thin fibres of 5-10 μm diameter, providing a flexible porous structure and large surface area for the active material ‘ ink’ to adhere (0.4 m2 g-1 (7)) . Carbon based electrodes have been assessed in a non-aqueous Al-ion cathodes (8), with varying performance metrics based on the structure and make-up of the electrode, however, these were not investigated as a substrate for further electrode ink. In adding the ink to the carbon felt, the electrode becomes an effective 3D-matrix electrode.This poster explores the use of such 3D-matrix electrodes in order to increase the amount of active material utilised within the aq. Al-ion battery system (9) – a key requirement in reducing the environmental impacts of the battery overall (5), and a means for increasing the capacity of an individual electrode without increasing the overall volume. The cell described in (10) has a carbon-polymer electrode substrate, anatase TiO2 negative electrode and a copper hexacyanoferrate (CuHCF) positive electrode, with the electrolyte being 1 M AlCl3 + 1 M KCl. While the CuHCF redox reaction is partially understood, the negative electrode mechanism has not been fully elucidated. A theorised surface reaction, and pseudo-capacitance of the TiO2 electrode in the aq. Al-ion battery would benefit from an increased surface area of the electrode provided by the carbon felt. Therefore, a key factor in achieving the optimum utilisation of active material is not purely an increase of TiO2 in the electrode, but an increase in the surface area in contact with the electrolyte. Key findings presented show that the lower active material loadings result in a higher discharge capacity for both the positive and negative electrodes, with values reaching an order of magnitude higher than seen for the 2D electrodes studied in the past. For the TiO2 electrode, we see 205.0 mAh g-1 @978 mA g-1 (1.81 mg cm-2 active material loading) and for the CuHCF, 259 mA h g-1 @ 1256.8 mA g-1 (2.5 mg cm-2 active material loading). Elia GA, Kravchyk KV, Kovalenko MV, Chacón J, Holland A, Wills RGA. An overview and prospective on Al and Al-ion battery technologies. Journal of Power Sources. 2021;481:228870. Wu D, Li X, Liu X, Yi J, Acevedo-Peña P, Reguera E, et al. 2022 Roadmap on aqueous batteries. Journal of Physics: Energy. 2022;4(4):041501. Baum ZJ, Bird RE, Yu X, Ma J. Lithium-ion battery recycling─ overview of techniques and trends. ACS Publications; 2022. Chao D, Zhou W, Xie F, Ye C, Li H, Jaroniec M, et al. Roadmap for advanced aqueous batteries: From design of materials to applications. Science Advances. 2020;6:eaba4098. Melzack N. Advancing battery design based on environmental impacts using an aqueous Al-ion cell as a case study. Scientific Reports. 2022;12(1):8911. Holland A, Kimpton H, Cruden A, Wills R. CuHCF as an electrode material in an aqueous dual-ion Al3+/K+ ion battery. Energy Procedia. 2018 d;151:69-73. Sigracell. Speciality Graphites for Energy Storage. 2016. McKerracher RD, Holland A, Cruden A, Wills RGA. Comparison of carbon materials as cathodes for the aluminium-ion battery. Carbon. 2019;144:333-41. Holland A, McKerracher RD, Cruden A, Wills RGA. An aluminium battery operating with an aqueous electrolyte. Journal of Applied Electrochemistry. 2018;48(3):243-50. Melzack N, Wills R, Cruden A. Cleaner Energy Storage: Cradle-to-Gate Life Cycle Assessment of Aluminum-Ion Batteries With an Aqueous Electrolyte. Frontiers in Energy Research. 2021;9(290).

Understanding Reaction Kinetics of Iron Oxide (α- Fe2O3) Reduction with Single Entity Measurements

Emitting minimal amount of CO2 during the production of steel is one of the major challenges that can be overcome by producing iron using electrowinning method. The reaction of interest is at the cathode where the direct reduction of Iron oxide (α-Fe2O3) to iron takes place. In this study, we are investigating the electrochemical conversion of hematite (α-Fe2O3) Nanoparticles to iron in an extremely alkaline medium (50 wt% NaOH) using Single Entity Electrochemistry (SEE).Single Entity Electrochemistry is the study of single atom, molecule or particle colliding with the surface of the electrode usually by diffusion or migration. For these experiments, we are developing alkaline stable carbon-fiber (C)/Nickel (Ni) ultra-microelectrode (UME), prepared using multiple pathways such as plasma-focused ion beam.A spike in current transient during chronoamperometry (CA) experiments is observed when a hematite particle collides stochastically with the UME and gets reduced in the process. Each spike is the reduction event of one hematite nanoparticle to iron. Individual reduction events, that last 0.2-0.3 s and resulting in 0.1-0.2 nC of charge being passed were observed at Ni and C microelectrodes, this shows good agreement with the average particle radius of 100 nm. The shape of the current transient was distinct from previously reported transients for metal deposition at cathode1-3. However, A. Allanore, et.al. model was used to support a mechanism for the direct oxide reduction process at nanoscale particles4.The results presented here illustrate the reaction kinetics and the mode of reduction propagation in a single nano-sized hematite particle in alkaline conditions. The kinetics of hematite reduction in alkaline medium is considerably slow as observed from the slope of current spikes in SEE experiments. Furthermore, considering Allanore’s model, the reduction propagation occurs from the outer surface to the inner core.(1) Luo, L.; White, H. S. Electrogeneration of single nanobubbles at sub-50-nm-radius platinum nanodisk electrodes. Langmuir 2013, 29 (35), 11169-11175.(2) Xiao, X.; Fan, F.-R. F.; Zhou, J.; Bard, A. J. Current transients in single nanoparticle collision events. Journal of the American Chemical Society 2008, 130 (49), 16669-16677.(3) Bard, A. J.; Zhou, H.; Kwon, S. J. Electrochemistry of single nanoparticles via electrocatalytic amplification. Israel Journal of Chemistry 2010, 50 (3), 267-276.(4) Allanore, A.; Lavelaine, H.; Valentin, G.; Birat, J.; Delcroix, P.; Lapicque, F. Observation and modeling of the reduction of hematite particles to metal in alkaline solution by electrolysis. Electrochimica Acta 2010, 55 (12), 4007-4013.

Probing the Structure of the Electrochemical Interface Using in-Situ Surface X-Ray Scattering Techniques

Surface X-ray Scattering (SXS) or Surface X-ray Diffraction (SXRD) using synchrotron radiation is a powerful tool for the study of single crystal metal electrodes in the electrochemical environment. The single crystal surfaces have well defined adsorption sites and this enables fundamental links to be made between the surface atomic structure and the electrochemical response as has been illustrated, for example, in electrocatalysis [1]. As the development of electrochemical surface science progresses, there is a growing need for a comprehensive understanding of the atomic sturcture of electrochemical interface, both of the solid electrode and in the liquid electrolyte. This is because changes in the atomic structure across the interface induced by changes in the electric field can affect the system’s reactivity and stability [2]. These processes can be subtle and do not always involve the direct transfer of charge between electrode and electrolyte. Examples include metal surface relaxation and surface reconstruction, as well as charging of the double layer, which leads to rearrangement of the electrolyte side of the interface [3]. To further extend the fundamental understanding of the electrochemical interface structure, we have been developing resonant surface x-ray diffraction (RSXRD), a technique which combines diffraction with spectroscopy, to investigate the charge distribution in the double layer region. Combining experimental data and first-principles calculations, in-situ RSXRD was used to establish the charge distribution both at the Pt(111) electrode surface and at the Cu(001)-c(2x2)-Br electrode surface [5,6].In this talk results of recent studies of single crystal metal electrodes to probe the liquid side of the interface, particularly the role of cations in the electrochemical double layer, will be presented. The results include a systematic study of the low index Ag(hkl) surfaces to explore the role of the surface atomic geometry in determining the electrolyte layering and an exploration of the role that Cs+ cations play in forming the double layer structures on single crystal Au and Pt electrodes.[1] Y. Gründer and C. A. Lucas, Surface X-ray Diffraction Studies of Single Crystal Electrocatalysts, Nano Energy, 29, 378 (2016)[1] O. M. Magnussen and A. Groß, Toward an Atomic-Scale Understanding of Electrochemical Interface Structure and Dynamics. Journal of the American Chemical Society, 141, 4777 (2019)[2] Y. Gründer and C.A. Lucas, Potential-induced structural deformation at electrode surfaces. Current Opinion in Electrochemistry, 19, 168 (2020)[3] Y. Soldo-Olivier et al., Unraveling the Charge Distribution at the Metal-Electrolyte Interface Coupling in Situ Surface Resonant X-ray Diffraction with Ab Initio Calculations, ACS Catalysis, 12, 2375 (2022)[4] Y. Gründer et al., Charge Reorganization at the Adsorbate covered Electrode Surface probed through in-situ resonant X-ray Diffraction Combined with Ab-initio Modelling, Journal of Physical Chemistry C, 126, 4612 (2022)

Investigating the Role of Mixed Oxides for Oxygen Evolution Reaction on Iridium Oxide Electrocatalysts

Ongoing concerns over anthropogenic emissions, fossil fuel sustainability, and related geopolitical aspects point to an increasing need for cost-effective renewable fuel sources. A promising solution is the generation of hydrogen via the catalytic splitting of water, which can be achieved with the aid of proton exchange membrane (PEM) electrolyzers. Notably, the anode material in current commercially available PEM electrolyzers is typically iridium oxide. Despite its effectiveness in facilitating the oxygen evolution reaction (OER), the use of iridium oxide poses challenges due to the scarcity and high cost associated with this precious metal. As the quest for sustainable energy intensifies, ongoing research explores innovative approaches, such as the incorporation of alternative materials and catalysts, to enhance efficiency while addressing the economic and environmental concerns associated with iridium oxide. Studies have shown that incorporating mixed oxides and switching the supports for iridium oxide catalysts help lower the iridium loading while enhancing the OER performance.1,2 In this study, we investigate a series of different sputtered, mixed iridium oxides (Ta, Ti, Ir). We use a rotating disk electrode system to benchmark the catalytic activity of different loadings of mixed oxides. To measure the intrinsic activity of each catalytic active site, we use a home-built operando UV-Vis system to quantify the populations of surface species as well as track the kinetics of different redox transitions during OER. We incorporate nanoscale secondary ion mass spectrometry to probe the migration of different mixed oxide species before and after electrochemical cycling and use kelvin probe force microscopy to estimate the conductivity through the different films. In this study, we show the importance of cooperative effects between neighboring iridium oxide species and the coordination of iridium that are responsible for enhanced OER performance. These results indicate that doping modulates coverage dependent interactions at the surface, which affects both the binding energetics and populations of rate limiting intermediates. We believe this study will serve as a steppingstone for future designs of more cost-efficient PEM electrolyzers.(1) Oh, Hyung-Suk, et al. "Electrochemical catalyst–support effects and their stabilizing role for IrO x nanoparticle catalysts during the oxygen evolution reaction." Journal of the American Chemical Society 138.38 (2016): 12552-12563.(2) Zheng, Ya-Rong, et al. "Monitoring oxygen production on mass-selected iridium–tantalum oxide electrocatalysts." Nature Energy 7.1 (2022): 55-64.

Ionic 2D Materials

2D materials are an exciting topic with a wide variety of applications in many research fields, from optoelectronics, photonics or qubit devices to catalysis. So far, these layered nanoscopic materials have been obtained by different procedures. In top-down approaches, from simple mechanical "Scotch tape" exfoliation to liquid exfoliation to break the weak non-covalent interactions between layers. In this project, the challenge was to obtain 2D flakes of a 3D ionic starting material with cubic rock salt structure (e.g. alkali halides NaCl, NaF, KCl, KF or CsF). They will have physical properties with substantial differences from those of known 2D materials. For example, there are few large bandgap 2D materials, almost exclusively BN layers. The BN bulk system has a band gap around 4 eV and its monolayer 6 eV, while the employed alkali halides in this project, the bulk vales are 10.0 eV (CsF), 10.9 eV (KF), 11.7 eV (NaF), KCl eV (8.5) and eV NaCl (8.6). This will open many applications that are now only restricted to BN layers. The crucial point is how it is possible to exfoliate an isotropic 3D material with ionic interactions in three spatial directions.(1,2) The intercalation of bromine molecules in CsF was corroborated, many years ago, by X-ray single-crystal diffraction.(1,3, see Figure) The intercalated structure is analogous to that of other conventional 2D materials; for example, graphene also with bromine molecules. This intercalation into the 3D structure of the alkali halide has two effects, one is to generate an anisotropic 2D structure with alternated monoatomic CsF layers and layers of Br2 molecules. The second important effect is that now for the exfoliation of the CsF-Br2 compound, only the non-ionic F···Br-Br interactions must be broken. Preliminary DFT calculations indicate that such contact energies are of the same order of magnitude as other non-covalent interactions of common 2D materials.The intercalation of such 2D materials has been performed by the intercalation of Br2 and IBr molecules combined with different exfoliation techniques (sonication-centrifugation, ball milling, microwaves..). The characterization of the 2D flakes has been performed using Atomic Force Microscopy. The final goal of this project is to make a profit from the large gap of such 2D systems for optoelectronic properties, such as single-photon emission.(1) Desmarteau, D. D.; Grelbig, T.; Hwang, S. H.; Seppelt, K., Angewandte Chemie-International Edition in English 1990, 29 (12), 1448-1449(2) Ruiz, E.; Alvarez, S., Journal of the American Chemical Society 1995, 117 (10), 2877-2883.(3) Drews, T.; Marx, R.; Seppelt, K., Chemistry-a European Journal 1996, 2 (10), 1303-1307. Figure 1

Spatiotemporal Active Phase Evolution for CO2 Electrocatalysis

Transition-metal-based solid-state electrocatalysts undergo dynamic phase transformation governed by the local electrochemical environment during operation, e.g., oxygen evolution/reduction(1,2), hydrogen evolution(3), and carbon dioxide reduction(4). Electrochemical active species, often hidden before operation, can become evolved due to the applied electrochemical potential and/or surrounding chemicals. These species are stabilized under the local environment dynamically generated by the reaction product, e.g., proton (H+) or hydroxyl (OH-) group(5,6).Active species often account for a small fraction (i.e., minor motif) of the entire catalyst volume, and the nanoscale morphology and chemical composition of the electrocatalyst are inhomogeneous and continuously change during the electrochemical reaction. Thus, capturing the active species remains a major challenge. Spatiotemporal observation of the structural/chemical changes of the electrocatalyst and the correlation with the local electrochemical environment may reveal the active species and elucidate the governing step toward their formation. Furthermore, identification of the key intermediate step of catalyst phase transformation allows the redirection of low- to high-active catalysts; however, this remains challenging.During electrochemical CO2 reduction (ECR), (hydr)oxide-derived Cu electrocatalysts experience significant phase transformation and show high activity and selectivity for carbon dimerization (C–C coupling)(7,8,9). The location and chemical composition of the active species evolving during electrochemical phase transformation may be strongly heterogeneous; however, these species have not been clearly determined. Recent studies have employed operando characterization techniques, e.g., fluorescence hard/soft X-ray(4,10), X-ray photoelectron(11), and Raman spectroscopy(6), to elucidate the active species responsible for high C–C coupling activity. However, although these techniques could track the changes in chemical composition of the electrocatalysts during operation, they did not reveal the spatiotemporal evolution of the active species or existence of minor motifs, owing to their inefficient chemical sensitivity. Thus, it is imperative to develop an operando analysis technique that can probe the nanoscopic chemical composition with high spatial/temporal resolution and sufficient detection limit.By observing the chemical and morphological evolution of highly efficient ECR catalysts during operation, we identified the key intermediate species toward highly active surfaces and significantly enhanced the C–C coupling activity. Operando transmission soft X-ray microscopy(1,12,13), which visualizes the nanoscale chemical composition distribution of Cu-based catalysts during ECR, revealed that partially evolved Cu+ phases and surface Cu2+ phases are responsible for the dynamic dissolution–redeposition process(4,8) and improvement of C–C coupling activity, respectively. We further demonstrated that the dissolution–redeposition process is electrochemically triggered by inducing Cu+ phases, which are redirected to copper-carbonate-hydroxide species(6,14,15) even under high cathodic potentials. DFT calculations suggest that these cationic Cu species potentially serve as active species and/or assistive sites for enhancing C–C coupling activity.(1) Mefford, J. T., et al. Nature 593(7857), 67-73 (2021)(2) Kreider, M. E., et al. ACS Applied Materials & Interfaces 11(30), 26863-26871 (2019)(3) Zhai, L., et al. ACS Energy Letters 5(8), 2483-2491 (2020)(4) De Luna, P., et al. Nature Catalysis 1(2), 103-110 (2018)(5) Wang, Y., et al. Nature Catalysis 3(2), 98-106 (2020)(6) Henckel, D. A., et al. ACS Catalysis 11(1), 255-263 (2021)(7) Lee, S. Y., et al. Journal of the American Chemical Society 140(28), 8681-8689 (2018)(8) Zhong, D., et al. Angewandte Chemie International Edition 60(9), 4879-4885 (2021)(9) Lei, Q., et al. Journal of the American Chemical Society 142(9), 4213-4222 (2020)(10) Eilert, A., et al. The Journal of Physical Chemistry Letters 7(8), 1466-1470 (2016)(11) Arán-Ais, R. M., et al. Nature Energy 5(4), 317-325 (2020)(12) Lim, J. et al. Science 353, 566–571 (2016)(13) de Smit, E., et al. Nature 456(7219), 222-225 (2008)(14) Spodaryk, M., et al. Electrochimica Acta 297, 55-60 (2019)(15) Jiang, S., et al. ChemSusChem 15(8), e202102506 (2022) Figure 1

Quantum Chemistry Based Battery Electrochemistry: The Effect of Entropy and Anode Surface Structure

Lithium-sulfur (Li-S) battery is a promising battery technology, thanks to their high energy density and the use of inexpensive materials. A Li-S battery typically consists of a Li anode, a sulfur cathode or sulfur-based catholyte, and an organic solvent for lithium polysulfides (Li2S x ). Upon discharge, Li2S x chains accept Li and undergo successive chain shortening events, with the final discharge product being Li2S. Li2S is however insoluble in typical organic solvents and its irreversible precipitation leads to the impairment of Li-S batteries. The addition of phosphorus pentasulfide (P2S5) to a Li2S x catholyte has been experimentally and theoretically shown to form complexes with sulfur chains, which can accommodate Li2S, thus overcome the problem of Li2S precipitation and improving battery cyclability. [1]Quantum chemistry and specifically density functional theory (DFT) calculations have been used to predict molecular structures and electrochemical potentials for Li-S batteries, as well as other electrochemical systems. Here we present a series of DFT calculations (uB3LYP/6-31+G(2df,p)) using the P2S5-Li2S8 system as a case study to highlight considerations critical to reliable electrochemical predictions. Here, we focus on entropy, atomic structure of metal anode surface sites, and the level of DFT theory.The level of theory used throughout this study (uB3LYP/6-31+G(2df,p)) was chosen after careful comparison with other levels of theory, with varying methods and functionals (HF, B3LYP, M06, M11) and basis sets (3-21G, 6-31G(d), 6-31+G(2df,p), 6-311G(d), 6-311+G(2df,p), cc-pVTZ). The B3LYP functional with the 6-31+G(2df,p) or cc-pVTZ basis set performed best in predicting electrochemical potentials in agreement with the cyclic voltammetry experiments, as well as the nuclear magnetic resonance spectra. In addition, different solvents, all with similar dielectric constants, were considered and the resulting impact on E 0 was found to be negligible.The standard electrochemical potential for a full-cell reaction (E 0) is directly related to the Gibbs free energy of the reaction (ΔG 0): ΔG 0 = –nFE 0, where n is the number of electrons transferred and F is the Faraday constant. Gibbs free energy comprises an electronic energy (E elec), a temperature dependent sensible enthalpy (H sens) and a temperature dependent entropy term (–TS). Often, the sensible enthalpy and entropy terms are neglected and reaction Gibbs free energy is approximated as the difference of electronic energy between products and reactants. Our results for reactions involving lithium polysulfide chains and sulfur chains anchored on phosphorus groups indicate that, even at room temperature, the entropy term has a significant contribution to E 0 (of 0.2-0.3 V). Importantly, without considering this contribution, theoretically predicted electrochemical potentials do not match experimental results from cyclic voltammetry.Additionally, atomic structures of different surface sites impact the evaluation of E 0. Several surface sites, as shown in Fig. 1a, were simulated for the atom to be reacted (shown transparent in Fig. 1a), while keeping the rest of the atoms stationary. The Gibbs free energy of reaction was calculated for each site and its effect on E 0 was compared with that of the standard thermodynamic result for bulk Li(s), as shown in Fig. 1b. We found that as pexted, Li atoms in the ‘lone’ or ‘pair’ configuration react more readily. In the case of the ‘lone’ Li, E 0 increases by 0.35 V.In summary, DFT was used to identify the complexation and reaction mechanisms governing P2S5-Li2S8 catholyte batteries. In the calculation of electrochemical potentials for this system, we identified that special care should be taken to the temperature dependence of Gibbs free energy of reactions, the variation of local surface sites for the metal anode, and the level of DFT theory used. These considerations will aid the understanding of Li-S and other battery chemistry.[1] Wang, P., Kateris, N., Li, B., Zhang, Y., Luo, J., Wang, C., Zhang, Y., Jayaraman, A.S., Hu, X., Wang, H. and Li, W., 2023. High-Performance Lithium–Sulfur Batteries via Molecular Complexation. Journal of the American Chemical Society, 145 (2023) 18865–18876. Figure 1

Nitrogen Doped Graphene Aerogel Inserted By Carbon Black As Novel Catalyst Support for Low Temperature Hydrogen Fuel Cells

Carbon supported Pt nanocatalysts, which are commonly used in hydrogen fuel cells, suffer from Pt degradation and carbon corrosion. That causes the high cost and limited lifetime of the fuel cell1. Developing catalyst support materials with high surface area, high electrical conductivity, stability and good interaction with catalyst is an effective solution to address this issue.To enhance the activity and durability of Pt-based catalysts for hydrogen fuel cells, graphene aerogels (GA) are a prospective material with rich porous 3D-structure, large surface area, high electrical conductivity, and good electrochemical stability. They also can improve the tolerance of catalyst CO poisoning and avoid graphene stacking by integrating 2D sheet structure into 3D aerogel structure2, 3. Some research show that the nitrogen doped on the surface of carbon materials could improve ORR activity and electronic conductivity by changing the local electronic structure as well as providing a stable anchor point for pt nanoparticles to enhance the durability of catalysts4, 5.However, most GAs are made from graphene oxide (GO) produced by Hummers method which may lead to safety and environmental issue due to the usage of highly toxic and corrosive chemicals2, 5. Also, there are few articles on the application of GA in fuel cells. It may be limited by the collapse and loss of pore structure caused by compression in a fuel cell setup.In this work, graphene oxide produced by electrochemical exfoliation (EGO) was used to prepare N-doped graphene aerogel (NGA) via hydrothermal treatment with ammonia solution as nitrogen source. Moreover, NGA was mixed with carbon black (CB) as a hybrid support material that can avoid collapse of the macropore and generate a graphene-carbon network to provide large surface area for Pt nanoparticles and improve the performance of the fuel cell. Figure1 shows preliminary characterization results of NGA and performance of NGA-CB supported Pt catalysts with different content of NGA. Rich macro-mesoporous structure of NGA can be observed in the SEM image (Figure 1 (a)). Pt catalyst with 20% NGA has a maximum power density of 838 mw cm-2 which is a 31% improvement over that of Pt/CB (Figure 1 (b)).In conclusion, this study presents a fast, efficient and environmentally friendly way to synthesize nitrogen doped GA. The introduction of NGA into CB as catalyst supports can improve the electrochemical active surface area and performance of fuel cells due to graphene aerogel's high conductivity and porosity. Besides, it is effective to enhance the utilization of Pt and durability of catalysts. This will help to reduce the cost of fuel cells and facilitate their commercialization in various fields of application.Figure 1 (a) SEM images of dried NGA. (b) Performance of Pt/NGA-CB with various content of NGA compared to Pt/CB catalyst in a hydrogen fuel cell at 60 ℃ with 100% RH. References Liu, J.; Wu, X.; Yang, L.; Wang, F.; Yin, J., Unprotected Pt nanoclusters anchored on ordered mesoporous carbon as an efficient and stable catalyst for oxygen reduction reaction. Electrochimica Acta 2019, 297, 539-544.Sarac Oztuna, F. E.; Barim, S. B.; Bozbag, S. E.; Yu, H.; Aindow, M.; Unal, U.; Erkey, C., Graphene Aerogel Supported Pt Electrocatalysts for Oxygen Reduction Reaction by Supercritical Deposition. Electrochimica Acta 2017, 250, 174-184.Wu, Z.-S.; Yang, S.; Sun, Y.; Parvez, K.; Feng, X.; Müllen, K., 3D Nitrogen-Doped Graphene Aerogel-Supported Fe3O4 Nanoparticles as Efficient Electrocatalysts for the Oxygen Reduction Reaction. Journal of the American Chemical Society 2012, 134 (22), 9082-9085.Li, O. L.; Chiba, S.; Wada, Y.; Panomsuwan, G.; Ishizaki, T., Synthesis of graphitic-N and amino-N in nitrogen-doped carbon via a solution plasma process and exploration of their synergic effect for advanced oxygen reduction reaction. Journal of Materials Chemistry A 2017, 5 (5), 2073-2082.Xie, B.; Zhang, Y.; Zhang, R., Coassembly and high ORR performance of monodisperse Pt nanocrystals with a mesopore-rich nitrogen-doped graphene aerogel. Journal of Materials Chemistry A 2017, 5 (33), 17544-17548 Figure 1

(Invited) In Situ spectroscopy of Electrocatalytic and Photocatalytic Interfaces

We explore various aspects of electrochemistry and photoelectrochemistry using in situ spectroscopy of electrode (metal) and photoelectrode (semiconductor) interfaces in situ under electrochemical working conditions. These spectroscopies include sum frequency generation (SFG), transient reflectance/absorption spectroscopy (TAS/TRS), and surface enhanced Raman spectroscopy (SERS). Using surface enhanced Raman scattering (SERS) spectroscopy, we monitor local electric fields using Stark-shifts of nitrile-functionalized silicon photoelectrodes.6 We also report several spectroscopic methods for monitoring local electric fields (within the double layer), local pH,1 photo-induced surface potential and charge transfer2 at electrode surfaces using surface reporter molecules. The Figure below illustrates two surface reporter molecules for determining the local pH, local surface potential, and charge transfer at electrode and photoelectrode surfaces. We also measured the stacking dependence and Resonant interlayer excitation of monolayer WSe2/MoSe2 heterostructures for photocatalytic energy conversion.3 Using sum frequency generation (SFG) spectroscopy, we measure the voltage dependence of the orientation of D2O molecules at a graphene electrode surface, which is related back to the “stiffness of the ensemble”.4 Using transient absorption spectroscopy (TAS), we measure the lifetime of hot electrons photoexcited in plasmon resonant nanostructures.5 Using transient reflectance spectroscopy (TRS), we measure the photoexcited carrier dynamics in a GaP/TiO2 photoelectrode, as well as the electrostatic field dynamics at this semiconductor-liquid interfaces in situ under various electrochemical potentials.6 Here, the electrostatic fields at the surface of the semiconductor are measured via Franz−Keldysh oscillations (FKO). These spectra reveal that the nanoscale TiO2 protection layer enhances the built-in field and charge separation performance of GaP photoelectrodes.7 1 Wang, Y.Y., et al., Measuring Local pKa and pH Using Surface Enhanced Raman Spectroscopy of 4‐Mercaptobenzoic Acid. Langmuir, DOI:10.1021/acs.langmuir.3c02073 (2023).2 Li, R., et al., SERS Detection of Charge Transfer at Electrochemical Interfaces Using Surface-Bound Ferrocene. The Journal of Physical Chemistry C, 127, 14263 (2023).3 Chen, J., et al., Stacking Independence and Resonant Interlayer Excitation of Monolayer WSe2/MoSe2 Heterostructures for Photocatalytic Energy Conversion. ACS Applied Nano Materials, DOI:10.1021/acsanm.9b01898 (2020).4 Montenegro, A., et al., Field-Dependent Orientation and Free Energy of D2O at an Electrode Surface Observed via SFG Spectroscopy. Journal of Physical Chemistry C, 126, 20831 (2022).5 Wang, Y., et al., In Situ Investigation of Ultrafast Dynamics of Hot Electron-Driven Photocatalysis in Plasmon-Resonant Grating Structures. Journal of the American Chemical Society, 144, 3517 (2022).6 Xu, Z.H., et al., Direct In Situ Measurement of Quantum Efficiencies of Charge Separation and Proton Reduction at TiO2-Protected GaP Photocathodes. Journal of the American Chemical Society, 2860-2869 (2023).7 Wang, Y. and S.B. Cronin, Performance Enhancement of TiO2-encapsulated Photoelectrodes Based on III–V Compound Semiconductors, in Ultrathin Oxide Layers for Solar and Electrocatalytic Systems. 2022, Royal Society of Chemistry. p. 103-134. Figure 1

Woodward-Hoffmann or Hoffmann-Woodward? Cycloadditions and the Transformation of Roald Hoffmann from a "Calculator" to an "Explainer".

On May 1, 1965, Roald Hoffmann and R. B. Woodward published their second joint communication, Selection Rules for Concerted Cycloaddition Reactions, in the Journal of the American Chemical Society. Herein is presented a historical analysis of Woodward and Hoffmann's determination of the mechanism of cycloadditions. This analysis is based on thorough analyses with Roald Hoffmann of his 1964 and 1965 laboratory notebooks and his archived documents and on numerous in-person, video, and email interviews. This historical research pinpoints several seminal moments in chemistry and in the professional career of Hoffmann. For example, now documented is the fact that Woodward and Hoffmann had no anticipation that their collaboration would continue after the publication of their first 1965 communication on electrocyclizations. Also pinpointed is the moment in Hoffmann's professional and intellectual trajectories that he became a full-fledged, equal collaborator with Woodward and Hoffmann's transition from a "calculator" to an "explainer."

Nominations sought for 2026 American Chemical Society National Awards

Nominations sought for 2026 American Chemical Society National Awards

ACS Publications and the ACS Energy and Fuels (ENFL) Division Request Nominations for Two Energy Lectureship Awards

ACS Publications and the ACS Energy and Fuels (ENFL) Division Request Nominations for Two Energy Lectureship Awards

Bibliometric Analysis of Scientific Collaboration in Quantum Dots Literature

The field of quantum dots has grown significantly in recent years. A quantitative and comprehensive analysis of this research domain is essential for understanding current trends and future directions. Given the progress made so far, this work aims to facilitate scientific collaboration in the field of quantum dots through a systematic review of 4,176 scientific articles published in the Web of Science database between 2014 and 2023. The study utilized various bibliometric methods, including year-wise publications, annual growth, relative growth rate, doubling time, citation analysis, authorship pattern, collaborative index, identifying co-authorship and collaboration country, top most bibliographic coupling document, and most cited reference. The study period from 2014-2023 has evinced a mean relative growth rate of 0.84 and a doubling time of 3.89. Secured the topmost publication, 519 (2018), simultaneously with a relative growth rate of 12.43.18%. As predicted by the highest citation rate of 25094, an average citation per paper of 51.74% was produced in 2014. The trend of multi-authored papers has significantly increased to 4187 (97.87%), compared to just 89 (2.31%) single-authored papers. Notably, the degree of collaboration was recorded at 0.12% from 2014 to 2018. Additionally, the highest collaboration coefficient, 17.37, was observed in 2023. China had the highest number of publications during this study period. The USA secured the first position in co-authorships and country collaboration at the international level. In addition, the top bibliographic coupling documents are Lim, 2015 and the most cited reference Murray CB, 1993, Journal of the American Chemical Society, VII5, P8706 2023.

Research on hot spot tracking and development trend of NMR quantum chemical calculation in structure elucidation: A bibliometric analysis

Surging numbers of researches in nuclear magnetic resonance (NMR) quantum chemical calculation in structure elucidation of natural products have appeared in recent years, making it a hot spot. But so far, the effective summarization of the numerous and jumbled body of research is still lacking. In this case, this study seeks to show the research structure of this discipline from a integral and scientific viewpoint utilizing bibliometric analysis approach, which is an effective tool to analyze literature resources based on statistical and mathematical methodologies. Literature related to the NMR quantum chemical calculation in structure elucidation was obtained from Web of Science Core Collection (WOSCC) database. The annual publication, collaboration, hot spots, discipline structure and future development trend were analyzed by bibliometric software (Bibliometrix and VOSviewer). 1620 initial research articles published from 2013 to 2023 in this field were included in the analysis. 2015 is a breaking point. China and India are the countries with most contributions, and Russia Academy of Science is the affiliation with the most output. Journal of Molecular Structure (total publication = 348) is the journal with the most output while Journal of the American Chemical Society (local citation = 4090) is the one with the most citations. Muthu, Sambantham is the author who have most articles and citations. The research could be roughly divided into the calculation parameters, the source and properties of the research targets and theory or method of NMR quantum chemical calculation in structure elucidation based on the keywords analysis. There are numerous illustrations to support that quantum chemical calculation of NMR parameters can be used in structure elucidation, which builds firm cornerstone for this field. Three branches, including research target, basis support and application, have made some achievements, but still have wild development space. In recent years, the keywords “hardness”, “docking”, “surface”, “MEP”, “LUMO” appeared most frequently, demonstrating that more concepts in quantum chemistry as well as methods based on them were introduced in structure elucidation and became hot spots in recent years. These results provided an objective and data-based introduction to the NMR quantum chemical calculation in structure elucidation. It can be observed that growing numbers of quantum chemical theories as well as related methods were introduced in NMR parameters calculation in structure elucidation, making the process more efficient and the results more accurate. However, great efforts still needed to pay to archive more precise structures elucidation and high-throughput error correction.

Progress and Prospects of Microplastic Biodegradation Processes and Mechanisms: A Bibliometric Analysis.

In order to visualize the content and development patterns of microplastic biodegradation research, the American Chemical Society (ACS), Elsevier, Springer Link, and American Society for Microbiology (ASM) were searched for the years 2012-2022 using Citespace and VOSvivewer for bibliometrics and visual analysis. The biodegradation processes and mechanisms of microplastics were reviewed on this basis. The results showed a sharp increase in the number of publications between 2012 and 2022, peaking in 2020-2021, with 62 more publications than the previous decade. The University of Chinese Academy of Sciences (UCAS), Northwest A&F University (NWAFU), and Chinese Academy of Agricultural Sciences (CAAS) are the top three research institutions in this field. Researchers are mainly located in China, The United States of America (USA), and India. Furthermore, the research in this field is primarily concerned with the screening of functional microorganisms, the determination of functional enzymes, and the analysis of microplastic biodegradation processes and mechanisms. These studies have revealed that the existing functional microorganisms for microplastic biodegradation are bacteria, predominantly Proteobacteria and Firmicutes; fungi, mainly Ascomycota; and some intestinal microorganisms. The main enzymes secreted in the process are hydrolase, oxidative, and depolymerization enzymes. Microorganisms degrade microplastics through the processes of colonization, biofilm retention, and bioenzymatic degradation. These studies have elucidated the current status of and problems in the microbial degradation of microplastics, and provide a direction for further research on the degradation process and molecular mechanism of functional microorganisms.