Browse
Submit Data
Databases
API
Help

Dataset Information

16 Views

0 Connections

0 Citations

0 Reanalyses

0 Downloads

Omics score: 0

Revealing the Intrinsic Peroxidase-Like Catalytic Mechanism of Heterogeneous Single-Atom Co-MoS₂.

ABSTRACT: The single-atom nanozyme is a new concept and has tremendous prospects to become a next-generation nanozyme. However, few studies have been carried out to elucidate the intrinsic mechanisms for both the single atoms and the supports in single-atom nanozymes. Herein, the heterogeneous single-atom Co-MoS₂ (SA Co-MoS₂) is demonstrated to have excellent potential as a high-performance peroxidase mimic. Because of the well-defined structure of SA Co-MoS₂, its peroxidase-like mechanism is extensively interpreted through experimental and theoretical studies. Due to the different adsorption energies of substrates on different parts of SA Co-MoS₂ in the peroxidase-like reaction, SA Co favors electron transfer mechanisms, while MoS₂ relies on Fenton-like reactions. The different catalytic pathways provide an intrinsic understanding of the remarkable performance of SA Co-MoS₂. The present study not only develops a new kind of single-atom catalyst (SAC) as an elegant platform for understanding the enzyme-like activities of heterogeneous nanomaterials but also facilitates the novel application of SACs in biocatalysis.

SUBMITTER: Wang Y

PROVIDER: S-EPMC7770872 | biostudies-literature |

REPOSITORIES: biostudies-literature

ACCESS DATA

Json Xml

Similar Datasets

In situ synthesis of Co-doped MoS2 nanosheet for enhanced mimicking peroxidase activity.

Project description:To enhance the catalytic activity of two-dimensional layered materials as versatile materials, the modification of transition metal dichalcogenide nanosheets such as MoS2 by doping with heteroatoms has drawn great interests. However, few reports are available on the study of the enzyme-like activity of doped MoS2. In this study, a facile in situ hydrothermal method for the preparation of various ultrathin transition metals (Fe, Cu, Co, Mn, and Ni) doped MoS2 nanosheets has been reported. Through the density functional theory (DFT) and steady-state kinetic analysis, the Co-doped MoS2 nanosheets exhibited the highest peroxidase-like catalytic activity among them. Furthermore, a typical colorimetric assay for H2O2 was presented based on the catalytic oxidation of colorless 3,3',5,5'-tetramethylbenzidine (TMB) to a blue product (oxTMB) by Co-MoS2. The proposed colorimetric method showed excellent tolerance under extreme conditions and a broad linear range from 0.0005 to 25 mM for H2O2 determination. Concerning the practical application, in situ detection of H2O2 generated from SiHa cells was also fulfilled, fully confirming the great practicability of the proposed method in biosensing fields.Supplementary informationThe online version contains supplementary material available at 10.1007/s10853-022-07201-z.

| S-EPMC9036839 | biostudies-literature

Bismuth atom tailoring of indium oxide surface frustrated Lewis pairs boosts heterogeneous CO2 photocatalytic hydrogenation.

Project description:The surface frustrated Lewis pairs (SFLPs) on defect-laden metal oxides provide catalytic sites to activate H2 and CO2 molecules and enable efficient gas-phase CO2 photocatalysis. Lattice engineering of metal oxides provides a useful strategy to tailor the reactivity of SFLPs. Herein, a one-step solvothermal synthesis is developed that enables isomorphic replacement of Lewis acidic site In3+ ions in In2O3 by single-site Bi3+ ions, thereby enhancing the propensity to activate CO2 molecules. The so-formed BixIn2-xO3 materials prove to be three orders of magnitude more photoactive for the reverse water gas shift reaction than In2O3 itself, while also exhibiting notable photoactivity towards methanol production. The increased solar absorption efficiency and efficient charge-separation and transfer of BixIn2-xO3 also contribute to the improved photocatalytic performance. These traits exemplify the opportunities that exist for atom-scale engineering in heterogeneous CO2 photocatalysis, another step towards the vision of the solar CO2 refinery.

| S-EPMC7705729 | biostudies-literature

Catalytic mechanism of the glutathione peroxidase-type tryparedoxin peroxidase of Trypanosoma brucei.

Project description:Trypanosoma brucei, the causative agent of African sleeping sickness, encodes three nearly identical genes for cysteine-homologues of the selenocysteine-containing glutathione peroxidases. The enzymes, which are essential for the parasites, lack glutathione peroxidase activity but catalyse the trypanothione/Tpx (tryparedoxin)-dependent reduction of hydroperoxides. Cys47, Gln82 and Trp137 correspond to the selenocysteine, glutamine and tryptophan catalytic triad of the mammalian selenoenzymes. Site-directed mutagenesis revealed that Cys47 and Gln82 are essential. A glycine mutant of Trp137 had 13% of wild-type activity, which suggests that the aromatic residue may play a structural role but is not directly involved in catalysis. Cys95, which is conserved in related yeast and plant proteins but not in the mammalian selenoenzymes, proved to be essential as well. In contrast, replacement of the highly conserved Cys76 by a serine residue resulted in a fully active enzyme species and its role remains unknown. Thr50, proposed to stabilize the thiolate anion at Cys47, is also not essential for catalysis. Treatment of the C76S/C95S but not of the C47S/C76S double mutant with H2O2 induced formation of a sulfinic acid and covalent homodimers in accordance with Cys47 being the peroxidative active site thiol. In the wild-type peroxidase, these oxidations are prevented by formation of an intramolecular disulfide bridge between Cys47 and Cys95. As shown by MS, regeneration of the reduced enzyme by Tpx involves a transient mixed disulfide between Cys95 of the peroxidase and Cys40 of Tpx. The catalytic mechanism of the Tpx peroxidase resembles that of atypical 2-Cys-peroxiredoxins but is distinct from that of the selenoenzymes.

| S-EPMC2267296 | biostudies-literature

Electron tomography and fractal aspects of MoS2 and MoS2/Co spheres.

Project description:A study was made by a combination of 3D electron tomography reconstruction methods and N2 adsorption for determining the fractal dimension for nanometric MoS2 and MoS2/Co catalyst particles. DFT methods including Neimarke-Kiselev's method allowed to determine the particle porosity and fractal arrays at the atomic scale for the S-Mo-S(Co) 2D- layers that conform the spherically shaped catalyst particles. A structural and textural correlation was sought by further characterization performed by x-ray Rietveld refinement and Radial Distribution Function (RDF) methods, electron density maps, computational density functional theory methods and nitrogen adsorption methods altogether, for studying the structural and textural features of spherical MoS2 and MoS2/Co particles. Neimark-Kiselev's equations afforded the evaluation of a pore volume variation from 10 to 110?cm3/g by cobalt insertion in the MoS2 crystallographic lattice, which induces the formation of cavities and throats in between of less than 29?nm, with a curvature radius r k ?<?14.4?nm; typical large needle-like arrays having 20 2D layers units correspond to a model consisting of smooth surfaces within these cavities. Decreasing D P , D B , D I and D M values occur when Co atoms are present in the MoS2 laminates, which promote the formation of smoother edges and denser surfaces that have an influence on the catalytic properties of the S-Mo-S(Co) system.

| S-EPMC5615070 | biostudies-literature

In-situ spectroscopic probe of the intrinsic structure feature of single-atom center in electrochemical CO/CO2 reduction to methanol.

Project description:While exploring the process of CO/CO2 electroreduction (COxRR) is of great significance to achieve carbon recycling, deciphering reaction mechanisms so as to further design catalytic systems able to overcome sluggish kinetics remains challenging. In this work, a model single-Co-atom catalyst with well-defined coordination structure is developed and employed as a platform to unravel the underlying reaction mechanism of COxRR. The as-prepared single-Co-atom catalyst exhibits a maximum methanol Faradaic efficiency as high as 65% at 30 mA/cm2 in a membrane electrode assembly electrolyzer, while on the contrary, the reduction pathway of CO2 to methanol is strongly decreased in CO2RR. In-situ X-ray absorption and Fourier-transform infrared spectroscopies point to a different adsorption configuration of *CO intermediate in CORR as compared to that in CO2RR, with a weaker stretching vibration of the C-O bond in the former case. Theoretical calculations further evidence the low energy barrier for the formation of a H-CoPc-CO- species, which is a critical factor in promoting the electrochemical reduction of CO to methanol.

| S-EPMC10256813 | biostudies-literature

Tuning of structural and optical properties with enhanced catalytic activity in chemically synthesized Co-doped MoS2 nanosheets.

Project description:Molybdenum disulfide (MoS2) nanosheets, due to having a highly active nature, being low cost and having unique physical and chemical properties, have shown their efficacy in the catalytic reduction of nitroarenes. Doping of transition metal ions in molybdenum disulfide (MoS2) nanosheets is a well-known strategy to enhance their catalytic efficiency for the reduction of nitroarenes, however, finding the optimum dopant amount is still a subject of ongoing research. Herein, we have synthesized few-layered cobalt (Co) doped MoS2 nanosheets with different cobalt content (2%, 4%, 6% and 8%) through the solvothermal approach, taking sodium molybdate dihydrate (Na2MoO4·2H2O), thiourea (CH4N2S) and cobalt acetate tetrahydrate [Co(CH3COO)2·4H2O] as precursors and their catalytic performance has been affirmed by monitoring the reduction of p-nitrophenol by NaBH4 in real time using UV-visible absorption spectroscopy. The 6% Co doped MoS2 nanosheets have exhibited superior catalytic activity with a pseudo-first order rate constant of 3.03 × 10-3 s-1 attributed to the abundant defects in the active edge sites having a dominant metallic 1T phase with Co ion activated defective basal planes, sulphur (S) edges, synergistic structural and electronic modulation between MoS2 and Co ions and enhanced electron transfer assisted through redox cycling in the active sites. An attempt has also been made to study the manipulation of structural and optical properties with cobalt doping in MoS2 nanosheets to establish a correlation between the catalytic efficiency and dopant content. This study demonstrates that proper tuning of Co doping in MoS2 nanosheets paves the way in searching for a potential alternative of a noble metal catalyst for the catalytic reduction of nitroarenes.

| S-EPMC8693518 | biostudies-literature

Data on the catalytic mechanism of thiol peroxidase mimics.

Project description:We have recently reported SAR data describing the pharmacological activity of a series of phenyl alkyl selenides and tellurides which catalyse the oxidation of thiols by hydrogen peroxide (H2O2), "The design of redox active thiol peroxidase mimics: dihydrolipoic acid recognition correlates with cytotoxicity and prooxidant action" B. Zadehvakili, S.M. McNeill, J.P. Fawcett, G.I. Giles (2016) [1]. This thiol peroxidase (TPx) activity is potentially useful for a number of therapeutic applications, as it can alter the outcome of oxidative stress related pathologies and modify redox signalling. This article presents data describing the molecular changes that occur to a TPx mimic upon exposure to H2O2, and then the thiol mercaptoethanol, as characterised by UV-vis spectroscopy and HPLC retention time.

| S-EPMC4901149 | biostudies-literature

Catalytic Potential of Post-Transition Metal Doped Graphene-Based Single-Atom Catalysts for the CO2 Electroreduction Reaction.

Project description:Catalysts are required to ensure electrochemical reduction of CO2 to fuels proceeds at industrially acceptable rates and yields. As such, highly active and selective catalysts must be developed. Herein, a density functional theory study of p-block element and noble metal doped graphene-based single-atom catalysts in two defect sites for the electrochemical reduction of CO2 to CO and HCOOH is systematically undertaken. It is found that on all of the systems considered, the thermodynamic product is HCOOH. Pb/C3 , Pb/N4 and Sn/C3 are identified as having the lowest overpotential for HCOOH production while Al/C3 , Al/N4 , Au/C3 and Ga/C3 are identified as having the potential to form higher order products due to the strength of binding of adsorbed HCOOH.

| S-EPMC9315035 | biostudies-literature

Recoverable peroxidase-like Fe3O4@MoS2-Ag nanozyme with enhanced antibacterial ability.

Project description:Antibacterial agents with enzyme-like properties and bacteria-binding ability have provided an alternative method to efficiently disinfect drug-resistance microorganism. Herein, a Fe3O4@MoS2-Ag nanozyme with defect-rich rough surface was constructed by a simple hydrothermal method and in-situ photodeposition of Ag nanoparticles. The nanozyme exhibited good antibacterial performance against E. coli (~69.4%) by the generated ROS and released Ag+, while the nanozyme could further achieve an excellent synergistic disinfection (~100%) by combining with the near-infrared photothermal property of Fe3O4@MoS2-Ag. The antibacterial mechanism study showed that the antibacterial process was determined by the collaborative work of peroxidase-like activity, photothermal effect and leakage of Ag+. The defect-rich rough surface of MoS2 layers facilitated the capture of bacteria, which enhanced the accurate and rapid attack of •OH and Ag+ to the membrane of E. coli with the assistance of local hyperthermia. This method showed broad-spectrum antibacterial performance against Gram-negative bacteria, Gram-positive bacteria, drug-resistant bacteria and fungal bacteria. Meanwhile, the magnetism of Fe3O4 was used to recycle the nanozyme. This work showed great potential of engineered nanozymes for efficient disinfection treatment.

| S-EPMC7536174 | biostudies-literature

Visualizing hydrogen-induced reshaping and edge activation in MoS2 and Co-promoted MoS2 catalyst clusters.

Project description:Hydrodesulfurization catalysis ensures upgrading and purification of fossil fuels to comply with increasingly strict regulations on S emissions. The future shift toward more diverse and lower-quality crude oil supplies, high in S content, requires attention to improvements of the complex sulfided CoMo catalyst based on a fundamental understanding of its working principles. In this study, we use scanning tunneling microscopy to directly visualize and quantify how reducing conditions transforms both cluster shapes and edge terminations in MoS2 and promoted CoMoS-type hydrodesulfurization catalysts. The reduced catalyst clusters are shown to be terminated with a fractional coverage of sulfur, representative of the catalyst in its active state. By adsorption of a proton-accepting molecular marker, we can furthermore directly evidence the presence of catalytically relevant S-H groups on the Co-promoted edge. The experimentally observed cluster structure is predicted by theory to be identical to the structure present under catalytic working conditions.

| S-EPMC5992198 | biostudies-literature