Catalytic Mechanism Research Articles

Approaching Splendid Catalysts for Li-CO2 Battery from the Theory to Practical Designing: A Review.

Lithium carbon dioxide (Li-CO2) batteries, noted for their high discharge voltage of approximately 2.8V and substantial theoretical specific energy of 1876Wh kg-1, represent a promising avenue for new energy sources and CO2 emission reduction. However, the practical application of these batteries faces significant hurdles, particularly at high current densities and over extended cycle lives, due to their complex reaction mechanisms and slow kinetics. This paper delves into the recent advancements in cathode catalysts for Li-CO2 batteries, with a specific focus on the designing philosophy from composition, geometry, and homogeneity of the catalysts to the proper test conditions and real-world application. It surveys the possible catalytic mechanisms, giving readers a brief introduction of how the energy is stored and released as well as the critical exploration of the relationship between material properties and performances. Specifically, optimization and standardization of test conditions for Li-CO2 battery research is highlighted to enhance data comparability, which is also critical to facilitate the practical application of Li-CO2 batteries. This review aims to bring up inspiration from previous work to advance the design of more effective and sustainable cathode catalysts, tailored to meet the practical demands of Li-CO2 batteries.

Identify Regioselective Residues of Ginsenoside Hydrolases by Graph-Based Active Learning from Molecular Dynamics.

Identifying the catalytic regioselectivity of enzymes remains a challenge. Compared to experimental trial-and-error approaches, computational methods like molecular dynamics simulations provide valuable insights into enzyme characteristics. However, the massive data generated by these simulations hinder the extraction of knowledge about enzyme catalytic mechanisms without adequate modeling techniques. Here, we propose a computational framework utilizing graph-based active learning from molecular dynamics to identify the regioselectivity of ginsenoside hydrolases (GHs), which selectively catalyze C6 or C20 positions to obtain rare deglycosylated bioactive compounds from Panax plants. Experimental results reveal that the dynamic-aware graph model can excellently distinguish GH regioselectivity with accuracy as high as 96-98% even when different enzyme-substrate systems exhibit similar dynamic behaviors. The active learning strategy equips our model to work robustly while reducing the reliance on dynamic data, indicating its capacity to mine sufficient knowledge from short multi-replica simulations. Moreover, the model's interpretability identified crucial residues and features associated with regioselectivity. Our findings contribute to the understanding of GH catalytic mechanisms and provide direct assistance for rational design to improve regioselectivity. We presented a general computational framework for modeling enzyme catalytic specificity from simulation data, paving the way for further integration of experimental and computational approaches in enzyme optimization and design.

Promoted Hydrogen Peroxide Production from Pure Water on g-C3N4 with Nitrogen Defects Constructed through Solvent-Precursor Interactions: Exploring a Complex Story in Piezo-Photocatalysis.

Hydrogen peroxide (H2O2) production via oxygen (O2) reduction reaction (ORR) in pure water (H2O) through graphitic carbon nitrides (g-C3N4)-based piezo-photocatalysts is an exciting approach in many current studies. However, the low Lewis-acid properties of g-C3N4 limited the catalytic performance because of the low O2 adsorption efficacy. To overcome this challenge, the interaction of g-C3N4 precursors with various solvents are utilized to synthesize g-C3N4, possessing multiple nitrogen-vacant species via thermal shocking polymerization. These results suggest that the lack of nitrogen in g-C3N4 and the incident introduction of oxygen-functional groups enhance the Lewis acid-base interactions and polarize the g-C3N4 lattices, leading to the enormous enhancement. Furthermore, the catalytic mechanisms are thoroughly studied, with the formation of H2O2 proceeding via radical and water oxidation pathways, in which the roles of light and ultrasound are carefully investigated. Thus, these findings not only reinforce the potential view of metal-free photocatalysts, accelerating the understanding of g-C3N4 working principles to generate H2O2 based on the oxygen reduction and water oxidation reactions, but also propose a facile one-step way for fabricating highly efficient and scalable photocatalysts to produce H2O2 without using sacrificial agents, pushing the practical application of in situ solar H2O2 toward real-world scenarios.

Acid-base neutralization strategy for immobilization amino acid ionic liquid within sulfonic acid-based COF as a switch for selective conversion of epoxides

Covalent organic frameworks (COFs) and ionic liquids (ILs) as raw materials exhibit effective catalytic performance and adsorption capabilities in the reaction of epoxides and atmospheric CO2, respectively. Nonetheless, bonding modes between ILs and COFs have restricted their utility, thereby constraining the in-depth study of synergistic catalytic mechanisms over these composite catalysts. Herein, a heterogeneous composite ([DBUH]2Cys@COF-X) were successfully prepared by the facile acid-base neutralization method, incorporating varying amounts of amino acid ILs ([DBUH]2Cys) into the pore channels of sulfonic acid-based COF (TpPa-SO3H). [DBUH]2Cys@COF-3 efficiently catalyzed epichlorohydrin with a yield of 96.38 % without any solvent or co-catalyst under atmospheric CO2. Notably, larger sterically hindered epoxides were selectively blocked on the surface of [DBUH]2Cys@COF-3, enabling [DBUH]2Cys@COF-3 to act as a gatekeeper for selectively catalyzing small sterically hindered epoxides due to [DBUH]2Cys was distributed within the pore channels of [DBUH]2Cys@COF-3. Through DFT calculations, comprehensive understanding of the synergistic activation conferred of -COO- and [DBUH]+ towards CO2 and epoxides in [DBUH]2Cys@COF-3 and the ring-opening mechanism was clarified. This work presents a fresh outlook on the catalyst design by the facile acid-base neutralization method for efficiently catalyzing small-hindered epoxides under atmospheric CO2.

Unleashing the Potential of Single-Atom Nanozymes: Catalysts for the Future.

Single-atom nanozymes (SANs) have become a breakthrough in atomically precise catalysis, which relies on the catalytic active site formed by the single-atom itself. From this angle, SANs and their advantages compared to natural enzymes as well as spaces for their application are emphasized. The SANs have outstanding control over their catalytic activities; this is compared with bulk materials and natural enzymes. The structure of the SANs has very promising potential for the next generation of biosensing and biomedical devices and environmental remediation. Although their capabilities are high, difficulties still arise. The specificity, scalability, biosafety, and catalysis mechanisms raise additional issues that require further research. We build up a vision of the perspectives of the better implementation of SANs, which are designed for diagnostic purposes, improving industrial technologies, and creating new sustainable technologies in the food processing industry. AI and machine learning systems may clarify the structure-performance relationship of SANs for improved material and process selectivity. The future of SANs is very promising, and by addressing these challenges and leveraging advancements in artificial intelligence and materials science, SANs have the potential to become powerful tools for a sustainable future.

Ultrasensitive detection of mycotoxins using a novel single-Atom, CRISPR/Cas12a-Based nanozymatic colorimetric biosensor

Aflatoxin B1 (AFB1) is a typical mycotoxin in cereals, posing a significant threat to the ecology and public health. Overall, the development of nanozymatic sensors with good specificity, high sensitivity, and a clear catalytic mechanism seems to be a challenge for CRISPR/Cas detection of non-nucleic acid targets. In this study, a series of Fe-N-C single-atom enzymes (SAzymes) and Fe-Co magnetic nanoparticles (MNPs) were synthesized via pyrolysis. Fe-N-C SAzymes with high peroxidase-mimetic activity were successfully utilized as TMB chromogenic catalysts for detecting AFB1 via the CRISPR/Cas12a colorimetric aptamer sensor. In the absence of the AFB1 target, its aptamer bound to crRNA and activated the trans-cleavage activity of Cas12a, indiscriminately cutting single-stranded DNA and releasing significant amounts of Fe-N-C SAzymes into the supernatant, which catalyzed the change of TMB to blue. The synthesized Fe-Co MNPs not only effectively reduced the background signal but also significantly reduced the assay cost. This study combined SAzymes with CRISPR/Cas12a technology for the first time for non-nucleic acid target detection. The combination of Fe-N-C SAzymes’ high catalytic activity and stability, and the CRISPR/Cas12a system’s high specificity and signal amplification, significantly improved the detection system’s sensitivity and specificity, enabling the detection of other targets by substituting the aptamers. Additionally, the potential active sites and catalytic mechanism of Fe-N-C SAzymes were investigated using extended X-ray absorption fine structure (EXAFS) spectroscopy and density functional theory (DFT) simulations. This scheme provides a general method for constructing high-density Fe-N-C SAzymes and offers both experimental and theoretical guidance for understanding their catalytic mechanism.

Designing Fe8-N2 Catalytic Sites of Nitrogen-Doped Iron-Based Nanoparticles with Oxidase-Like Activity: Characterization, Calculation and Application.

Designing metal nanoparticles with oxidase-mimicking capabilities has garnered significant attention due to their promising attributes. However, understanding the intricate catalytic mechanisms underlying these nanoparticles poses a formidable challenge. In this study, a straightforward pyrolysis procedure was employed to synthesize nitrogen-doped iron-based nanoparticles (Fe NPs-N@C) with Fe8-N2 serving as active sites. The confirmation of these sites was thoroughly confirmed through density functional theory (DFT) calculations complemented by experimental validation. The resulting Fe NPs-N@C nanoparticles, averaging 5.45 nm in size, exhibited excellent oxidase-mimicking activity, with vmax=1.11×10-7 M s-1and km=1.67 mM, employing 3,3',5,5'-tetramethylbenzidine as a substrate. The oxidation pathway and catalytic mechanism of Fe NPs-N@C involved 1O2⋅ radicals, validated through electron paramagnetic resonance analysis and DFT calculations. Furthermore, Fe NPs-N@C/TMB system was devised for ascorbic acid and nitrite quantitative detection. This method demonstrated the capability to detect ascorbic acid within concentrations ranging from 1 to 55 μM, with a limit of detection (LOD) of 0.81 μM, and nitrite within concentrations from 1 to 160 μM, with a LOD value of 0.45 μM. These findings offer a comprehensive understanding of the catalytic mechanisms of Fe NPs-N@C nanoparticles at the atomic level, along with its potential for colorimetric sensor in future.

Photo-Fenton Degradation of Tetracycline and Photoelectrochemical Properties of ZnFe2O4@ZnWO4 Heterostructure Composite Coupling.

Problems such as bacterial resistance caused by tetracycline antibiotics pose a serious threat to human production and life and ecosystems. We prepared ZnFe2O4@ZnWO4 heterojunction nanocomposites using hydrothermal and coprecipitation methods. The micromorphology, structure, and photoelectrochemical properties were analyzed. In combination with the presence of H2O2, the photo-Fenton activity of the antibiotic tetracycline at high concentration was tested under visible light irradiation, and its catalytic mechanism was investigated. The results showed that the composition of the composite heterojunction improved the catalytic activity of the catalyst. At a pollutant concentration of 50 mg L-1 and pH 5, 30% ZnWO4/ZnFe2O4 degraded 92.1% of tetracycline in 60 min with a degradation rate of 0.0295 min-1, which was 6.7 times higher than that of pure ZnFe2O4. The results of free radical trapping experiments and electron spin resonance techniques indicated that hydroxyl radical (•OH) and superoxide radical (O2-) played important roles in the photo-Fenton degradation of tetracycline. Notably, the catalyst maintained a high degradation rate (80%) after five cycles. ZnFe2O4 introduced in this article may provide a promising strategy for achieving strong light absorption and is authoritative in meeting future environmental requirements.

Theoretical Investigation of Propylene Epoxidation Using H2 and O2 Over Titanosilicate-Supported Au Catalysts

Titanosilicate-supported Au-cluster catalysts can be used to selectively synthesize propylene oxide from propylene using O2 and H2. However, the details of the catalytic reaction mechanism have not yet been elucidated. Thus, the reaction mechanism was investigated using density functional theory calculations. The calculation results revealed that active Ti-OOH forms on the surface Ti site, which is active as an oxidant and acts as an anchorage site for Au nanoclusters. The rate-determining step of propylene oxide synthesis on Au/titanosilicate is O insertion into propylene, with an activation energy of 1.37 eV. The propylene involved in this reaction is activated by adsorption on Au nanoclusters. Moreover, it was also found that the formation of Ti-OOH on Au/titanosilicate requires an activation energy of 0.48 eV, while it is barrierless on Au/anatase-TiO2. However, the decomposition energy of Ti-OOH on Au/titanosilicate is −0.16 eV, which is smaller than that on Au/anatase-TiO2 (−1.12 eV). The results indicate that Ti-OOH decomposes more readily on Au/titanosilicate than on Au/anatase-TiO2 but is easily regenerated because the reaction energy is significantly smaller than that on Au/anatase-TiO2. Therefore, these calculations are qualitatively in good agreement with the experimental results for Au/titanosilicate, which exhibited high catalytic activity at high temperatures.Graphical

Enhanced Fenton Degradation of Tetracycline over Cerium-Doped MIL88-A/g-C3N4: Catalytic Performance and Mechanism.

Since enormous amounts of antibiotics are consumed daily by millions of patients all over the world, tons of pharmaceutical residuals reach aquatic bodies. Accordingly, our study adopted the Fenton catalytic degradation approach to conquer such detrimental pollutants. (Ce0.33Fe) MIL-88A was fabricated by the hydrothermal method; then, it was supported on the surface of g-C3N4 sheets using the post-synthetic approach to yield a heterogeneous Fenton-like (Ce0.33Fe) MIL-88A/10%g-C3N4 catalyst for degrading the tetracycline hydrochloride drug. The physicochemical characteristics of the catalyst were analyzed using FT-IR, SEM-EDX, XRD, BET, SEM, and XPS. The pH level, the H2O2 concentration, the reaction temperature, the catalyst dose, and the initial TC concentration were all examined as influencing factors of TC degradation efficiency. Approximately 92.44% of the TC was degraded within 100 min under optimal conditions: pH = 7, catalyst dosage = 0.01 g, H2O2 concentration = 100 mg/L, temperature = 25 °C, and TC concentration = 50 mg/L. It is noteworthy that the practical outcomes revealed how the Fenton-like process and adsorption work together. The degradation data were well-inspected by first-order and second-order models to define the reaction rate. The synergistic interaction between the (Ce0.33Fe) MIL-88A/10%g-C3N4 components produces a continuous redox cycle of two active metal species and the electron-rich source of g-C3N4. The quenching test demonstrates that •OH is the primary active species for degrading TC in the H2O2-(Ce0.33Fe) MIL-88A/10%g-C3N4 system. The GC-MS spectrum elucidates the yielded intermediates from degrading the TC molecules.

Effects of Clinical Mutations in the Second Coordination Sphere and Remote Regions on the Catalytic Mechanism of Non-Heme Fe(II)/2-Oxoglutarate-Dependent Aspartyl Hydroxylase AspH.

Aspartyl/asparaginyl hydroxylase (AspH) catalyzes the post-translational hydroxylations of vital human proteins, playing an essential role in maintaining their biological functions. Single-point mutations in the Second Coordination Sphere (SCS) and long-range (LR) residues of AspH have been linked to pathological conditions such as the ophthalmologic condition Traboulsi syndrome and chronic kidney disease (CKD). Although the clinical impacts of these mutations are established, there is a critical knowledge gap regarding their specific atomistic effects on the catalytic mechanism of AspH. In this study, we report integrated computational investigations on the potential mechanistic implications of four mutant forms of human AspH with clinical importance: R735W, R735Q, R688Q, and G434V. All the mutant forms exhibited altered binding interactions with the co-substrate 2-oxoglutarate (2OG) and the main substrate in the ferric-superoxo and ferryl complexes, which are critical for catalysis, compared to the wild-type (WT). Importantly, the mutations strongly influence the energetics of the frontier molecular orbitals (FMOs) and, thereby, the activation energies for the hydrogen atom transfer (HAT) step compared to the WT AspH. Insights from our study can contribute to enzyme engineering and the development of selective modulators for WT and mutants of AspH, ultimately aiding in treating cancers, Traboulsi syndrome and, CKD.

WOx-Carbon nanorods catalyzed photoelectrochemical hydrogen evolution reaction of silicon-photocathode in acidic media

Silicon (Si) photocathode with surface decoration of co-catalysts is a promising material for green hydrogen production. The surface of the Si is often further etched into pyramids for optical absorption. However, the photon-generated charges tend to concentrate on the pyramid peaks, whilst the catalyst of nanoparticles generally aggregate in the valley, where less charges are available. In this work, one-dimensional tungsten oxide (WOx) with an ultra-thin layer of carbon species have been used as the cocatalyst, which preferentially stay on the upperpart of the pyramids with intimate contact. WOx has great potential in catalysis for hydrogen evolution reaction (HER) due to its ideal proton adsorption/desorption behavior. However, WOx, especially in form of nanorods, has rarely been reported as cocatalysts for photo(electro)catalysis, due to the challenges in the preparation and stabilities during long-term HER catalysis. Herein, the formation of WOx-C nanorods was induced, leading to improved conductivity and stability as co-catalysts. The density functional theory (DFT) calculations revealed the low reaction free energy of WOx-C co-catalysts and the smooth electrons transfer from W to protons. The Si photocathodes deposited with the optimized WOx-C hybrids nanorods showed high performance in PEC reaction, achieving a current density of −21.3 mA·cm−2 at 0 VRHE and an onset potential of +0.218 VRHE under acidic conditions. The catalytic mechanism of WOx-C nanorods for the pyramidal Si-photocathode is investigated and proposed.

Engineered digestate-derived biochar mediated peroxymonosulfate activation for oxytetracycline removal in sustainable wastewater remediation

Nowadays, biochar is extensively used in wastewater remediation with the aim of achieving water security and circularity with minimal impacts on ecosystems and the environment. In this study, digestate biochar was prepared and modified using different methods and then employed as a peroxymonosulfate (PMS) activator to oxidize oxytetracycline, a model antibiotic pollutant in wastewater. The optimal biochar catalyst was characterized, spin trapping tests were carried out to confirm the dominant catalytic mechanism, and in silico toxicity prediction was conducted based on structure-activity relationships. Assessment of the catalytic performance of the pristine and engineered biochar showed that nitrogen doping increased oxytetracycline degradation efficiency by 1.92-fold (i.e., 100% oxytetracycline degradation with the engineered biochar compared to 52% with pristine biochar), while pyrrolic nitrogen was identified as a major PMS activation site. It was discovered that several parameters, such as catalyst dose, pH, PMS concentration, and competing ions, affected oxytetracycline degradation efficiencies. Additionally, the toxicity of the degradation intermediate was studied. Scavenger trapping tests showed that 1O2 and SO4•- were the most prevalent species during oxytetracycline degradation in the system, with four possible degradation pathways proposed, including secondary alcohol oxidation, hydroxylation, dehydration, and deamidation. Overall, it is anticipated that this study would contribute to our understanding of metal-free biochar activation of PMS as an attractive treatment scheme for antibiotic-polluted water.

Catalytic coal gasification: mechanism, kinetics, and reactor model

Catalytic coal gasification is a promising technology in the field of clean coal utilization. A comprehensive understanding of mechanisms, reaction kinetic, and reactor model is crucial. This article summarizes and analyzes the catalytic mechanisms of key reactions, such as C–O2, C–CO2, C–H2O, and CO–H2. It also compares various kinetic models, including shrinking core model, random pore model, volume model and their respective modifications. Additionally, the article delves into mathematical modellings of catalytic coal gasification, encompassing molecular models or density functional theory, empirical model, computational fluid dynamics, Aspen modeling, and artificial neural network. The aim is to provide a roadmap for the development and scale up of reactors used in catalytic coal gasification.

Functional Diversity and Engineering of the Adenylation Domains in Nonribosomal Peptide Synthetases.

Nonribosomal peptides (NRPs) are biosynthesized by nonribosomal peptide synthetases (NRPSs) and are widely distributed in both terrestrial and marine organisms. Many NRPs and their analogs are biologically active and serve as therapeutic agents. The adenylation (A) domain is a key catalytic domain that primarily controls the sequence of a product during the assembling of NRPs and thus plays a predominant role in the structural diversity of NRPs. Engineering of the A domain to alter substrate specificity is a potential strategy for obtaining novel NRPs for pharmaceutical studies. On the basis of introducing the catalytic mechanism and multiple functions of the A domains, this article systematically describes several representative NRPS engineering strategies targeting the A domain, including mutagenesis of substrate-specificity codes, substitution of condensation-adenylation bidomains, the entire A domain or its subdomains, domain insertion, and whole-module rearrangements.

Fabrication of Pd NCs@GO(Fe3O4) as a magnetically separable and reusable catalyst for catalytic conversion of three types of pollutants from water resources

In recent years, organic contaminants have become so detrimental to both the environment and human health that it is imperative to remove them from water. In this study, Magnetic Pd NCs@GO(Fe3O4) composite microspheres were successfully synthesized, which graphene oxide (GO) was encapsulated with Fe3O4 microspheres serving as the core, and subsequently, palladium nanocubes were deposited in situ onto the GO layer. The samples were thoroughly characterized using XRD, TEM, EDS, FT-IR, Raman, XPS, UV-Vis, VSM, DLS NMR and Zeta techniques. At room temperature, the presence of KBH4 effectively reduced 4-nitrophenol (4-NP), 4-nitroaniline (4-NA), and Congo red (CR). Specifically, 4-NP was fully reduced in three minutes with a TOF of up to 464 min⁻¹; 4-NA was completely reduced in seven minutes, achieving a TOF of up to 280 min⁻¹; And CR was fully reduced in eight minutes, yielding a high TOF of 74.86 min⁻¹. Furthermore, the magnetic Pd NCs@GO(Fe3O4) composite microsphere catalyst demonstrated excellent recovery and high conversion rates after five consecutive cycles, maintaining a minimum value of over 90 %. The reaction rate constants for the catalysts were found to be K4-NP = 1.12 min⁻¹, K4-NA = 0.606 min⁻¹, and KCR = 0.394 min⁻¹, respectively. The underlying catalytic mechanism was also discussed. Overall, this study presents a rapid and environmentally friendly method for synthesizing magnetic noble metal nanocatalysts for the efficient reduction of Congo red (CR), 4-nitroaniline (4-NA), and 4-nitrophenol (4-NP).

Exploring the influence of external electric fields on the catalytic pyrolysis of oil shale kerogen molecules

Oil shale is a widely distributed and abundant sedimentary rock that can be converted into shale oil through pyrolysis, providing a supplementary solution to the increasing scarcity of conventional fossil energy. However, the traditional pyrolysis process of oil shale faces problems such as low oil yield, high energy consumption, and poor oil quality. Recent experiments have demonstrated that using an external electric field to catalyze the pyrolysis of oil shale can address these problems. However, due to the complex physical and chemical properties of oil shale and its pyrolysis process, the catalytic mechanisms and effects have not been reasonably explained. To address these issues, this study uses density functional theory to calculate the properties of oil shale molecules under external electric fields of different directions and strengths. The results indicate that at electric field strengths far exceeding experimental conditions, the external electric field does have a certain catalytic effect on oil shale, which varies depending on the molecule. However, at electric field strengths achievable in actual laboratory conditions, the catalytic effect of the electric field on oil shale is not significant. Therefore, the mechanisms revealed by past experiments on the catalytic effects of electric fields on oil shale pyrolysis may be partially flawed. This study not only fills the gap in understanding the mechanisms of external electric field catalysis of oil shale but also provides a theoretical foundation for future applications of electric fields in catalyzing oil shale.

Ruthenium-Based Electrocatalysts for Hydrogen Evolution Reaction: from Nanoparticles to Single Atoms.

Benefiting from similar hydrogen bonding energy to Pt and much lower price compare with Pt, Ru based catalysts are promising candidates for electrocatalytic hydrogen evolution reaction (HER). The catalytic activity of Ru nanoparticles can be enhanced through improving their dispersion by using different supports, and the strong metal supports interaction can further regulate their catalytic performance. In addition, single-atom catalysts (SACs) with almost 100% atomic utilization attract great attention and the coordinative atmosphere of single atoms can be adjusted by supports. Moreover, the syngenetic effects of nanoparticles and single atoms can further improve the catalytic performance of Ru based catalysts. In this review, the progress of Ru based HER electrocatalysts are summarized according to their existing forms, including nanoparticles (NPs), single atoms (SAs) and the combination of both NPs and SAs. The common supports such as carbon materials, metal oxides, metal phosphides and metal sulfides are classified to clarify the metal supports interaction and coordinative atmosphere of Ru active centers. Especially, the possible catalytic mechanisms and the reasons for the improved catalytic performance are discussed from both experimental results and theoretical calculations. Finally, some challenges and opportunities are prospected to facilitate the development of Ru based catalysts for HER.

Coupling interface, electronic and conjugation effects in C-COFs/TiO2 composite structure toward boosting photocatalytic hydrogen evolution

Hydrogen energy, recognized as a pivotal clean energy source, has attracted considerable attention in the realm of photocatalytic hydrogen production. Nevertheless, inorganic materials were difficult to regulate band gaps, resulting in limited photogenerated carrier rates. Additionally, organic materials frequently suffer from insufficient stability and a propensity for electron recombination. Therefore, fully utilizing the interface effect will become an important breakthrough for novel and efficient catalysts. Herein, hydroxylate covalent organic frameworks (H-COFs) were formed by direct synthesis method, in addition, titanium dioxide (TiO2) was used as an inorganic substrate, and TiO2 was transformed titanium acid under weakly acidic conditions, meanwhile, chloride covalent organic frameworks (C-COFs) growth on TiO2 surface by interface effect when H-COFs were formed into C-COFs under titanium acid. The structure characteristics, photoelectric performance, bandgap width and stability of C-COFs/TiO2 were confirmed through characterization analysis. C-COFs/TiO2 exhibit strong stability, conjugation effects, electron deficiency effects, and catalytic efficiency. Hydrogen production rate up to 5598 μmol g−1 h−1 by C-COFs/TiO2 as photocatalyst. C-COFs/TiO2 lead to 161 times improvement in photocatalytic activity for TiO2 and 3.6 times improvement in photocatalytic activity for H-COFs. The catalytic reaction mechanism was obtained by utilizing experimental data and DFT calculation. This synergistic integration of organic inorganic combined catalyst provides a foundational framework for advancing research into novel photocatalysts.

Catalytic mechanism study of ATP-citrate lyase during citryl-CoA synthesis process

ATP-citrate lyase (ACLY) is a critical metabolic enzyme and promising target for drug development. The structure determinations of ACLY have revealed its homotetramer states with various subunit symmetries, but catalytic mechanism of ACLY tetramer and the importance of subunit symmetry have not been clarified. Here, we constructed the free energy landscape of ACLY tetramer with arbitrary subunit symmetries and investigated energetic and conformational coupling of subunits during citryl-CoA synthesis process. The optimal conformational pathway indicates that ACLY tetramer encounters three critical conformational barriers and undergoes a loss of rigid-D2 symmetry to gain an energetic advantage. Energetic coupling of conformational changes and biochemical reactions suggests that these biological events are not independent but rather coupled with each other, showing a comparable energy barrier to the experimental data for the rate-limiting step. These findings could contribute to further research on catalytic mechanism, functional modulation, and inhibitor design of ACLY.