Catalytic Active Sites Research Articles

Honeycomb‐Structured IrOx Foam Platelets as the Building Block of Anode Catalyst Layer in PEM Water Electrolyzer

Achieving robust long‐term durability with high catalytic activity at low iridium loading remains one of great challenges for proton exchange membrane water electrolyzer (PEMWE). Herein, we report the low‐temperature synthesis of iridium oxide foam platelets comprising edge‐sharing IrO6 octahedral honeycomb framework, and demonstrate the structural advantages of this material for multilevel tuning of anodic catalyst layer across atomic‐to‐microscopic scales for PEMWE. The integration of IrO6 octahedral honeycomb framework, foam‐like texture and platelet morphology into a single material system assures the generation and exposure of highly active and stable iridium catalytic sites for the oxygen evolution reaction (OER), while facilitating the reduction of both mass transport loss and electronic resistance of catalyst layer. As a proof of concept, the membrane electrode assembly in single‐cell PEMWE based on honeycomb‐structured IrOx foam platelets, with a low iridium loading (~0.3 mgIr/cm2), is demonstrated to exhibit high catalytic activity at ampere‐level current densities and to remain stable for more than 2000 hours.

Core-shell structured carbon nanofiber-supported bristlegrass-like conductive metal‐organic framework Cu3(HHTP)2 nanorod arrays for electrochemical and colorimetric dual-mode detection of dopamine in serum

Dopamine (DA) is a central neurotransmitter that plays a crucial role in human metabolism. Its precise detection is of great importance in disease diagnosis. Compared with single-signal detection methods, colorimetric and electrochemical dual-signal outputs can self-validate the measured data and counteract interference effects, which is expected to provide more reliable detection results. In this paper, carbon nanofiber-supported 3D bristlegrass-like π-conjugated conducting metal–organic frameworks (cMOF) Cu3(HHTP)2 nanorod arrays (Cu3(HHTP)2 NRAs/CNF) catalyst with core–shell structure are synthesized by electrospinning and solvothermal reaction. The obtained catalyst possesses remarkable peroxidase-like activity which can catalyze the colorless 3,3′,5,5′ −tetramethylbenzidine (TMB) to blue oxTMB. The mechanism study showes that ·OH radicals are the main active substances. Meanwhile, the core–shell structure between π-conjugated cMOF and CNF can effectively inhibit the aggregation of Cu3(HHTP)2 nanorods and generate more catalytic active sites, resulting in strong electrocatalytic activity of Cu3(HHTP)2 NRAs/CNF. As a result, a novel dual-mode sensor based on colorimetric and electrochemical are constructed for detecting dopamine (DA) with a good linear relationship ranging from 2.5-60 μM and 0.1–106 μM, and the limit of detection (LOD) are 0.27 μM and 10.1 nM (S/N=3), respectively. This study opens up a new idea for the application of cMOF peroxidase-like enzyme in sensing field.

Facile synthesis of spherical-shaped CeC2–TiO2 nanocomposite electrocatalyst with boosted alkaline OER

Developing noble metal-free multifunctional electrocatalysts to catalyze water oxidation is vital for future renewable energy systems. Herein, through several defect modifications, the CeC2–TiO2 nanocomposite on the strength of enriched oxygen vacancies was successfully fabricated by facile hydrothermal method on SS (stainless steel) substrate, attributed to the conductive ability for fast electron transportation. A well-defined phase growth, vibrational bonding of metal atoms, morphological determination, and elemental composition for synthesized heterostructured electrocatalysts were revealed by XRD, FTIR, TEM, and EDX, respectively. XPS has complied to understand the moderate binding energies of CeC2–TiO2 for OER intermediates, which signifies the strong interactions between electronic states of Ce, C, Ti, and O atoms. With the plentiful catalytic active sites, the resultant CeC2–TiO2 entails low overpotentials of only 169 mV and 108.8 mV/dec Tafel slope to afford 10 mA cm−2 for OER in 1.0 M KOH are tested through cyclic and linear sweep voltammogram measurements, thereby exhibit promising activity in alkaline water electrolysis. EIS measurements revealed a decreased polarization resistance for the composite dominated by the small semicircle diameter, corresponding to the adsorption of intermediates. Finally, observed results strongly recommended that the CeC2–TiO2 catalyst exhibited superior OER performance due to excellent electrical chemical coupling between CeC2 and TiO2.

Tailoring the local catalytic microenvironment of metal centers NH2 groups to enhance the CO2RR performance of Ni based catalysts

Efficient catalytic reduction of the main greenhouse gas CO2 into high value-added chemicals is an important measure to alleviate the greenhouse effect and energy depletion. Metal nitrogen (M-N4) macrocyclic complexes have attracted increasing attention in the field of electrocatalytic CO2 reduction (CO2RR) due to the precise adjustment of the catalytic active site according to the requirements and the flexible modification of the external ligand structure. Nevertheless, the poor activity and low selectivity of reduction products restrict their widespread application in electrocatalytic CO2RR. Herein, a combination of nanoscale and molecular level method has been developed to construct easily obtainable 4NH2-NiPc/NH2-CNT hybrid material, in which amino groups are connected to provide electrons toward the central Ni-N4 site to promote the electrocatalytic CO2RR catalytic activity. As a result, the catalyst 4NH2-NiPc/NH2-CNT mainly produces CO in the electrocatalytic CO2RR, which exhibits a Faradaic efficiency of CO (FECO) higher than 92 % within a wide overpotential range of −0.70 to −0.95 V vs. RHE, and provides excellent stability with a current density of 12 mA cm−2 at −0.80 V vs. RHE. In addition, 4NH2-NiPc/NH2-CNT reaches its maximum FECO value of 96 % at −0.8 V vs. RHE, which is approximately 3.1 times that of the original unmodified NiPc/CNT, demonstrating excellent promotion of electrochemical performance. Similarly, compared to NiPc/CNT without amino modification, the current density of 4NH2-NiPc/NH2-CNT exceeds it by more than twice. The research results indicate that promoting role of electron substituted amino groups in catalysis dispersion and electronic environment coordination. This study proposes a promising strategy of introducing amino groups into molecular catalysts and hybridizing with carbon nanotube to enhance the electrocatalytic conversion of CO2 to deep reduction products.

In situ-grown nitrogen-sulfur co-doped carbon nanotubes encapsulated with FeS particles as cathode materials for zinc-air batteries

Transition metal sulfides as ideal oxygen reduction reaction (ORR) catalysts have great potential to regulate multiple reaction pathways and understand their corresponding internal reaction mechanisms at cathode in zinc-air batteries (ZABS), effectively. This work adopted a facile one-pot synthesis method based on chemical vapor deposition (CVD), which utilizes the synergistic effect of zeolite imidazolium ester skeleton (ZIF-8) and polypyrrole (PPY) to grow nitrogen-sulfur co-doped carbon nanotubes (NS-CNT) in the shape of colonic with a relatively uniform size and encapsulated with FeS nanoparticles as the main active sites. The synthesized purpose catalyst noted as FeS-NS-CNT-900, in which that the FeS nanoparticles were tightly encapsulated in carbon nanotubes, and this special structure ensures that the FeS particles do not detach during the reaction, thus greatly enhancing their electrochemical activity and stability. As expected, the FeS-NS-CNT-900 catalyst exhibited a half-wave potential of 0.877 V which is higher than that of commercial platinum charcoal (0.847 V), at 0.1 mol KOH. More importantly, the formation of abundant FeS catalytic active sites, the optimal conditions for NS-CNT growth, and the covered mechanisms of the enhanced ORR reaction activity of FeS-NS-CNT-900 were thoroughly investigated. Additionally, whileFeS-NS-CNT-900 was used as an air cathode material for the assembly of a zinc-air battery, it exhibited a peak power density and specific capacity of 123 mW cm−2 and 785.81 mA h g−1, respectively, which were significantly better than that of platinum-carbon cathode (92.8 mW cm−2 and 740.4 mA h g−1). And surprisingly, the battery with FeS-NS-CNT-900 cathode exhibited (delivered/showed) a high cycle stability of 260 h at 5 mA cm−2. Conclusively, present work provides a feasible method for in situ growth of sulfur and nitrogen co-doped carbon nanotube encapsulated transition metal sulfide nanoparticle catalysts, which may pave a new avenue for the preparation of high ORR performance air cathode material for ZABS.

Bio-derived mesoporous carbon confinement synthesis of ultra-small α-Fe2O3 nanoparticles as electrocatalysts for overall water splitting

The use of high-surface-area materials in loading α-Fe2O3 nanoparticles presents an intriguing approach to improve the electrocatalytic efficiency of overall water splitting. Nevertheless, the effective management of α-Fe2O3 nanoparticle size to prevent their agglomeration continues to pose a significant challenge. This study used bio-based porous carbon with a specific surface area of 2876 m2/g and a mesoporous ratio of 95 % as a carrier to effectively disperse and inhibit the growth of α-Fe2O3 nanoparticles. The Fe2O3/NSC-30 was synthesized using urea as a precipitant through an ethylene glycol-assisted hydrothermal method accompanied by high-temperature calcination, with the α-Fe2O3 nanoparticle size being approximately 5.5 nm. The synergistic effect between the ultra-small nanoparticles and the mesoporous structure facilitates the effective diffusion of electrolyte and exposes more catalytic active sites. The Fe2O3/NSC-30 exhibited remarkable catalytic performance in the OER and HER, as evidenced by the respective low overpotentials of 270 mV and 250 mV at 20 mA cm−2. Furthermore, when Fe2O3/NSC-30 was utilized in the overall water-splitting reaction, a low cell voltage of 1.70 V was sufficient to achieve a current density of 20 mA cm−2. In this study, a new method was proposed for loading ultra-small nanoparticles onto bio-derived mesoporous carbon for promoting overall water splitting with remarkable efficiency.

A new type of pentagonal structure HgS2 monolayer with abundant active sites and low Gibbs free energy for photocatalytic water splitting

Discovery of new two-dimensional (2D) materials not only has important fundamental research significance but also has promising application prospects. Through systematic structure searching combined with density functional theory calculations and simulations, we predict a new 2D monolayer HgS2 material featuring with a previously unreported type of pentagonal structure with orthorhombic P21212 symmetry. The penta-HgS2 monolayer shows good thermal, thermodynamic, mechanical and dynamic stabilities, exhibiting ferroelastic phase transition with an ultralow switching energy barrier (about 1 meV/atom), high ultimate strength of 12 N/m, moderate indirect band gap of 2.25 eV. In addition, the penta-HgS2 monolayer shows significantly anisotropic carrier mobility with a large anisotropy ratio of 98.5 along the y direction. More importantly, the penta-HgS2 monolayer exhibits abundant catalytic active sites, low Gibbs free energy (ΔGH ranging from 0.656 to 1.687 eV) for hydrogen evolution reactions, excellent solar light absorption capacity (∼105 cm−1) with the solar-to-hydrogen efficiency reaching up to 11.83%. The excellent ultimate tensile ability and the ultralow ferroelastic phase transition energy barrier implies penta-HgS2 monolayer material can be used to manufacture flexible mechanical and nanoelectronic devices. The suitable band edge alignments, ultrahigh carrier mobility anisotropy, high catalytic activity and excellent visible light adsorption performance indicate that penta-HgS2 monolayer is a promising candidate photocatalyst for high-performance photocatalytic water splitting. The present work not only supplements a new member to the 2D pentagonal structure material family, but also points out its promising applications in nanoscale devices and photocatalytic hydrogen productions.

Copolymerization of ethylene and isoprene initiated by metallocene catalyst

In this study, we explore the dynamic nature of metallocene catalysts during ethylene/isoprene E/IP) copolymerization, with a focus on the influence of various reaction parameters. Challenges, why do olefinic catalysts show lower activity and molecular weight (Mw) at higher temperatures and low activity with higher diene content? Firstly, we investigate the observed phenomena of decreased catalyst activity and Mw at elevated temperatures using 1.25 μmole of the metallocene. Notably, a substantial increase in active sites from 30 °C to 40 °C, reaching a peak of 89 %. Surprisingly, further temperature increments lead to a noticeable decline in active sites. At 30 °C, the active site primarily engages in the insertion of IP through 3,4 connections, with no detectable cis-1,4 or trans-1,4 connections, which suggests a lack of stereoselectivity at this temperature. At 40–50°C, cis/trans-1,4 connections and active sites are approaching a higher level. This implies a reduction in chain transfer reactions, making catalytic active sites more favorable to cis/trans-1,4 connections. Secondly, we observe a remarkable impact of IP concentration in the E/IP copolymers, active centers, and activity show stability when the amount of IP was 0.116–0.48 mol/L and then started to decline when the amount of IP 0.96 mol/L, indicating a threshold beyond which deactivation occurs. Increasing IP concentration not only reduces activity and active sites but also fails to reactivate dormant polyethylene sites. The Mw and active centers of copolymers progressively decrease with elevated IP concentration, suggesting a faster chain transfer reaction with IP compared to E.

Ga-doped spinel-typed Co-Al catalysts for CO2-assisted ethane dehydrogenation

A series of Ga-doped spinel-typed Co-Al catalysts were prepared via one-step evaporation-induced self-assembly (EISA) method. These catalysts present promising catalytic performance for CO2-assisted ethane dehydrogenation, which can be ascribed to the conjunction effect of cobalt and gallium species. The incorporation of Ga into the structure of Co-Al spinel has been recognized for enhancing CO2 conversion via reverse water-gas shift reaction, leading to a favorable equilibrium shift towards ethylene, along with an improved catalyst stability as a result of coexisting Boudouard reaction. Through X-ray photoelectron spectroscopy (XPS), X-ray absorption fine structure (XAFS), NH3 and CO2 temperature-programmed desorption (TPD) characterizations, coordinatively unsaturated Co2+ and Ga3+ cations were identified as collaborative catalytic active sites, with gallium species taking the prominent role. These sites were closely associated with the formation of acid-base pairs on the catalyst surface, which were crucial for the adsorption and activation of the reactants.

Efficient H2O2 Synthesis through a Two-Electron Oxygen Reduction Reaction by Electrocatalysts.

The two-electron oxygen reduction reaction (2e-ORR) for the sustainable synthesis of hydrogen peroxide (H2O2) has demonstrated considerable potential for local production of this environmentally friendly chemical oxidant on small, medium, and large scales. This method offers a promising alternative to the energy-intensive anthraquinone approach, placing a primary emphasis on the development of efficient electrocatalysts. Improving the efficiency of electrocatalysts and uncovering their catalytic mechanisms are essential steps in achieving high 2e-ORR activity, selectivity, and stability. This comprehensive review summarizes recent advancements in electrocatalysts for in-situ H2O2 production, providing a detailed overview of the field. In particular, the review delves into the design, fabrication, and investigation of catalytic active sites contributing to H2O2 selectivity. Additionally, it highlights a range of electrocatalysts including pure metals and alloys, transition metal compounds, single-atom catalysts, and carbon-based catalysts for the 2e-ORR pathway. Finally, the review addresses significant challenges and opportunities for efficient H2O2 electrosynthesis, as well as potential future research directions.

Single Site W(0) versus Re(I)‐Dipyridophenazine‐ Based Conjugated Porous Polymer for CO2 Photoreduction

Herein, the synthesis and characterization of two robust tungsten and rhenium carbonyl complexes integrated into an organic polymer (CPP‐Re, CPP‐W) are reported. These polymers are obtained by a Suzuki coupling reaction between the corresponding dibromo metal‐carbonyl substituted dipyrido[3,2‐a:2′,3′‐c]phenazine complex and 1,3,5‐triphenylbenzene‐4′,4″,4″,4‴‐triboronic acid and integrated catalytic active sites and photosensitizer since they have not only nitrogen sites to coordinate metal active centers as rhenium or tungsten but photoactive units with good charge‐separating ability which can significantly improve the CO2 photoreduction reaction (CO2PRR). These polymers show similar activity in solid–gas CO2PRR in absence of sacrificial agents to produce syn gas (CO + H2) but CPP‐W selectivity to products change regarding CPP‐Re being able to produce also large amount of more demanding electron products such as methane and ethane. Moreover, the single‐site Re‐ or W‐CPP catalysts could prevent the dimerization of complexes that produces its deactivation. This work shows the potential of CPPs as matrices to support single active centers for heterogeneous catalysis.

Enhancing the activity of Ni-B catalyst via Cu doping towards hydrogen evolution from NaBH4 hydrolysis

Developing efficient, economical, and eco-friendly catalysts for hydrogen release from hydrogen storage materials such as sodium borohydride (NaBH4) is recognized as an ideal solution to meet the growing demand for clean energy. In the present study the Ni-Cux-B alloy catalysts with different Cu doping content on the corncob (CC) substrate via a facile electroless plating method for the hydrolysis of NaBH4 were synthesized. The structural and morphological characteristics of the synthesized catalysts were investigated using various analytical techniques. The results showed that an appropriate Cu content has a remarkable excitation effect on the catalytic activity of Ni-B. The Cu doping strategy effectively changes the dispersion of metal species and provides more catalytic active sites on the surface of the catalyst. Moreover, the synergistic effect between metals after Cu doping enhances electron transfer and facilitates the adsorption and activation of BH4 and H2O molecules, thereby promoting hydrogen production activity. The optimized Ni-Cu7.2-B catalyst achieved a hydrogen generation rate (HGR) of 1321.56 mL min−1 g−1 in alkaline NaBH4 solution at 303 K, with an activation energy (Ea) of 46.26 kJ mol⁻1. The Ni-Cu7.2-B catalyst exhibits satisfactory stability, retaining 90.8 % of its initial catalytic activity after five cycles.

Some heterocycles connected to substituted piperazine by 1,3,4-oxadiazole linker: Design, synthesis, anticholinesterase and antioxidant activity

AD is a multifactorial neurodegenerative disease that has caused morbidity and mortality on a global scale. Currently, there are only a few drugs used in the treatment of AD. Although many compounds that aim at new targets have reached clinical trials, none have been approved. However, discovering efficient drugs for AD treatment is one of the biggest challenges for pharmaceutical research and requires strong support. In this paper, we aim to design a series of indole, benzothiophene, and thiophene bearing 1,3,4-oxadiazole linker to the piperazine basic center and evaluate for their antioxidant and inhibitory activity against both cholinesterase enzymes. Among the compounds, 6a, 7b, and 8b exhibited moderate cationic radical scavenging activities with IC50 values ranging from 20.39 to 30.10 μM. The inhibitory activity results revealed that compounds 5c (IC50 for AChE = 53.91 μM and for BChE = 55.81 μM) and 6c (IC50 for AChE = 54.42 μM and BChE = 45.82 μM) bearing 2-fluorophenyl piperazine moiety showed both AChE and BChE inhibition with moderate IC50 values. To explore the binding properties of the target compounds into the active site of the enzyme, a molecular docking study was carried out using MOE software. The docking study showed that compound 6c targeted both the catalytic active site (CAS) and the peripheral anionic site (PAS) of AChE/BChE and formed important interactions with key residues. Moreover, theoretical physicochemical properties of the best active compound 6c were calculated by the SwissADME web service. It obeyed Lipinski's rule of five and had high GI absorption (gastrointestinal absorption) and good permeating to the blood-brain barrier (BBB). The compound 6c can be considered a promising compound and provides us directions for further research of anti-AD agent development.

Interfacial engineering for the construction of iron sulfide/boride nanosheets heterostructure bifunctional electrocatalysts for high-efficiency overall water splitting

Iron-based materials have been extensively studied and applied as electrocatalysts. However, the electronic structure of iron itself is not conducive to effectively activating adsorbed intermediates, leading to slower kinetic steps. In this study, a heterogeneous composite catalyst with a nano-sheet array structure consisting of iron boron/sulfide (FeS@Fe2B/IP) was successfully prepared through a two-step process involving boriding and sulfidation of iron plates. The nanosheet array structure provides numerous catalytic active sites, promotes effective contact between electrolytes and catalytic sites, and enhances the apparent reaction rate of the catalyst. Additionally, the heterogeneous interface of FeS/Fe2B plays a crucial role in regulating the electronic structure of the metal Fe site, improving charge transfer rates, and accelerating electrocatalytic reaction kinetics. Ultimately, FeS@Fe2B/IP demonstrates outstanding water splitting performance, with only 177 and 191 mV overpotential providing 10 mA cm−2 toward HER and OER, respectively. Furthermore, it achieves a high current density of 500 mA cm−2 at 473 and 520 mV overpotentials for HER and OER, respectively. In addition to its excellent performance in water splitting applications, a bipolar alkaline cell was constructed using the FeS@Fe2B/IP bifunctional catalyst. This achieved current densities of 10 and 100 mA cm−2 at potentials of 1.63 and 1.75 V. Moreover, the catalytic stability of the FeS@Fe2B/IP system remained consistent for nearly 50 hours at current densities of 10 and 100 mA cm−2. These results confirm that FeS@Fe2B/IP is indeed a high-performance bifunctional electrocatalytic material which can significantly improve energy utilization efficiency in various applications.

Pd Nanoparticles Loaded on Cu Nanoplate Sensor for Ultrasensitive Detection of Dopamine.

The detection of dopamine is of great significance for human health. Herein, Pd nanoparticles were loaded on Cu nanoplates (Pd/Cu NPTs) by a novel liquid phase reduction method. A novel dopamine (DA) electrochemical sensor based on the Pd NPs/Cu/glass carbon electrode (Pd/Cu NPTs/GCE) was constructed. This sensor showed a wide linear range of 0.047 mM to 1.122 mM and a low limit of detection (LOD) of 0.1045 μM (S/N = 3) for DA. The improved performance of this sensor is attributed to the obtained tiny Pd nanoparticles which increase the catalytic active sites and electrochemical active surface areas (ECSAs). Moreover, the larger surface area of two-dimensional Cu nanoplates can load more Pd nanoparticles, which is another reason to improve performance. The Pd/Cu NPTs/GCE sensor also showed a good reproducibility, stability, and excellent anti-interference ability.

The design of molecularly dispersed tungstovanadate catalyst via ionic liquid linkers for oxidative desulfurization

The sulfur removal process in diesel is one of the key technologies to produce clean energy using polyoxometalate (POM)-based catalyst with excellent catalytic active sites. Herein, a molecularly dispersed POM supported catalyst CNT@(C4mim)4VW12O40 (CNT@C4VW12) was designed by introducing imidazole ionic liquids (IL) [C4mim]Br as counterionic linkers for oxidation desulfurization (ODS). For the model oil, 100 % desulfurization rate and product selectivity can be achieved within 30 min, and it can be recycled for 5 times without obviously decrease. Moreover, CNT@C4VW12 also displayed excellent performance in real hydrotreated diesel with a removal rate of 97.4 %. Overall, a stable and molecularly dispersed catalyst was constructed by the cooperative effect of π-π stacking, hydrogen bonding and electrostatic force interaction among the CNT, [C4mim]+ and [VW12O40]4−, which would provide new inspirations for design of heterogeneous catalyst towards excellent ODS process.

Highly Efficient Production of Furfural from Corncob by Barley Hull Biochar-Based Solid Acid in Cyclopentyl Methyl Ether–Water System

Furfural, an important biobased compound, can be synthesized through the chemocatalytic conversion of D-xylose and hemicelluloses from lignocellulose. It has widespread applications in the production of valuable furans, additives, resins, rubbers, synthetic fibers, polymers, plastics, biofuels, and pharmaceuticals. By using barley hulls (BHs) as biobased support, a heterogeneous biochar Sn-NUS-BH catalyst was created to transform corncob into furfural in cyclopentyl methyl ether–H2O. Sn-NUS-BH had a fibrous structure with voids, a large comparative area, and a large pore volume, which resulted in more catalytic active sites. Through the characterization of the physical and chemical properties of Sn-NUS-BH, it was observed that the Sn-NUS-BH had tin dioxide (Lewis acid sites) and a sulfonic acid group (Brønsted acid sites). This chemocatalyst had good thermostability. At 170 °C for 20 min, Sn-NUS-BH (3.6 wt%) was applied to transform 75 g/L of corncob with ZnCl2 (50 mM) to generate furfural (80.5% yield) in cyclopentyl methyl ether–H2O (2:1, v/v). This sustainable catalytic process shows great promise in the transformation of lignocellulose to furfural using biochar-based chemical catalysts.

Gardenin B, A Natural Inhibitor for USP7: In vitro Evaluation and In silico Identification

Background: Ubiquitin-specific protease 7 (USP7) is one of the most widely studied deubiquitin enzymes (DUBs). The protein level of USP7 is highly expressed in a variety of malignant cancers, which suggests that it is a prognostic marker of cancers and a potential drug target for oncotherapy. Objective: The aim of this study was to identify natural and effective USP7 inhibitors, in order to understand the activation of the USP7/p53 pathway by natural inhibitors. Methods: In this study, USP7 enzyme activity screening assay system and p53 luciferase reporter assay system have been applied for the discovery of natural USP7 inhibitors targeting the catalytic active site. Molecular docking and molecular dynamics (MD) simulation revealed the combined mechanism between USP7 with gardenin B. Results: The gardenin B was screened from our home-lab natural products (160 flavonoids) and had cytotoxicity in HCT116 cells (IC50 = 46.28 ± 2.16 μM). Preliminary in vitro studies disclosed its antiproliferative activity and activated p53 signaling pathway in HCT116 cells. We found that the complex formed by gardenin B and 5vsk (Ledock score = -6.86, MM/GBSA score = -53.35) had the optimal binding conformation. Moreover, the MD simulation showed that the π-π interactions between gardenin B with His461 and Phe409, and the hydrogen bonds interaction between gardenin B with Leu406 played an important role in maintaining the close binding of the complexes. Conclusion: In conclusion, gardenin B could be used as a natural product inhibitor of USP7 for further optimized design and development potential.

Comparative electrocatalytic behavior of mesoporous FeP and FeS2 for the hydrogen evolution reaction

FeP nanoparticles and FeS2 nanospheres with mesoporous surface are synthesized, and their performance is compared for the hydrogen evolution reaction under identical electrochemical conditions. The activity-determining characteristics of the electrodes, such as specific and electrochemically active surface area, electrochemical impedance and charge transfer resistance, Tafel slopes, number of catalytic active sites, and turnover frequency (TOF) are studied and correlated to their activity. Because of its larger surface area and reduced charge transfer resistance, the FeS2 showed superior HER performance than the FeP, despite the latter’s higher intrinsic catalytic activity. The electrocatalytic stability of the electrocatalysts are also compared.

Electroreduction of CO2 to HCOOH on 3D-Ag nanosheet array supported on carbon membrane

Regulating local CO2 concentration and pH near the catalytic active sites could induce effective reaction pathways for electroreduction of CO2 to chemicals. Here, a membrane nanofluid reactor for efficient electroreduction of CO2 to formic acid was prepared by constructing high-density active sites of 3D-Ag nanosheet array on the surface and within the pores of carbon membrane (3D-Ag NA/CM). The local microenvironment of CO2 and H+ concentration was controlled by adjusting the pore size, CO2 flow rate, and mass transfer mode. In the flow-through mode, the CO2 was electro-reduced to formic acid with Faraday efficiency of 94% and the partial current density of 35.8 mA/cm2. Both the selectivity and activity were higher than those in flow-by mode. The low local concentration of CO2 in the channel was the key to the high selectivity of formic acid. When CO2 flowed through the membrane nanopores, the high collision frequency of CO2 with catalyst on the pore walls facilitated the electroreduction of CO2. It found that the presence of OV promoted the adsorption of CO2 and reduced the energy barrier for its activation into ∗CHOO. It lays a foundation for the research on optimizing the performance of CO2 electroreduction with nanofluid reactors.