Catalytic Active Sites Research Articles

Engineering active sites in ternary CeO2-CuO-Mn3O4 heterointerface embedded in reduced graphene oxide for boosting water splitting activity

The rational design of highly efficient and stable bifunctional catalysts for overall water splitting is vitally important. In this study, to increase the active catalytic sites of CeO2 for electrochemical water splitting, a ternary CeO2-CuO-Mn3O4 heterostructure, synthesized by coprecipitation method, is loaded on reduced graphene oxide (rGO) nanosheets in different amounts to produce CeO2-CuO-Mn3O4@rGO nanocomposites. It is found that CeO2-CuO-Mn3O4@rGO nanocomposites show higher electrocatalytic activity than unsupported samples, and the best activity is observed when the wieght ratio of CeO2-CuO-Mn3O4 is three times that of rGO. The CeO2-CuO-Mn3O4@rGO(3:1) requires low overpotentials of 130 and 270 mV for hydrogen and oxygen evolution reactions (HER and OER) at a current density of 10 mA cm−2. Furthermore, this material demonstrates a large electrochemically active surface area, low charge transfer resistance, suitable kintics, and high long-term stability for both OER and HER. Additionally, when CeO2-CuO-Mn3O4@rGO(3:1) is used as self-supported electrodes for the overall water splitting reaction, a low cell voltage of 1.68 V is obtained. This superior performance is due to: (i) active multi-metal sites that produce strong synergistic effects; (ii) the high conductivity of rGO, which faciliate favorable electron transfer; and (iii) the homogenous anchoring of CeO2-CuO-Mn3O4 on rGO, which increases the number of active sites available on the catalyst surface.

Template-directed synthesis of Co, N-doped carbon spheres for efficient oxygen reduction reaction

An efficient template-directed strategy is proposed in this study to synthesize nitrogen-doped carbon spheres supported Co nanoparticles (Co@NCS), using polydopamine and ZnCo-based zeolite imidazole framework as the precursors. Benefiting from the integration of abundantly catalytic active sites, highly electronic conductivity, and hierarchically porous structure, the obtained Co@NCS displays impressive electrocayalytic performances. In an alkaline electrolyte, the Co@NCS catalyst delivers a half-wave potential of 0.84 V for oxygen reduction reaction (ORR) and an overpotential of 430 mV for oxygen evolution reaction (OER) at 10 mA cm−2, along with a superb durability and methanol tolerance. In addition, the zinc-air battery with Co@NCS as electrode catalyst affords a high specific capacity/power density as well as an intriguing long-cycle discharge–charge property, exhibiting a promising application prospect in the field of renewable resources.

Efficient tetracycline hydrochloride degradation via peroxymonosulfate activation by N doped coagulated sludge based biochar: Insights on the nonradical pathway.

Coagulation could effectively remove microplastics (MPs). However, MPs coagulated sludge was still a hazardous waste that is difficult to degrade. Nitrogen-doped carbon composite (N-PSMPC) was prepared by carbonizing MPs coagulated aluminum sludge (MP-CA) doped with cheap urea in this study. Compared with the carbon material (PSMPC) produced by direct carbonization of MP-CA, N-PSMPC had a higher degree of defects, which could provide more active sites for peroxymonosulfate (PMS) activation. And then, the N-PSMPC was applied to the degradation of tetracycline hydrochloride (TC). The results showed that the N-PSMPC/PMS system exhibited excellent TC degradation performance at the pH range of 3-9, and the coexistence of CO32- and HCO3- inhibited the TC degradation. Moreover, the graphite N, pyridine N and carbonyl group were identified as the primary catalytic active sites. Three TC degradation pathways were speculated based on the intermediates detected by liquid chromatography-mass spectrometry, and the degradation mechanism was dominated by the nonradical pathway. In addition, the analysis of TC and intermediates by toxicity assessment software showed that N-PSMPC/PMS system could mitigate the TC toxicity. This study will provide a novel approach for the resourceful utilization of MP-CA and provide technical support for the removal of MPs and TC in water.

DFT Study of the ORR Catalytic Activity of As-Doped and As-N Co-Doped Graphene Substrates.

This study employs first-principles methods to investigate the ORR catalytic activity of As-doped and AsN co-doped graphene. As atoms, as catalytic active sites, exhibit excellent catalytic activity. Due to the strong interaction between As and N, the stability of the As-N co-doped substrate is enhanced. In particular, As-N4 co-doped graphene not only demonstrates the best thermodynamic and kinetic stability, but also has an ORR overpotential of only 0.53 V. We also propose a method to predict the Gibbs free energy change of the system by calculating the adsorption energies of the adsorbates. This approach can streamline the process by eliminating the need to calculate the Gibbs free energy of the ORR system, making it highly advantageous for future studies on the ORR catalytic activity of multi-impurity co-doped graphene.

Elucidation of the biosynthetic pathways of timosaponins reveals the antifungal mechanisms in Anemarrhena asphodeloides.

Timosaponins, as steroidal saponins, are the primary active constituents and quality biomarkers in Anemarrhena asphodeloides Bunge. Despite their significance, the biosynthetic pathways of timosaponins have not been thoroughly investigated. This study aims to delineate the biosynthetic pathway of timosaponins in A. asphodeloides, elucidate the catalytic mechanisms of the key cycloartenol synthase (CAS), and investigate the antifungal properties of timosaponins. Genes were cloned from A. asphodeloides and heterologous expressed in yeast, tobacco or bacillus coli. Site-directed mutagenesis and molecular docking were used to elucidate the catalytic mechanism of CAS. Antifungal assays were conducted to evaluate the antifungal activities of timosaponins. In this study, we elucidated the biochemical functions of seven genes involved in timosaponins biosynthesis in A. asphodeloides. Among three candidate OSC genes, AaOSCR12 was identified as the gene encoding cycloartenol synthase, which is responsible for the skeleton cyclization in timosaponin biosynthesis. Six residues (257H, 369N, 448T, 507V, 558P, 616Y) were identified as the critical catalytic active sites of CAS (AaOSCR12). Sterol methyltransferase (AaSMT1) and sterol side-chain reductase (AaSSR2) were found to be the subsequent enzymes and the branching points leading to phytosterol and cholesterol biosynthesis, respectively. Two oxide reductase genes, AaCYP90B27 and AaCYP90B2, were responsible for post-modification of cholesterol, serving as a precursor of timosaponins. A key 26-O-β-glucosidase (AaF26G1) was identified as facilitating the conversion of furostanol-type timosaponins into spirostanol-type timosaponins. Antifungal assays revealed that spirostanol-type timosaponin AⅢ exhibits superior antifungal activity compared to furostanol-type timosaponin BⅡ, potentially linked to plant defense mechanisms involving AaF26G1. This study utilized a multi-chassis cross-identification strategy, revealing key enzymes in the timosaponin biosynthetic pathway and offering novel insights into plant defense mechanisms against microbial pathogens.

Light‐induced Enhancement of Energetic Charge Carrier Extraction and Modulation of Local Charge Density to Impact Selectivity in Plasmonic Nanometals

AbstractLocalized surface plasmon resonance (LSPR) metals exhibit remarkable light‐absorbing property and unique catalytic activity, attracting significant attention in photocatalysts recently. However, the practical application of plasmonic nanometal is hindered by challenge of energetic electrons extraction and low selectivity. The energetic carriers generated in nanometal under illumination have extremely short lifetimes, leading to rapid energy loss. In this work, silver nanometals modified with five distinct sulfhydryl ligands (re‐Ag‐S‐R) were synthesized via photoreduction of superlattice precursors. Modified surface efficiently extracts and preserves excited state electrons of plasmonic nanometals. By modulation the local charge density at catalytic active sites through substituents with varying electron‐donating and electron‐withdrawing properties, the selectivity of the photocatalytic carbon dioxide reduction reaction and hydrogen evolution reaction was influenced. The results demonstrated opposite selectivity between methoxy‐modified re‐Ag‐S‐OCH3 (CO selectivity of 96.73 %) and amino‐modified re‐Ag‐S‐NH2 (H2 selectivity of 96.66 %) despite their similar structures. The changes in excited states and surface contact potentials induced by LSPR were monitored using femtosecond transient absorption (fs‐TA) spectroscopy and Kelvin probe force microscopy (KPFM). Meanwhile, the detailed discussion of the LSPR mechanism in plasmonic nanometals will serve as valuable references and foundational elements for future research in this area.

Amine functionalized magnetic resorcinol formaldehyde as a green and reusable nanocatalyst for the Knoevenagel condensation

Herein, a novel amine-functionalized magnetic resorcinol-formaldehyde with a core-shell structure (Fe3O4@RF/Pr-NH2) is prepared through the chemical immobilization of (3-aminopropyl)trimethoxysilane over Fe3O4@RF composite. Characterization through FT-IR, EDX, PXRD, and TGA confirmed successful surface modification while preserving the crystalline structure of Fe3O4. The VSM analysis demonstrated excellent superparamagnetic properties, and SEM and TEM images revealed spherical particles for the designed nanocatalyst. The Fe3O4@RF/Pr-NH2 nanocomposite was employed as a robust nanocatalyst to promote the Knoevenagel condensation of benzaldehydes with ethyl cyanoacetate and malononitrile, resulting in the formation of substituted olefins. Various aromatic aldehydes were used as substrates in the presence of 0.01 g of Fe3O4@RF/Pr-NH2, achieving high to excellent yields (87–97%) within short reaction times (10–50 min) in EtOH at 60 °C. The high performance of Fe3O4@RF/Pr-NH2 is attributed to the hydrophobic nature of RF shell, which facilitates the accumulation of organic precursors around the catalytic active sites and enhances product yields. The designed magnetic catalyst could retain its high efficiency for at least ten runs. The metal-free, low-cost, and environmentally friendly attributes of the Fe3O4@RF/Pr-NH2 catalyst make it a promising alternative to traditional metal-based catalysts.

Surface Bi-vacancy and corona polarization engineered nanosheets with sonopiezocatalytic antibacterial activity for wound healing.

Piezocatalytic therapy is an emerging therapeutic strategy for eradicating drug-resistant bacteria, but suffers from insufficient piezoelectricity and catalytic active site availability. Herein, Bi-vacancies (BiV) and corona polarization were introduced to BiOBr nanosheets to create a BiOBr-BiVP nanoplatform for piezocatalytic antibacterial therapy. This meticulously tailored strategy strengthens the built-in electric field of nanosheets, enhancing piezoelectric potential and charge density and boosting charge separation and migration efficiency. Meanwhile, BiV adeptly adjust the band structure and increase reaction sites. Ultrasonication of nanosheets continuously enables the generation of reactive oxygen species (ROS) and CO, facilitating almost 100% broad-spectrum antibacterial efficacy. BiOBr-BiVP nanosheets demonstrate full bacterial eradication and accelerate wound healing through simultaneous regulation of inflammatory factors, facilitation of collagen deposition, and promotion of angiogenesis. Overall, this ultrasonic-triggered piezocatalytic nanoplatform combines BiV and the corona polarization strategy, providing a robust strategy for amplifying piezocatalytic mediated ROS/CO generation for drug-resistant bacterial eradication.

Multifunctional Nanozyme with Aptamer-Based Ratiometric Fluorescent and Colorimetric Dual Detection of Prostate-Specific Antigen.

The adsorption of DNA probes onto nanomaterials represents a promising bioassay technique, generally employing fluorescence or catalytic activity to generate signals. A significant challenge is maintaining the catalytic activity of chromogenic catalysts during detection while enhancing accuracy by overcoming the limitations of single-signal transmission. This article presents an innovative multimodal analysis approach that synergistically combines the oxidase-like activity of Fe-N-C nanozyme (Fe-NC) with red fluorescent carbon quantum dots (R-CQDs), further advancing the dual-mode analysis method utilizing R-CQDs@Fe-NC. In this system, R-CQDs integrate with Fe-NC to provide a steady reference red fluorescence signal, while Fe-NC serves as the catalytic active site. The adsorption of 6-carboxyfluorescein-labeled aptamers (FAM-apt) significantly enhanced the electron transfer capability of R-CQDs@Fe-NC, enhancing its catalytic performance and resulting in increased oxidation of 3,3',5,5'-tetramethylbenzidine (TMB). Concurrently, the green fluorescence of FAM-apt diminishes due to energy competition, photoinduced electron transfer, and the internal filtration effect by R-CQDs@Fe-NC, while the red fluorescence from R-CQDs@Fe-NC remains stable. Upon recognizing and binding to prostate-specific antigen (PSA), FAM-apt detaches from the surface of R-CQDs@Fe-NC. This leads to simultaneous variations in both the fluorescence signal of the system and the colorimetric signal of TMB. Based on these properties, a colorimetric/fluorescence dual-mode detection method for PSA was established, with detection limits of 0.054 and 0.16 ng/mL, respectively. Furthermore, a smartphone-based sensing device facilitated rapid and convenient detection. This study presents a multisignal output sensing strategy and a simple capillary sensing device, presenting a promising approach for PSA diagnostic analysis and the potential detection of other biomarkers.

Photothermal Catalysts, Light and Heat Management: From Materials Design to Performance Evaluation

AbstractPhotothermal catalysis, a frontier in heterogeneous catalysis, combines light‐driven and thermally enhanced chemical reactions to optimize energy use and reaction efficiencies at catalytic active sites. By leveraging photothermal conversion, this approach links renewable energy sources with industrial chemical processes, offering significant potential for sustainable applications. This review categorizes photothermal catalysis into three types: light‐driven thermocatalysis, thermally enhanced photocatalysis, and photo‐thermo coupling catalysis. Each category is analyzed, emphasizing mechanisms, performance factors, and the role of advanced materials such as plasmonic nanoparticles, semiconductors, and hybrid composites in enhancing light absorption, thermal distribution, and catalytic stability. Key challenges include achieving uniform thermal and photonic energy distributions within catalytic reactors and developing accurate performance evaluation metrics. Applications such as CO₂ reduction, ammonia synthesis, and plastic upcycling highlight the environmental and industrial relevance of this technology. The review identifies limitations and suggests innovations in materials design and energy‐storing mechanisms to enable continuous catalytic processes. Future directions emphasize photothermal catalysis's potential to transform sustainable energy systems and advance green chemical production. This synthesis aims to guide research and foster practical adoption of photothermal technologies at an industrial scale.

Establishment of Gas-Liquid-Solid Interface on Multilevel Porous Cu2O for Potential-Driven Selective CO2 Electroreduction toward C1 or C2 Products.

Copper-based catalysts demonstrate distinctive multicarbon product activity in the CO2 electroreduction reaction (CO2RR); however, their low selectivity presents significant challenges for practical applications. Herein, we have developed a multilevel porous spherical Cu2O structure, wherein the mesopores are enriched with catalytic active sites and effectively stabilize Cu+, while the macropores facilitate the formation of a "gas-liquid-solid" three-phase interface, thereby creating a microenvironment with an increasing water concentration gradient from the interior to the exterior. Potential-driven phase engineering and protonation synergistically optimize the reaction pathway, facilitating a switch between CO and C2H4. At a low current density of 100 mA cm-2, the faradaic efficiency (FE) for CO reaches an impressive 96.97%. When the current density increases to 1000 mA cm-2, FEC2H4 attains 53.05%. Experiments and theoretical calculations indicate that at lower potentials, the pure Cu2O phase diminishes the adsorption of *CO intermediates, while weak protonation inhibits hydrogen evolution reactions, thereby promoting CO production. Conversely, at more negative potentials, the Cu0/Cu+ interface and strong protonation generate locally elevated concentrations of *CO and *COOH intermediates, which enhance C-C coupling and deep hydrogenation, ultimately improving selectivity toward C2+ products. This study provides novel insights into the rational design of copper-based catalysts for customizable CO2 electroreduction products.

Tuning Dual Catalytic Active Sites of Pt Single Atoms Paired with High-Entropy Alloy Nanoparticles for Advanced Li-O2 Batteries.

To achieve a long cycle life and high-capacity performance for Li-O2 batteries, it is critical to rationally modulate the formation and decomposition pathway of the discharge product Li2O2. Herein, we designed a highly efficient catalyst containing dual catalytic active sites of Pt single atoms (PtSAs) paired with high-entropy alloy (HEA) nanoparticles for oxygen reduction reaction (ORR) in Li-O2 batteries. HEA is designed with a moderate d-band center to enhance the surface adsorbed LiO2 intermediate (LiO2(ads)), while PtSAs active sites exhibit weak adsorption energy and promote the soluble LiO2 pathway (LiO2(sol)). An optimal ratio between LiO2(ads) and LiO2(sol) pathway was realized to modulate PtSAs and HEA active sites via regulating the etching conditions in the dealloying synthesis process for obtaining high-performance Li-O2 batteries. The ORR kinetics are accelerated, and the parasitic reactions are restrained in the Li-O2 batteries. As a result, Li-O2 batteries based on the HEA@Pt-PtSAs catalyst demonstrate an ultralow overpotential (0.3 V) and ultralong cycling performance of 470 cycles at 1000 mA g-1. The insights into the synthetic strategies and the importance of balancing the ORR pathways will offer guidance for devising multisite synergistic catalysts to accelerate redox-reaction kinetics for Li-O2 batteries.

Determination of Site Occupancy in the M-Pd-Zn (M = Cu, Ag, and Au) γ-Brass Phase by CALculation of PHAse Diagrams Modeling and Rietveld Refinement.

The Pd-Zn γ-brass phase provides exciting opportunities for synthesizing site-isolated catalysts with precisely controlled Pd active site ensembles. Introducing a third metallic element into the γ-brass lattice further perturbs the catalytic active site ensembles. Here, we introduce coinage metallic elements M (M = Cu, Ag, and Au) into the Pd-Zn γ-brass phase and investigate the site occupation factors of each element in the γ-brass lattice. The CALculation of PHAse Diagrams (CALPHAD) modeling approach supported by energetics predicted by the density functional theory and X-ray and neutron diffraction with Rietveld refinement were used to identify the SOF on each Wyckoff site for various M amounts alloyed into the Pd-Zn γ-brass phase. The present analysis unveils the strong preference for Pd occupying the outer tetrahedral (OT) site in the γ-brass lattice, while the coinage metallic elements tend to substitute for Zn on the octahedral (OH) site. The determination of site occupancy in the bulk M-Pd-Zn γ-brass phase provides opportunities to investigate and tailor potential catalytically active site ensembles in the γ-brass phase materials.

Light-induced Enhancement of Energetic Charge Carrier Extraction and Modulation of Local Charge Density to Impact Selectivity in Plasmonic Nanometals.

Localized surface plasmon resonance (LSPR) metals exhibit remarkable light-absorbing property and unique catalytic activity, attracting significant attention in photocatalysts recently. However, the practical application of plasmonic nanometal is hindered by challenge of energetic electrons extraction and low selectivity. The energetic carriers generated in nanometal under illumination have extremely short lifetimes, leading to rapid energy loss. In this work, silver nanometals modified with five distinct sulfhydryl ligands (re-Ag-S-R) were synthesized via photoreduction of superlattice precursors. Modified surface efficiently extracts and preserves excited state electrons of plasmonic nanometals. By modulation the local charge density at catalytic active sites through substituents with varying electron-donating and electron-withdrawing properties, the selectivity of the photocatalytic carbon dioxide reduction reaction and hydrogen evolution reaction was influenced. The results demonstrated opposite selectivity between methoxy-modified re-Ag-S-OCH3 (CO selectivity of 96.73%) and amino-modified re-Ag-S-NH2 (H2 selectivity of 96.66%) despite their similar structures. The changes in excited states and surface contact potentials induced by LSPR were monitored using femtosecond transient absorption (fs-TA) spectroscopy and Kelvin probe force microscopy (KPFM). Meanwhile, the detailed discussion of the LSPR mechanism in plasmonic nanometals will serve as valuable references and foundational elements for future research in this area.

Site-Specific for CO2 Photoreduction with Single-Atom Ni on Strained TiO2-x Derived from Bimetallic Metal-Organic Frameworks.

The photocatalytic reduction of CO2 in water to produce fuels and chemicals is promising while challenging. However, many photocatalysts for accomplishing such challenging task usually suffer from unspecific catalytic active sites and the inefficient charge carrier's separation. Here, a site-specific single-atom Ni/TiO2-x catalyst is reported by in situ topological transformation of Ni-Ti-EG bimetallic metal-organic frameworks. The loading of nickel nanoparticles or individual atoms, which act as specific active sites, can be precisely regulated by chelating agents through the partial removal of nickel and adjacent oxygen atoms. Furthermore, the degree of lattice strain in Ni/TiO2-x catalysts, which improves the separation efficiency of charge carriers, can be modulated by fine-tuning the transformation process. By leveraging the anchored nickel atoms and the strained TiO2, the optimized NiSA0.27/TiO2-x shows a CO generation rate of 86.3 µmol g-1 h-1 (288 times higher than that of NiNPs/TiO2-x) and CO selectivity of up to 92.5% for CO2 reduction in a pure-water system. This work underscores the importance of tailoring lattice strain and creating specific single-atom active sites to facilitate the efficient and selective reduction of CO2.

Upconverter loaded MoS2 counter electrode for broadband dye-sensitized solar cell applications.

An interesting approach of including an upconverter in the MoS2 counter electrode can yield broadband light harvesting Pt-free DSSC assembly. Here different upconverter (UC) nanoparticles (Yb, Er incorporated NaYF4, YF3, CeO2 & Y2O3) were synthesized and loaded in MoS2 thin film by hydrothermal method. The inclusion of UCs in MoS2 films exposed without any secondary formation of upconverters and the uniform deposition of the films are confirmed through XRD and FESEM analysis respectively. The absorption spectrum (UV-Vis-NIR) confirms the increase in absorption intensity in visible and NIR regions due to the incorporation of UCs. Under 980nm excitation, the UCs-loaded MoS2 films show emission in blue (450-490nm), green (520-540nm) and red (600-700nm) regions due to the f-f inner transition occurring in the Er ions. The oxide and fluoride UCs-based DSSCs were fabricated with an FTO/TiO2/N719/Triiodide electrolyte/UC@MoS2/FTO assembly. Oxide UCs show greater electrocatalytic activity, which might be owed to the films exposed with more catalytic active sites favourable for ion transportation in the I-/I- 3 electrolyte. Among them, higher photoconversion efficiency (PCE) of 7.1% was witnessed for (Y2O3: Er, Yb) @MoS2 counter electrode-based DSSC which is due to the good conductivity (RS) of the film, the longer electron lifetime and photon harvesting enhancement by upconversion process. It is notably convinced that the UC-loaded MoS2 films can be used as an effective counter electrode for the possible realization of upconverter DSSC and used for broadband light absorption.

High-Resolution Mapping of Photocatalytic Activity by Diffusion-Based and Tunneling Modes of Photo-Scanning Electrochemical Microscopy.

Semiconductor nanomaterials and nanostructured interfaces have important technological applications, ranging from fuel production to electrosynthesis. Their photocatalytic activity is known to be highly heterogeneous, both in an ensemble of nanomaterials and within a single entity. Photoelectrochemical imaging techniques are potentially useful for high-resolution mapping of photo(electro)catalytic active sites; however, the nanoscale spatial resolution required for such experiments has not yet been attained. In this article, we report photoreactivity imaging of two-dimensional MoS2 photocatalysts by two modes of photoscanning electrochemical microscopy (photo-SECM): diffusion and tunneling-based modes. Diffusion-based (feedback mode) photo-SECM is used to map the electron transfer and hydrogen evolution rates on mixed-phase MoS2 nanosheets and MoS2 chemical vapor deposition (CVD)-grown triangles. An extremely high resolution of photoelectrochemical imaging (about 1-2 nm) by the tunneling mode of the photo-SECM is demonstrated.

Photo-Driven Ammonia Synthesis via a Proton-Mediated Photoelectrochemical Device.

N2 reduction reaction (NRR) by light is an energy-saving and sustainable ammonia (NH3) synthesis technology. However, it faces significant challenges, including high energy barriers of N2 activation and unclear catalytic active sites. Herein, we propose a strategy of photo-driven ammonia synthesis via a proton-mediated photoelectrochemical device. We used redox-catalysis covalent organic framework (COF), with a redox site (-C=O) for H+ reversible storage and a catalytic site (porphyrin Au) for NRR. In the proton-mediated photoelectrochemical device, the COF can successfully store e- and H+ generated by hydrogen oxidation reaction, forming COF-H. Then, these stored e- and H+ can be used for photo-driven NRR (108.97 umol g-1) under low proton concentration promoted by the H-bond network formed between -OH in COF-H and N2 on Au, which enabled N2 hydrogenation and NH3 production, establishing basis for advancing artificial photosynthesis and enhancing ammonia synthesis technology.

Triethylamine regulated MOFs-derived peroxidase-like nanozymes for colorimetric analysis of glyphosate with boosted catalytic activity

Developing accurate and rapid methods for analyzing organophosphorus pesticides is essential to ensure water quality and food safety due to their significant chemical and biological toxicity. This study presents a novel colorimetric sensor for glyphosate based on inhibiting Fe/ZnO nanozyme activity. By doping with iron and modulating the growth process of Fe/Zn MOFs precursors with triethylamine (TEA), Fe/ZnO nanozymes with substantial active surfaces and abundant Fe active sites were derived. The Fe/ZnO possessed excellent peroxidase-like activities, measuring 15.3 and 7.5 times higher than those of the materials synthesized without iron doping (ZnO) and the use of TEA (Fe/ZnO-w), respectively. Glyphosate inhibited the enzyme-like activity of Fe/ZnO by adsorbing on its surface through electrostatic interaction and occupying its catalytic active site. Based on this mechanism, a colorimetric sensing assay was created to directly and selectively detect glyphosate. The linear range for glyphosate detection was 0.02 to 10 mg L−1, with a detection limit (3σ) of 15.6 μg L−1. The proposed method has been successfully applied to the analysis of real samples. Metal oxides derived from well-designed MOFs provide a simple and effective strategy for creating high-performing pesticide detection platforms.

A review of metal catalysts for lithium-sulfur battery applications

When compared to ordinary lithium batteries now on the market, lithium-sulfur batteries stand out as the future research direction for energy storage systems owing to their higher volumetric energy density, theoretical specific energy, and gravimetric energy density. However, Li-S batteries’ drawbacks have significantly impeded their use and commercialization. A series of problems such as shuttle effects and volume expansion can remarkably reduce the service lifespan of Li-S batteries. By adding metal catalysts to the positive electrode of Li-S batteries, it is possible to improve the reaction kinetics of these batteries and efficiently address issues like the shuttle effect. During the paper, metal catalysts are separated into three groups based on the many ways they express themselves: metal single-atom catalysts, metal nanocatalysts, and metal compound catalysts. Metal single atom catalysts have catalytic active sites that are shaped like a single metal atom. Metal nanocatalysts are catalysts composed of metal particles with a size of 1-100 nm. Metal compound catalysts refer to catalysts composed of compounds formed by metals and other elements (such as oxygen, nitrogen, sulfur, etc.), including metal oxides, metal nitrides, metal sulfides, etc. It also lists and summarises the research progress of previous generations for the reference of related personnel.