Rapid Conversion Research Articles

Shifting CO2 hydrogenation from producing CO to CH3OH by engineering defect structures of Cu/ZrO2 and Cu/ZnO catalysts

The catalytic performance of supported Cu catalysts in CO2 hydrogenation is structurally dependent; hence, regulating the metal-support interactions, often driven by the redox feature of the metal oxide supports, can potentially improve catalytic performance. In this work, we demonstrate an enhanced strong metal-support interaction (SMSI) and electronic metal-support interaction (EMSI) in Cu/ZrO2 and Cu/ZnO after introducing oxygen vacancies into the catalyst supports, evidenced by more Cu encapsulation by oxide overlayers and electron transfer from the defective supports to Cu after introducing the oxygen vacancies. As a result, the defective Cu/ZrO2 and Cu/ZnO catalysts showed markedly improved MeOH production rather than CO production in the CO2 hydrogenation reaction. The in situ FTIR studies showed that the CO2 molecules preferentially adsorbed and activated into bicarbonate rather than carbonate, followed by a rapid conversion into formate on the defective catalyst. These findings highlight the special effects of defective supports in CO2 activation and conversion and catalyst design and synthesis.

Promoting oxygen reduction kinetics of single Fe sites for robust neutral Zn-air batteries via engineering synergistic Fe nanocluster as proton-feeding center

Constructing highly efficient and cost-effective catalysts for neutral oxygen reduction reaction (ORR) remains extremely challenging due to the sluggish reaction kinetics resulting from the low ionic conductivity and limited OH− concentration in the neutral electrolytes. Herein, we intentionally integrate the atomic Fe-N4 sites and Fe nanoclusters on N-doped multimodally porous carbon (FeSA+NC@NMPC) to achieve coherent optimization of rapid oxygen-containing intermediate conversions and fast water dissociation to provide abundant protons for boosting neutral ORR performance. As expected, the FeSA+NC@NMPC exhibits an excellent half-wave potential of 0.76 V in 0.1 M phosphate buffer solutions, outperforming that of commercial Pt/C (0.73 V). Theoretical calculations reveal the synergistic effect between atomic Fe-N4 sites and Fe nanoclusters, in which the former possess stable O2 adsorption and rapid intermediate conversion, while the latter facilitates fast water dissociation to supply protons for accelerating the proton-coupled electron transfer process. Moreover, the FeSA+NC@NMPC-based neutral zinc-air batteries afford a high open-circuit potential of 1.42 V and outstanding cycling stability at 5 mA cm−2 for 100 h. This work utilizes the advantages of both single sites and clusters of Fe to provide an in-depth understanding of the neutral ORR mechanism and advances the development of related energy storage and conversion technologies.

Tuning the crystalline and electronic structure of ZrO2 via oxygen vacancies and nano-structuring for polysulfides conversion in lithium-sulfur batteries

The recent emergence of tetragonal phases zirconium dioxide (ZrO2) with vacancies has generated significant interest as a highly efficient and stable electrocatalyst with potential applications in trapping polysulfides and facilitating rapid conversion in lithium-sulfur batteries (LSBs). However, the reduction of ZrO2 is challenging, even under strong reducing atmospheres at high temperatures and pressures. Consequently, the limited presence of oxygen vacancies results in insufficient active sites and reaction interfaces, thereby hindering practical implementation. Herein, we successfully introduced abundant oxygen vacancies into ZrO2 at the nanoscale with the help of carbon nanotubes (CNTs-OH) through hydrogen-etching at lower temperatures and pressures. The introduced oxygen vacancies on ZrO2−x/CNTs-OH can effectively rearrange charge distribution, enhance sulfiphilicity and increase active sites, contributing to high ionic and electronic transfer kinetics, strong binding energy and low redox barriers between polysulfides and ZrO2−x. These findings have been experimentally validated and supported by theory calculations. As a result, LSBs assembled with the ZrO2−x/CNTs-OH modified separators demonstrate excellent rate performance, superior cycling stability, and ultra-high sulfur utilization. Especially, at high sulfur loading of 6 mg cm−2, the area capacity is still up to 6.3 mA h cm−2. This work provides valuable insights into the structural and functional optimization of electrocatalysts for batteries.

Ultrafast ESIPT dynamics of 4-methyl-2,6-diformylphenol

We investigate the gas-phase photodynamics associated with the S1 (nπ*), S2 (ππ*) and S3 (nπ*) states of 4-methyl-2,6-diformylphenol using trajectory-based surface hopping dynamics simulations. A rapid internal conversion would populate S1 and S3 upon initiating the trajectories on “bright” S2. This nonadiabatic population behavior would lead to intramolecular proton-transfer tautomerization via three states, where the predominant tautomerization happens via S2. An average timescale of ∼ 44 fs is estimated for the tautomerization. The triplet formation can occur via energetically feasible S1-T3 (at the Franck-Condon geometry of normal tautomer) and S1-T2 (at the S1 equilibrium minimum of proton-transferred tautomer) pathways. Intersystem crossing and the forbidden nature of S1 (nπ*) makes the molecule exhibit weak fluorescence.

Significance of Nonadiabatic Effects on Efficient Triplet Generation in Lumazines.

The photophysics of lumazines leading to triplet formation and the effect of thionation are explored in the presence of near-degenerate electronic states. Wave packet simulations are performed on model potential energy surfaces to understand the nonadiabatic population transfer among close-lying excited states. Ultrafast population transfer among singlets opens up new intersystem crossing channels from the higher states. An increased spin-orbit coupling strength originating from thionation enhances intersystem crossing and populates the higher triplets first. The rapid internal conversion in the triplet manifold eventually brings the molecules to their respective low-lying long-lived triplet state.

Density functional theory study of the isomerization conversion of the cluster ConMoS (n = 1–5)

AbstractTo investigate the isomerization transition of cluster ConMoS (n = 1–5), we employ density functional theory and transition state theory methods in this study. The cluster is optimized at the B3LYP/def2tzvp quantum chemical level. The results reveal eight isomerization reactions for the clusters ConMoS (n = 3, 5). Analyzing the activation energies shows a greater propensity for the isomerization transformation in the forward reaction compared to the reverse reaction. At room temperature, six isomerization transformation processes exhibit rapid conversion to the product configurations. Investigation of the equilibrium constants and application of the Arrhenius formula demonstrate that the cluster isomerization reactions are primarily driven by the forward reactions, with four reactions displaying efficient reactant to product conversion rates. Furthermore, there exists a consistent relationship between the structural complexity of the cluster and the change in entropy value. This study provides theoretical insights into reaction rates and optimization of reaction pathways, facilitating mutual validation and development between experimental and theoretical approaches.

Christianity and The Indigenous Spiritualties of The Igbo People: From Multi-Religiousness to Synculturation

The Igbo people of Nigeria have historically maintained a rich and dynamic spiritual tradition. The advent of Christianity introduced new dimensions to their spiritual landscape, leading to significant shifts in religious beliefs and practices. This study aims to explore the complexities and transformations in the Igbo spiritual landscape following the encounter with Christianity. It seeks to understand how the Igbo people navigate the coexistence of indigenous spirituality and Christian beliefs, and the resultant socio-cultural and religious dynamics. Employing a literature review and historical analysis, this study systematically examines scholarly works and historical records to unravel the complex interplay between Igbo indigenous spirituality and Christianity. The study found that the Igbo's flexibility in spiritual choices facilitated their rapid conversion to Christianity, influenced by practical advantages such as effective medicine, economic benefits, and efficient foreign social structures. However, this transition also entailed a mental shift, marked by the perception of the Christian God's superiority following military defeats against foreigners. The study highlights the intricate interplay between indigenous spiritualities and Christianity within the Igbo context. It underscores the role of practical factors, cultural adaptation, and perceived spiritual efficacy in shaping religious transformations. These findings contribute to a deeper understanding of religious syncretism and the evolving nature of spiritual beliefs in multi-religious societies.

ДОСЛІДЖЕННЯ ДВОНАПРЯМНОГО ПЕРЕТВОРЮВАЧА ПОСТІЙНОЇ НАПРУГИ ДЛЯ ЗАСТОСУВАННЯ В СИСТЕМАХ НАКОПИЧЕННЯ ЕНЕРГІЇ

Electromagnetic processes in a bidirectional DC converter with the possibility of increasing and decreasing output voltage levels using an asymmetric inverter for a battery energy storage system when operating in difficult conditions with a short conversion period and determining its parameters are considered. Bidirectional DC converters are widely used in hybrid energy storage systems and in DC distribution power systems. This non-isolated bidirectional boost-buck converter is designed to control the flow of energy between sources with different voltage levels due to the use of low-voltage batteries in these systems. Thanks to the ability of these converters to quickly redirect electrical energy both in one and the other direction, it became possible not only to charge the battery from stationary sources of electricity, but also to charge the battery during the operation of the generator from the internal combustion engine and regenerative braking. The results of calculations of the prototype of a bidirectional DC converter with a 14 V battery, a 200 V DC bus and an output power of 3500 W are given. A prototype was made to confirm the possibility of rapid energy conversion. Ref. 9, fig. 6. Keywords: electric power storage systems, bidirectional DC voltage converter, fast energy conversion, hybrid electric vehicle.

(Invited) Effect of the Electron-Donating and Electron-Withdrawing Substituent on the Diels-Alder Cycloaddition Reaction of Hemifullerenes with 1,3-Butadiene

In the search for an efficient method to synthesize C60, the dimerization strategy of two C30H12 fragments has been considered (1,2). Scott et. al. (3) have demonstrated that the Diels-Alder cycloaddition reaction in the bay regions of a polycyclic aromatic hydrocarbon (PAH) can occur at low temperatures (below 150ᵒC), they have also shown that the use of nitroethylene as masked-acetylene in a DA reaction over the bay regions of perylene and 7,14-dimesitylbisanthene leads to a rapid conversion of the bay regions of the PAH to new unsubstituted benzene rings (4) .This findings allow us to think that the use of a set of substituents on the C30H12 fragment would be a good strategy to favor the DA reaction of substituted C30H12 fragment with butadiene and reduce the activation energies of the reaction. Our previous calculations showed that the DA reaction of 1,3-butadiene with the rim of the C30H12 fragment might be possible, having an activation energy close to that calculated for the DA reaction with 1,3-butadiene and ethylene (5). In this work a theoretical study of the electronic, thermodynamic and kinetic parameters of the Diels-Alder reaction of butadiene with the rims of the substituted C30H12 fragments (triindenetriphenylene 1 and pentacyclopentacorannulene 2) as well as the aromatization of the obtained adducts was carried out (6).(1) a) Scott, L.T. Angew. Chem. Int. Ed. 2004, 43, 4994.; b) Tsefrikas, V.M.; Scott, L.T. Chem. Rev. 2006, 106, 4868; c) Abdourazak, A.H.; Marcinow, Z.; Sygula, A.; Sygula, R.; Rabideau, P.W. J. Am. Chem. Soc. 1995, 117, 6410.(2) Richaud, A.; López, M.J.; Mojica, M.; Alonso, J. A, Méndez, F. RSC Adv., 2020, 10, 3689.(3) Fort, E.H.; Donovan, P.M.; L. T. Scott, L.T. J. Am. Chem. Soc., 2009, 131, 16006.(4) E. H. Fort, L. T. Scott, Angew. Chem. Int. Ed. 2010, 49, 6626.(5) Mojica, M.; Méndez, F.; Alonso, J.A. Molecules 2013, 18, 2243.(6) Mojica, M.; Méndez, F.; Alonso, J.A. Molecules 2016, 21, 200. Figure 1

Metal Nanoclusters as a Superior Polysulfides Immobilizer toward Highly Stable Lithium-Sulfur Batteries.

Due to their high designability, unique geometric and electronic structures, and surface coordination chemistry, atomically precise metal nanoclusters are an emerging class of functional nanomaterials at the forefront of materials research. However, the current research on metal nanoclusters is mainly fundamental, and their practical applications are still uncharted. The surface binding properties and redox activity of Au24 Pt(PET)18 (PET: phenylethanethiolate, SCH2 CH2 Ph) nanoclusters are herein harnessed as an high-efficiency electrocatalyst for the anchoring and rapid conversion of lithium polysulfides in lithium-sulfur batteries (LSBs). Au24 Pt(PET)18 @G composites are prepared by using the large specific surface area, high porosity, and conductive network of graphene (G) for the construction of battery separator that can inhibit polysulfide shuttle and accelerate electrochemical kinetics. Resultantly, the LSB using a Au24 Pt(PET)18 @G-based separator presents a high reversible specific capacity of 1535.4mA h g-1 for the first cycle at 0.2 A g-1 and a rate capability of 887mA h g-1 at 5 A g-1 . After 1000 cycles at 5 A g-1 , the capacity is 558.5mA h g-1 . This study is a significant step toward the application of metal nanoclusters as optimal electrocatalysts for LSBs and other sustainable energy storage systems.

Detoxification of arsenite by iodide in frozen solution

The oxidation of arsenite (As(III)) to arsenate (As(V)) has received significant attention because it helps mitigate the hazardous and adverse effects of As(III) and subsequently improves the effectiveness of arsenic removal. This study developed an efficient freezing technology for the oxidative transformation of As(III) based on iodide (I−). For a sample containing a very low concentration of 20 μM As(III) and 200 μM I− frozen at −20 °C, approximately 19 μM As(V) was formed after reaction for 0.5 h at pH 3. This rapid conversion has never been achieved in previous studies. However, As(V) was not generated in water at 25 °C. The acceleration of the oxidation of As(III) by I− in ice may be attributed to the freeze-concentration effect. During freezing, all components (i.e., As(III), I−, and protons) are highly concentrated in the ice grain boundary regions, resulting in thermodynamically and kinetically favorable conditions for the redox reaction between As(III) and I−. The efficiency of the oxidation of As(III) using I− increased at high I− concentrations and low pH values. The low freezing temperature (below −20 °C) hindered the oxidative transformation of As(III) by I−. The efficiency of the oxidation of As(III) significantly increased using a fixed initial concentration of I− by subjecting the system to six freezing–melting cycles. The outcomes of this study suggest the possibility of the self-detoxification of As(III) in the natural environment, indicating the potential for developing an eco-friendly method for the treatment of As(III)-contaminated areas in regions with a cold climate. It also demonstrates radical remediation to almost completely remove a very small amount of As(III) that was input in As(III)-contaminated wastewater detoxification, a benchmark that existing methods have been unable to achieve.

“Instant 3D” Angiography: Novel Technique for Rapid Conversion of 2D Angiograms into 3D Stereoscopic Videos

Rotational angiography, often referred to as a "spin", is typically presented in 2D. Since rotational angiograms are composed of images acquired from multiple angles, we took advantage of this property to develop a method for converting any rotational angiogram into a 3 dimensional (3D) video. Our aim was to develop a low cost and easily distributable solution without requiring additional hardware or altering acquisition techniques. Six previously acquired rotational angiograms from our institution were imported using custom-written code and exported as anaglyph (red-cyan) videos. The resulting 3D videos convey anatomical depth that is not apparent from viewing the 2D images alone. Processing time was 1.3±0.6s (mean±SD) per angiogram. The only associated cost was $10 for red-cyan 3D glasses. Using our software, any rotational angiogram with at least 0.3 frames per degree of rotation can be converted into 3D. Our solution is an inexpensive and rapid method for generating stereoscopic videos from existing angiograms. It does not require any additional hardware and is readily deployable in low-resource settings. Because the videos are in anaglyph format, they are viewable on any 2 dimensional (2D) display in the interventional suite or operating room, on a mobile device, or at home.

Impact of Trisulfide on the Structure and Function of Different Antibody Constructs

Trisulfide is a post-translational modification (PTM) commonly found in recombinant antibodies. It has been demonstrated that trisulfide had no impact on the bioactivity of mono-specific antibodies (MsAbs). However, the impact of trisulfide on multi-specific antibodies has not been evaluated. In this study, two mass spectrometric methods were developed for comprehensive trisulfide characterization. The non-reduced peptide mapping method combined with the unique electron activated dissociation (EAD) provided signature fragments for confident trisulfide identification as well as trisulfide quantitation at individual sites. A higher throughput method using Fab mass analysis was also developed and qualified to support routine monitoring of trisulfide during process development. Fab mass analysis features simpler sample preparation and shorter analysis time but provides comparable results to the non-reduced peptide mapping method. In this study, a bi-specific (BsAb) and a tri-specific antibody (TsAb) were compared side-by-side with a MsAb to evaluate the impact of trisulfide on the structure and function of multi-specific antibodies. Results indicated that trisulfide dominantly formed at similar locations across different antibody constructs and had no impact on the size heterogeneity, charge heterogeneity, or bioactivities of any assessed antibodies. Together with the in vitro stability under heat stress (25 °C and 40 °C for up to four weeks) and rapid conversion from trisulfide to disulfide during in vivo circulation, trisulfide could be categorized as a non-critical quality attribute (non-CQA) for antibody products.

New greener approach for the Se-N bond formation

A new greener protocol that includes the rapid and quantitative conversion of diaryl diselenides, bearing an amido function, to corresponding N-substituted benzisoselenazolones by 254 nm wavelength UV lamp irradiation is presented. This free radical Se-N bond formation was utilized for a series of diversified substrates under mild reaction conditions. Carrying out the process in an photochemically inactive solvent like acetonitrile enabled to obtain a quantitative conversion for both N-aliphatic and N-aromatic derivatives.

In-situ decoration of Cu2(OH)3F on BiOBr with exposed (010) facets: Heterojunctions and photo-Fenton-like synergistic promote Cu+/Cu2+ circulation

Among various advanced oxidation processes, coupling photocatalysis and Fenton-like reactions can overcome the inherent drawbacks of the single technology, which is usually used to remove organic contaminants from wastewater. In this paper, Cu2(OH)3F/BiOBr composites with (010) facets exposed surface were prepared by a simple hydrothermal method. The degradation efficiency of tetracycline hydrochloride (TC-HCl) solution with Cu2(OH)3F/BiOBr composite in the photo-Fenton-like system reached 98.8 % within 60 min, and the degradation activity was 4.18 and 2.46 times considerably greater than those of photocatalytic and Fenton-like reactions, respectively. After 5 cycles, the degradation efficiency was still maintained at 89.8 %, demonstrating the exceptional stability of the catalyst. Moreover, based on the characterization of the catalyst, it was found that the high exposure of the crystal plane of the BiOBr material (010) not only speeds up the electron transport between Cu2(OH)3F and BiOBr and improves the rapid conversion of Cu2+ ions, but also slows down the rapid electron-hole recombination. Then the free radicals during the reaction were captured, which found that ·OH, ·O2− and h+ were the main active components in this synergistic degradation system. Finally, the mechanism of Cu2(OH)3F/BiOBr (010) heterojunction photo-Fenton-like synergistic degradation was proposed. This work can provide an effective pathway for the removal of antibiotics from wastewater.

Biochar-based microporous nanosheets-mediated nanoconfinement for high-efficiency reduction of Cr(VI)

Biochar-based materials have been widely used to remove Cr(VI). However, current strategies mainly focus on slow adsorption through electrostatic and functional group properties, ignoring the confinement catalytic fast kinetics caused by inherent porous properties. Herein, we designed a confinement strategy to achieve high-efficiency Cr(VI) reduction by encapsulating the catalytic reaction of Cr(VI) and oxalic acid (OA) in the micropore of PCRN-3–10–2–800. The results showed that the removal rate constant of the PCRN-3–10–2–800/OA system was 14.3 and 146.8 times higher than that of the BC-800/OA system (low porosity) and PCRN-3–10–2–800 alone (adsorption), which was highest removal rate constant in the current reported materials under the same system. The structure-activity relationship indicated that the catalytic activity of Cr(VI) depended on the micropore characteristics of the catalyst. Density functional theory calculations confirmed that nanoscale space could enhance Cr(VI) adsorption and reduce the energy barrier of the rate-determining step. The electron paramagnetic resonance spectrum demonstrated the rapid conversion of Cr(VI) to Cr(III). Furthermore, the PCRN-3–10–2–800/OA system showed good applicability and high efficiency for Cr(VI) removal (nearly 100% in 5 min) in industrial electroplating wastewater treatment. This work first proposes a nanoconfinement-induced heavy metal reduction strategy and guides biochar's universality design in wastewater treatment.

Regulating ion-solvent chemistry enables fast conversion reaction of tellurium electrode for potassium-ion storage

Tellurium (Te) has attracted wide interests as the electrode material of potassium-ion batteries (KIBs) due to its high theoretical capacity and good electronic conductivity, but still faces the issues of polytelluride dissolution in electrolyte and the loss of active Te species. Herein, we propose an ion–solvent complex tunning strategy to allow reversible and fast conversion reaction of Te electrode for K+ storage. The electrolyte of potassium hexafluorophosphate (KPF6) dissolved in dimethoxyethane (DME) enables rapid electrochemically-driven conversion of Te in electrode to in-situ construct amorphous CuxTe upon cycling, which benefits from strong oxidation tendency of K+–PF6−–2DME complex to lose electrons. Moreover, the weak solvation facilitates the formation of a thin solid/electrolyte interphase with the KF-rich inner layer on Te electrode, further enhancing K+ diffusion. In addition, the weak interaction between the potassium polytelluride and K+–PF6−–2DME complex largely inhibits the solubility of polytelluride intermediates. Consequently, the Te-based electrode exhibits a high reversible capacity of 272 mAh/g at 0.05 A/g, excellent rate capability (168 mAh/g at 2.0 A/g), and superior cycling stability. This approach could be extended to other alkali metal–chalcogen batteries (Li–S, Li–Se, Na–S, Na–Se, etc.).

Highly efficient, rapid, and practical conversion of carbohydrate into 5-hydroxymethylfurfural using a continuous-flow reactor with 1-(4-sulfobutyl)-3-methylimidazolium bromide ionic liquid as a catalyst

The application of continuous flow reactors for sustainable chemical research and production has attracted much attention. 5-Hydroxymethylfurfural (5-HMF) has been considered high potential for the production of chemicals and fuels. This work demonstrated the promise of synthesizing 5-HMF with high yield and selectivity using ionic liquids under continuous flow. The effects of temperature, solvent, catalyst activity, catalyst loading, substrate, and large-scale synthesis were investigated to choose the optimal reaction condition. As a result, 1-(4-sulfobutyl)-3-methylimidazolium bromide afforded 5-HMF in the good yield, about 68% in DMSO at 140 °C for 5 min. This approach is not only an eco-friendly pathway but also saves time, which can obtain high efficiency and apply in the large-scale production of 5-HMF from fructose.

Socio-economic impacts of agricultural land conversion: A meta-analysis

Land use change (LUC) is one of the main factors of economic development, and humans have been changing land use for many years. Agricultural land conversion (ALC) is determined as a major process in many developing countries. The aim of this study was to investigate the widespread ALC and its main socio-economic impacts in developing countries during the last 50 years. This study was conducted through a meta-analysis of 56 original articles that identified the main impacts of the ALC from the 19th century onwards in four continents, including Africa, Asia, Europe, and America. The findings of meta-regression showed that spatiotemporal impacts had significant influences on socio-economic impacts, and the most important spatial impacts were related to the continents of America and Asia. In addition, the results of ALC’s rate coefficients in meta-regression indicated that the greatest social impacts were related to crime (2.17%) and the greatest economic impacts were related to endangering households’ revenue (2.98%). Therefore, it is concluded that the rapid conversion of agricultural land to achieve economic development leads to socio-economic impacts, and such economic development cannot be sustainable. Accordingly, it is suggested that the ALC consider such things as planning detailed investigations for the ALC, assessing the value of goods and services provided by agricultural land, monitoring unauthorized ALCs, and imposing fines and taxes on the unplanned ALC. Agricultural land provides important non-market goods and services with good management. Improper conversion of agricultural land to non-agricultural land makes it unproductive and endangered, leading to global warming and climate change.

Recent Advances in Common Transition Metal‐Based Single‐Atom Nanozymes and Their Applications in Pollutant Detection and Degradation

AbstractNanozymes can be used as favorable substitutes for natural enzymes because of their strong catalytic activity and good stability. At the same time, research on single‐atom catalysts (SACs) with isolated metal atoms as active centers is also in full swing, showing excellent performance in a variety of catalytic reactions. With the in‐depth study of SACs, people have a comprehensive understanding of them and put forward the concept of single‐atom nanozymes (SAzymes) by combining nanozymes with SACs. As a new type of nanomaterial, SAzymes have attracted great interest due to their remarkable catalytic activity and rapid energy conversion. However, most applications of SAzymes are mainly in the fields of biomedicine and biosensing, and less research has been done in the field of the environment. Based on the amazing ability of nanozymes to detect and degrade pollutants, SAzymes are also used in the environmental field, and even they will show better capabilities. This review mainly analyses common transition metal‐based SAzymes and describes their applications in the field of environmental pollutants.