Efficient Oxidation Research Articles

Engineering the Metal/Oxide Interfacial O‐Filling Effect to Tailor Oxygen Spillover for Efficient Acidic Water Oxidation

AbstractThe oxygen spillover on the metal/oxide electrocatalysts interface acts as an essential role in promoting the oxygen evolution reaction (OER) for proton exchange membrane water electrolyzers (PEMWEs). However, oxygen spillover mechanisms and corresponding regulatory strategies are still unclear for addressing slow OH‐migration kinetics. Herein, an interface is constructed between Iridium (Ir) and Niobium (Nb)‐doped Titanium oxide (TiO2) with abundant oxygen vacancies area by plasma processing, enabling oxygen spillover from the metal Ir to supports. The optimized Ir/Nb‐doped TiO2 with a significant OER activity (η = 253 mV) and durability in acids compared to commercial IrO2. In situ experiments combined with theoretical computations reveal the presence of interfacial oxygen vacancies not only regulates the Ir structure toward boosted activity but also constructs a directional spillover pathway from Ir to interfacial oxygen vacancies area and then TiO2 via the OH*‐filling route, which strikingly mitigates the OH* migration barriers. In addition, the optimized Ir/Nb‐doped TiO2 exhibits excellent performance (1.69 V/1.0 A cm−2@80 °C) and long‐term stability (≈500 h@1.0 A cm−2) with practical potential in PEMWEs. This work provides a unique insight into the role of oxygen spillover, paving the way for designing Ir‐based catalysts for PEMWEs.

Highly Efficient Removal of Organic Pollutants with HCO3−-Enhanced Ru(III)/NaClO Process

The design of efficient advanced oxidation processes (AOPs) in the presence of bicarbonate has long attracted considerable attention in the field of environmental catalysis. In this study, sodium bicarbonate (NaHCO3) as one of the most abundant substances in actual water, was introduced to a NaClO/Ru(III) system to enhance the removal of acid orange 7(AO7). NaHCO3 could significantly improve the removal efficiency of the Ru(III)/NaClO process in HCO3− at a pH range of 6.9–10.0. Ru(V)=O was identified as a dominant reactive species involved in the degradation of pollutants in the NaHCO3/NaClO/Ru(III) system. HCO3− interacts with Ru(III) to generate Ru(III)-HCO3−, which enhances the activation performance of Ru(III) under neutral or alkaline conditions. The removal of AO7 was significantly enhanced with increasing NaHCO3 concentration, and the rate constant increased more than 2-fold to 4-fold as NaHCO3 concentrations increased from 0 to 100 mM at pH 6.9 and 8.5. This study proposed a novel strategy to enhance the Ru(III)/NaClO process with environmentally friendly inorganic ligands and highlights its potential applications in the removal of pollutants.

Directed Evolution of Multicyclic Peptides Using Yeast Display for Sensitive and Selective Fluorescent Analysis of CD28 on the Cell Surface.

CD28 is a costimulatory receptor that provides the second signal necessary for T-cell activation and is associated with diseases, including rheumatoid arthritis, asthma, and cancer. Targeting CD28 is crucial for both functional bioanalysis and therapeutic development. Molecular probes, particularly fluorescent probes, can enhance our understanding of CD28's cellular roles. However, existing antibody-based probes face challenges such as high production costs, low stability, and large size, which limit their bioanalytical applications. Thus, there is a need for smaller, robust probes that enable the sensitive and selective targeting of CD28. Multicyclic peptides have emerged as promising candidates for novel therapeutics and molecular probes. Recently, we identified disulfide-directed multicyclic peptides (DDMPs) that bind CD28 with submicromolar affinity; however, their relatively low affinity limits further applications. In this study, we develop a DDMP evolving system based on yeast display and error-prone PCR to identify high-affinity peptide binders. We obtained DDMPs with a picomolar affinity for CD28, exceptional binding specificity, and remarkable oxidative folding efficiency. Furthermore, we developed fluorescent probes and labeling strategies for detecting and visualizing CD28 expression in human T cells. This advancement opens new avenues for studying T-cell dynamics and activation states, which are essential for understanding immune responses and developing targeted therapies. Our study not only produces potent CD28 binders and probes but also establishes a robust platform for optimizing other multicyclic peptide-based probes and therapeutics.

"Suspended" Single Rhenium Atoms on Nickel Oxide for Efficient Electrochemical Oxidation of Glucose.

Well-defined single-atom catalysts (SACs) serve as ideal model systems for directly comparing experimental results with theoretical calculations, offering profound insights into heterogeneous catalytic processes. However, precisely designing and controllably synthesizing SACs remain challenging due to the unpredictable structure evolution of active sites and generation of embedded active sites, which may bring about steric hindrance during chemical reactions. Herein, we present the precious nonpyrolysis synthesis of Re SACs with a well-defined phenanthroline coordination supported by NiO (Re1-phen/NiO). Multiple experimental characterizations together with theoretical calculations unravel the idea that the isolated Re atoms are suspended on the NiO surface, connected by phenanthroline ligands standing perpendicular to the surface. This unique structure provides the Re1-phen/NiO SAC with a strong capability to activate glucose molecules, enabling fully exposed Re=O double bonds in an open-ended reaction environment to simultaneously react with hydroxyl and aldehyde groups at both ends of the glucose molecule, rapidly forming glucaric acid.

Exploiting Lattice Carbon-Induced Modulation Effect in Nickel towards Efficient Alkaline Hydrogen Oxidation.

Doping with non-metallic heteroatom is an effective approach to tailor the electronic structure of Ni for enhancing its alkaline hydrogen oxidation reaction (HOR) catalytic performance. However, the modulation of HOR activity of Ni by lattice carbon (LC) atoms has rarely been reported, especially to reveal the rule between the doping effect and activity caused by the content of LC atoms. Here, hydrogen is proposed as a scavenger for LC atoms in the pyrolytic reduction process to finely control the content of LC atoms in Ni. With the removal of LC atoms in Ni lattice, the electronic structure changes from Ni3C-like electronic structure to quasi-Ni structure. Furthermore, a volcanic relationship between the LC content and HOR activity of Ni is established for the first time. The Cless-Ni (LC0.44-Ni) with optimized LC content shows the best activity owing to the weakened hydrogen binding energy (HBE) and optimal hydroxyl binding energy (OHBE). This work provides an inspiration for the design of high-performance catalysts by tailoring the electronic structure of the metal via LC atoms doping.

Exploiting Lattice Carbon‐Induced Modulation Effect in Nickel towards Efficient Alkaline Hydrogen Oxidation

Doping with non‐metallic heteroatom is an effective approach to tailor the electronic structure of Ni for enhancing its alkaline hydrogen oxidation reaction (HOR) catalytic performance. However, the modulation of HOR activity of Ni by lattice carbon (LC) atoms has rarely been reported, especially to reveal the rule between the doping effect and activity caused by the content of LC atoms. Here, hydrogen is proposed as a scavenger for LC atoms in the pyrolytic reduction process to finely control the content of LC atoms in Ni. With the removal of LC atoms in Ni lattice, the electronic structure changes from Ni3C‐like electronic structure to quasi‐Ni structure. Furthermore, a volcanic relationship between the LC content and HOR activity of Ni is established for the first time. The Cless‐Ni (LC0.44‐Ni) with optimized LC content shows the best activity owing to the weakened hydrogen binding energy (HBE) and optimal hydroxyl binding energy (OHBE). This work provides an inspiration for the design of high‐performance catalysts by tailoring the electronic structure of the metal via LC atoms doping.

Electro-Oxidation of Glycerol on Core–Shell M@Pt/C (M = Co, Ni, Sn) Catalysts in Alkaline Medium

This study explores the development of core–shell electrocatalysts for efficient glycerol oxidation in alkaline media. Carbon-supported M@Pt/C (M = Co, Ni, Sn) catalysts with a 1:1 atomic ratio of metal (M) to platinum (Pt) were synthesized using a facile sodium borohydride reduction method. The analysis confirmed the formation of the desired core–shell structure, with Pt dominating the surface as evidenced by energy-dispersive X-ray spectroscopy (EDS). X-ray diffraction (XRD) revealed the presence of a face-centered cubic (fcc) Pt structure for Co@Pt/C and Ni@Pt/C. Interestingly, Sn@Pt/C displayed a PtSn alloy formation indicated by shifted Pt peaks and the presence of minor Sn oxide peaks. Notably, no diffraction peaks were observed for the core metals, suggesting their amorphous nature. Electrocatalytic evaluation through cyclic voltammetry (CV) revealed superior glycerol oxidation activity for Co@Pt/C compared to all other catalysts. The maximum current density followed the order Co@Pt/C > Ni@Pt/C > Sn@Pt/C > Pt/C. This highlights the effectiveness of the core–shell design in enhancing activity. Furthermore, Sn@Pt/C displayed remarkable poisoning tolerance attributed to a combined effect: a bifunctional mechanism driven by Sn oxides and an electronic effect within the PtSn alloy. These findings demonstrate the significant potential of core–shell M@Pt/C structures for designing highly active and poisoning-resistant electrocatalysts for glycerol oxidation. The presented approach paves the way for further development of optimized catalysts with enhanced performance and stability aiming at future applications in direct glycerol fuel cells.

Introducing Sulfur in VNi-Layered Double Hydroxide Enables Efficient Electrocatalytic Oxidation of Benzylamine with High Current Densities.

The replacement of the thermodynamically unfavorable anodic oxygen evolution reaction (OER) with a more favorable organic oxidation reaction, such as the anodic oxidation of benzylamine, has garnered significant interest in hybrid water electrolyzer cells. This approach promises the production of value-added chemicals alongside hydrogen fuel generation, improving overall energy efficiency. However, achieving high current density for benzylamine oxidation without interference from OER remains a challenge, limiting the practical efficiency of the electrolyzer cell. In this study, we investigated a room temperature method for sulfur introduction in VNi-layered double hydroxide (LDH) catalyst and its application for electrocatalytic benzylamine oxidation. The S-introduction in VNi-LDH was found to modulate the electronic states of nickel and vanadium, increasing the number of active sites, electrochemical surface area, and charge transfer properties. The resulting S-VNi-LDH catalyst achieved a high current density of 400 mA cm-2 at only 1.39 V vs RHE potential for benzylamine oxidation, avoiding interference from oxygen evolution. The catalyst demonstrated 100% selectivity (Faradaic Efficiency = 98.6%) for the conversion of benzylamine into benzonitrile within 2.5 h of the reaction. In a two-electrode electrolysis system, S-VNi-LDH achieved a current density of 400 mA cm-2 at a cell voltage of 1.50 V when OER was substituted with benzylamine oxidation. The S-VNi-LDH showed energy consumption of 4.67 kWh/m3 H2 for OER and 1.31 kWh/m3 H2 during benzylamine oxidation, indicating a high energy efficiency with exceptional stability over five cycles, maintaining 98.6 ± 0.4% FE and consistent voltage. The S-VNi-LDH also oxidized various amines, including substituted benzylamines and secondary amines, achieving high conversion (95-97%) and faradaic efficiency (85.8-98%). This study presents an eco-friendly, room-temperature method for S-doping in VNi-LDH, which out performed the reported catalysts in the literature.

Enhanced Cooperative Generalized Compressive Strain and Electronic Structure Engineering in W-Ni3N for Efficient Hydrazine Oxidation Facilitating H2 Production.

As promising bifunctional electrocatalysts, transition metal nitrides are expected to achieve an efficient hydrazine oxidation reaction (HzOR) by fine-tuning electronic structure via strain engineering, thereby facilitating hydrogen production. However, understanding the correlation between strain-induced atomic microenvironments and reactivity remains challenging. Herein, a generalized compressive strained W-Ni3N catalyst is developed to create a surface with enriched electronic states that optimize intermediate binding and activate both water and N2H4. Multi-dimensional characterizations reveal a nearly linear correlation between the hydrogen evolution reaction (HER) activity and the d-band center of W-Ni3N under strain state. Theoretically, compressive strain enhances the electron transfer capability at the surface, increasing donation into antibonding orbitals of adsorbed species, which accelerates the HER and HzOR. Leveraging both compressive strain and the modified electronic structure from W incorporation, the W-Ni3N catalysts demonstrate outstanding bifunctional performance, achieving overpotentials of 46mV for HER at 10mA cm-2 and 81mV for HzOR at 100mA cm-2. Furthermore, W-Ni3N catalyst achieves efficient overall hydrazine splitting at a low cell voltage of 0.185V for 50mA cm-2, maintaining stability for ≈450 h. This work provides new insights into the dual engineering of strain and electronic structure in the design of advanced catalysts.

Identifying Upper d-Band Edge as Activity Descriptor for Ammonia Oxidation on PtCo Alloys in Low-Temperature Direct Ammonia Fuel Cells.

Low-temperature direct ammonia fuel cell (DAFC) stands out as a more secure technology than the hydrogen fuel cell system, while there is still a lack of elegant bottom-up synthesis procedures for efficient ammonia oxidation reaction (AOR) electrocatalysts. The widely accepted d-band center, even with consideration of the d-band width, usually fails to describe variations in AOR reactivity in many practical conditions, and a more accurate activity descriptor is necessary for a less empirical synthesis path. Herein, the upper d-band edge, εu, derived from the d-band model, is identified as an effective descriptor for accurately establishing the descriptor-activity relationship. Using the PtCo alloy with varying atomic composition as an example, the εu value succeeds in reflecting the corresponding trends of AOR activity, showing striking linear correlation with a coefficient of determination (R2) as high as 0.90. The effectiveness of the established descriptor-activity relationship is verified experimentally. The optimum electrocatalyst delivers an excellent peak current density of 74.04 A g-1 at 5 mV s-1, and the assembled DAFC generates a high power density, outperforming the majority of the extensively reported systems. This work brings fundamental insights into the relationship between chemical reactivity and electronic structure and benefits rational optimization of AOR electrocatalyst for next-generation low-temperature DAFC.

Potential Air Quality Side-Effects of Emitting H2O2 to Enhance Methane Oxidation as a Climate Solution.

Methane (CH4) is a greenhouse gas with a global warming potential 81.2 times higher than carbon dioxide (CO2). The intentional emission of oxidants into the atmosphere has been proposed as a geoengineering solution to accelerate the oxidation of CH4 to CO2, thereby reducing surface warming. However, there has been little consideration for competing atmospheric oxidation pathways that will reduce CH4 oxidation efficiencies and result in the formation of secondary pollutants such as ozone and particulate matter. Using a global chemical-transport model, we simulate a proposed technology to intentionally emit H2O2 into the atmosphere to elevate OH concentrations and enhance CH4 oxidation. We find that proposed emission rates of oxidants have minimal impacts on monthly average tropospheric ozone and particulate matter concentrations. However, competition for the oxidation of CH4 would necessitate widespread adoption of such technology to remove substantial concentrations of atmospheric CH4, which would in-turn cause considerable increases in regional winter-time particulate matter. Our work underscores the need to consider competing chemistry in evaluating the efficacy and side effects of proposals to enhance the atmospheric oxidation of CH4 as a climate solution.

Efficient Alkaline-Free Electrooxidation of 5-Hydroxymethylfurfural to 2,5-Furandicarboxylic Acid using Electrochemically-Charged NixCo1-x(OH)2 as a Redox Mediator.

Converting biomass-derived molecules like 5-hydroxymethylfurfural (HMF) into value-added products alongside hydrogen production using renewable energy offers significant opportunities for sustainable chemical and energy production. Yet, HMF electrooxidation requires strong alkaline conditions and membranes for efficient conversion. These harsh conditions destabilize HMF, leading to humin formation and reduced product purity, meanwhile membranes increase costs. Addressing these challenges, we introduce a two-step, decoupling system that operates without strong alkaline conditions and eliminates the need of membranes. In this system, nickel-cobalt hydroxides serve as effective redox mediators, driving HMF oxidation in pure water. The experimental results showed that Ni0.85Co0.15OOH effectively promotes the dehydrogenation of substrate and achieves a highly efficient oxidation of HMF in pure water, with the selectivity of product 2,5-furandicarboxylic acid (FDCA) approaching 100 %. This system has been expanded to oxidize various substrates, achieving yields exceeding 92 % for the corresponding acids of functionalized compounds such as furfuryl alcohol, furfural, benzyl alcohol, and benzaldehyde. By replacing fixed electrodes with flow electrodes, the scalability of decoupling strategy was evaluated for the harvesting of pure solid FDCA, highlighting the broad prospects in practical applications.

Efficient electrocatalytic glucose oxidation coupled water electrolysis driven by Ni-foam supported Ni–P nanowire arrays

Highly efficient electrocatalytic glucose oxidation reaction (GOR) using Ni–P@NF is realized and the mechanism is in situ explored. This catalyst also achieved superb hydrogen evolution and formic acid generation via GOR-assisted water electrolysis.

Boosting energy efficiency and selectivity of glucose oxidation toward glucuronic acid in high-frequency ultrasound using multicavity CuO catalytic cavitation agents

Reactive oxygen species generated from the inertial collapse of a gas bubble trapped on the surface of an MC-CuO cavity selectively oxidize glucose into glucuronic acid.

Unlocking the potential of simultaneous organics oxidation and nitrate reduction over an S-scheme magnetic CoFe2O4@g-C3N4 heterojunction under visible light irradiation: Performance and mechanism

In this study, a novel S-scheme CoFe2O4@g-C3N4 (CF@GCN) heterojunction was prepared via a simple hydrothermal method and its visible-light-driven catalytic potential was evaluated in terms of tetracycline (TC) oxidation and nitrate reduction simultaneously. A series of characterizations validated the effective fabrication of CF@GCN, exhibiting remarkable photocatalytic potentials. In the separated system of TC and nitrate, a nearly 100% removal of TC was observed in 60 min under the optimal conditions (pH = 5.0, Catalyst dosage = 0.4 g/L, TC concentration = 5.0 mg/L). The quenching experiments emphasized the concurrent participation of both non-radical species (h+) and radical species (O2•− and HO•) in TC degradation. Meanwhile, more than 96% of nitrate removal was observed in 90 min under the optimal conditions (pH = 3.0, Catalyst dosage = 0.4 g/L, nitrate concentration = 100 mg/L, in the presence of formic acid). In the combined system, both TC oxidation and nitrate reduction occurred simultaneously and the efficiency of TC oxidation was lower compared to the individual system. The novel S-scheme composite has demonstrated exceptional potential in enhancing the reusability and stability of the catalyst, even after five cycles of trials. A detailed mechanistic pathway for TC oxidation and nitrate reduction was proposed, relying on the identification of reactive species and intermediates. In general, our findings propose a promising method with synergistic properties for the simultaneous oxidation of organics and reduction of nitrate in wastewater over an S-scheme heterojunction.

Mitochondrial chaperonin DNAJC15 promotes vulnerability to ferroptosis of chemoresistant ovarian cancer cells.

DNAJC15 is a mitochondrial TIMM23-related co-chaperonin known for its role in regulating oxidative phosphorylation efficiency, oxidative stress response and lipid metabolism. Recently, it has been proposed that the loss of DNAJC15 correlates with cisplatin (CDDP)-resistance onset in ovarian cancer (OC), suggesting this protein as a potential prognostic factor during OC progression. However, the molecular mechanisms through which DNAJC15 contributes to CDDP response remains poorly investigated. Here, we show that high levels of DNAJC15 are associated with accumulation of lipid droplets, decreased tumorigenic features and increased sensitivity to CDDP in OC cells. When overexpressed, DNAJC15 induced a phenotype displaying increased lipid peroxidation and subsequent ferroptosis induction. To prove a role for DNAJC15-induced ferroptosis in promoting sensitivity to CDDP, we reduced lipid peroxidation upon Ferrostatin 1 treatment, which decreased cells' vulnerability to ferroptosis ultimately recovering their CDDP-resistant phenotype. In conclusion, our study uncovers the role of DNAJC15 in modulating ferroptosis activation and in the onset of CDDP resistance in OC cells.

Phosphorus dopants triggered enhanced bulk polarization and new active sites in hexagonal ZnIn2S4 toward efficient photocatalytic selective oxidation of benzyl alcohol coupled with H2 evolution

Phosphorus dopants triggered enhanced bulk polarization and new active sites in hexagonal ZnIn2S4 toward efficient photocatalytic selective oxidation of benzyl alcohol coupled with H2 evolution

One-step fabrication of free-standing copper/nickel composites for efficient electrocatalytic ammonia oxidation by bimetallic synergistic effect

One-step fabrication of free-standing copper/nickel composites for efficient electrocatalytic ammonia oxidation by bimetallic synergistic effect

Uv-light induced γ-MnO2 nanostructures with rich oxygen vacancies for efficient low-temperature catalytic oxidation of carbon monoxide

Uv-light induced γ-MnO2 nanostructures with rich oxygen vacancies for efficient low-temperature catalytic oxidation of carbon monoxide

Highly Efficient and Selectivity Controllable Aerobic Oxidation of Ethyl Lactate to Ethyl Pyruvate over VxOy/NC Catalyst

Developing effective catalysts for the selective oxidative dehydrogenation of ethyl lactate (EL) to value-added ethyl pyruvate (EP) is of great significance in biomass utilization. Herein, a series of VxOy/NC_P (P...