Prediction of perovskite oxygen vacancies for oxygen electrocatalysis at different temperatures.

Efficient catalysts are imperative to accelerate the slow oxygen reaction kinetics for the development of emerging electrochemical energy systems ranging from room-temperature alkaline water electrolysis to high-temperature ceramic fuel cells. In this work, we reveal the role of cationic inductive interactions in predetermining the oxygen vacancy concentrations of 235 cobalt-based and 200 iron-based perovskite catalysts at different temperatures, and this trend can be well predicted from machine learning techniques based on the cationic lattice environment, requiring no heavy computational and experimental inputs. Our results further show that the catalytic activity of the perovskites is strongly correlated with their oxygen vacancy concentration and operating temperatures.

Multivalence-State Tungsten Species Facilitated Iridium Loading for Robust Acidic Water Oxidation.

The development of the proton exchange membrane water electrolyzer (PEMWE) is still limited by the prohibitive cost and scarcity of iridium (Ir)-based oxygen evolution reaction (OER) catalyst. This work presents a novel catalyst synthesized by precursor-atomization and rapid joule-heating method, successfully doping iridium atoms into polyvalent tungsten blends (W, W, W) based on titanium substrate. The vacancy engineering of unsaturated tungsten oxide (W, W) reconstructs the electronic structure of the catalyst surface, which resulting in the low-valence state iridium species, avoiding excessive oxidation of iridium and accelerating the catalytic kinetics.

High-Valence-Manganese Driven Strong Anchoring of Iridium Species for Robust Acidic Water Oxidation.

Designing an efficient and durable electrocatalyst for the sluggish anodic oxygen evolution reaction (OER) has been the primary goal of using proton exchange membrane electrolyzer owing to the highly acidic and oxidative environment at the anode. In this work, it is reported that high-valence manganese drives the strong anchoring of the Ir species on the manganese dioxide (MnO ) matrix via the formation of an Mn-O-Ir coordination structure through a hydrothermal-redox reaction. The iridium (Ir)-atom-array array is firmly anchored on the Mn-O-Ir coordination structure, endowing the catalyst with excellent OER activity and stability in an acidic environment.

Anchoring Ni/NiO heterojunction on freestanding carbon nanofibers for efficient electrochemical water oxidation.

Rational design of low-cost and efficient electrocatalyst for the anodic oxygen evolution reaction (OER) to replace noble-metal-based catalysts is greatly desired for the large-scale application of water electrocatalysis. And compared with the conventional powdery catalysts, the freestanding electrode architecture is more attractive owing to the enhanced kinetics and stability. In this work, we report an electrospinning-carbonization-post oxidation strategy to develop the freestanding N-doped carbon nanofibers anchored with Ni/NiO nanoparticles (denoted as Ni/NiO-NCNFs) as efficient OER electrocatalyst.

Multiscale Engineering of Nonprecious Metal Electrocatalyst for Realizing Ultrastable Seawater Splitting in Weakly Alkaline Solution.

Seawater electrolysis is an attractive technique for mass production of high-purity hydrogen considering the abundance of seawater. Nevertheless, due to the complexity of seawater environment, efficient anode catalyst, that should be, cost effective, highly active for oxygen evolution reaction (OER) but negligible for Cl /ClO formation, and robust toward chlorine corrosion, is urgently demanded for large-scale application. Although catalysis typically appears at surface, while the bulk properties and morphology structure also have a significant impact on the performance, thus requiring a systematic optimization.

Defective Fe Metal-Organic Frameworks Enhance Metabolic Profiling for High-Accuracy Diagnosis of Human Cancers.

Cancers heavily threaten human life; therefore, a high-accuracy diagnosis is vital to protect human beings from the suffering of cancers. While biopsies and imaging methods are widely used as current technologies for cancer diagnosis, a new detection platform by metabolic analysis is expected due to the significant advantages of fast, simple, and cost-effectiveness with high body tolerance. However, the signal of molecule biomarkers is too weak to acquire high-accuracy diagnosis.

Single Carbon Vacancy Traps Atomic Platinum for Hydrogen Evolution Catalysis.

The coordinated configuration of atomic platinum (Pt) has always been identified as an active site with high intrinsic activity for hydrogen evolution reaction (HER). Herein, we purposely synthesize single vacancies in a carbon matrix (defective graphene) that can trap atomic Pt to form the Pt-C configuration, which gives exceptionally high reactivity for HER in both acidic and alkaline solutions. The intrinsic activity of Pt-C site is valued with a turnover frequency (TOF) of 26.

Mechanochemically Synthesised Flexible Electrodes Based on Bimetallic Metal-Organic Framework Glasses for the Oxygen Evolution Reaction.

The melting behaviour of metal-organic frameworks (MOFs) has aroused significant research interest in the areas of materials science, condensed matter physics and chemical engineering. This work first introduces a novel method to fabricate a bimetallic MOF glass, through melt-quenching of the cobalt-based zeolitic imidazolate framework (ZIF) [ZIF-62(Co)] with an adsorbed ferric coordination complex. The high-temperature chemically reactive ZIF-62(Co) liquid facilitates the formation of coordinative bonds between Fe and imidazolate ligands, incorporating Fe nodes into the framework after quenching.

Cobalt Electrochemical Recovery from Lithium Cobalt Oxides in Deep Eutectic Choline Chloride+Urea Solvents.

Electrochemical recovery of the cobalt in deep eutectic solvent shows its promise in recycling and recovery of valuable elements from the spent lithium-ion battery due to its high selectivity and minimal environmental impacts. This work unveiled the roles of the substrates, applied potentials, and operating temperatures on the performance of cobalt electrochemical recovery in a deep eutectic choline chloride+urea solvent. The solvent contains cobalt and lithium ions extracted from lithium cobalt oxides - 3an essential lithium-ion battery cathode material.

Porous Structure Engineering of Iridium Oxide Nanoclusters on Atomic Scale for Efficient pH-Universal Overall Water Splitting.

Water electrolysis, which is a promising high-purity H production method, lacks pH-universality; moreover, highly efficient electrocatalysts that accelerate the sluggish anodic oxygen evolution reaction (OER) are scarce. Geometric structure engineering and electronic structure modulation can be efficiently used to improve catalyst activity. Herein, a facile Ar plasma treatment method to fabricate a composite of uniformly dispersed iridium-copper oxide nanoclusters supported on defective graphene (DG) to form IrCuO @DG, is described.

Defect engineering and characterization of active sites for efficient electrocatalysis.

Electrocatalysis plays a decisive role in various energy-related applications. Engineering the active sites of electrocatalysts is an important aspect to promote their catalytic performance. In particular, defect engineering provides a feasible and efficient approach to improve the intrinsic activities and increase the number of active sites in electrocatalysts.

Gradient-Concentration Design of Stable Core-Shell Nanostructure for Acidic Oxygen Reduction Electrocatalysis.

Manipulating the surface structure of electrocatalysts at the atomic level is of primary importance to simultaneously achieve the activity and stability dual-criteria in oxygen reduction reaction (ORR) for proton exchange membrane fuel cells. Here, a durable acidic ORR electrocatalyst with the "defective-armored" structure of Pt shell and Pt-Ni core nanoparticle decorated on graphene (Pt-Ni@Pt /G) using a facile and controllable galvanic replacement reaction to generate gradient distribution of Pt-Ni composition from surface to interior, followed by a partial dealloying approach, leaching the minor nickel atoms on the surface to generate defective Pt skeleton shell, is reported. The Pt-Ni@Pt /G catalyst shows impressive performance for ORR in acidic (0.

Multiple Vacancies on (111) Facets of Single-Crystal NiFe O Spinel Boost Electrocatalytic Oxygen Evolution Reaction.

Oxygen evolution reaction (OER) as the rate-determining reaction of water splitting has been attracting enormous attention. At present, only some noble-metal oxide materials (IrO and RuO ) have been reported as efficient OER electrocatalysts for OER. However, the high cost and scarcity of these noble-metal oxide materials greatly hamper their large-scale practical application.

Sulfur-Modified Oxygen Vacancies in Iron-Cobalt Oxide Nanosheets: Enabling Extremely High Activity of the Oxygen Evolution Reaction to Achieve the Industrial Water Splitting Benchmark.

The oxygen vacancies of defective iron-cobalt oxide (FeCoO -Vo) nanosheets are modified by the homogeneously distributed sulfur (S) atoms. S atoms can not only effectively stabilize oxygen vacancies (Vo), but also form the Co-S coordination with Co active site in the Vo, which can modulate the electronic structure of the active site, enabling FeCoO -Vo-S to exhibit much superior OER activity. FeCoO -Vo-S exhibits a mass activity of 2440.

Understanding the Activity of Co-N C in Atomic Metal Catalysts for Oxygen Reduction Catalysis.

Atomic metal catalysis (AMC) provides an effective way to enhance activity for the oxygen reduction reaction (ORR). Cobalt anchored on nitrogen-doped carbon materials have been extensively reported. The carbon-hosted Co-N structure was widely considered as the active site; however, it is very rare to investigate the activity of Co partially coordinated with N, for example, Co-N C .

Fine-Tuning the Coordinatively Unsaturated Metal Sites of Metal-Organic Frameworks by Plasma Engraving for Enhanced Electrocatalytic Activity.

Metal-organic frameworks (MOFs) have recently emerged as promising electrocatalysts because of their atomically dispersed metal sites and porous structures. The active sites of MOF catalysts largely exist as coordinatively unsaturated metal sites (CUMSs). In this study, facile microwave-induced plasma engraving is applied to fine-tune the CUMSs of cobalt-based MOF (Co-MOF-74) without destroying its phase integrity by controlling the plasma-engraving species, intensity, and duration.

A Surfactant-Free and Scalable General Strategy for Synthesizing Ultrathin Two-Dimensional Metal-Organic Framework Nanosheets for the Oxygen Evolution Reaction.

Metal-organic framework (MOFs) two-dimensional (2D) nanosheets have many coordinatively unsaturated metal sites that act as active centres for catalysis. To date, limited numbers of 2D MOFs nanosheets can be obtained through top-down or bottom-up synthesis strategies. Herein, we report a 2D oxide sacrifice approach (2dOSA) to facilely synthesize ultrathin MOF-74 and BTC MOF nanosheets with a flexible combination of metal sites, which cannot be obtained through the delamination of their bulk counterparts (top-down) or the conventional solvothermal method (bottom-up).

Strontium-doped lanthanum iron nickelate oxide as highly efficient electrocatalysts for oxygen evolution reaction.

Pursuing efficient and low-cost catalysts for the sluggish oxygen evolution reaction (OER) is imperative for the large-scale deployment of promising electrochemical technologies such as water splitting and CO electrochemical reduction. The earth-abundant perovskite catalysts based on LaNiO show promise in OER catalysis because of their relatively low cost and their optimal electronic structure but suffer from low electrode-area normalized activity. In this work, we partially substituted La with Sr and Ni with Fe to enable a remarkably high OER activity with an ultra-low overpotential of 374 ± 3 mV vs RHE at a current density of 10 mA cm normalized by electrode geometric area.

Charge Polarization from Atomic Metals on Adjacent Graphitic Layers for Enhancing the Hydrogen Evolution Reaction.

Atomic metal species-based catalysts (AMCs) show remarkable possibilities in various catalytic reactions. The coordination configuration of the metal atoms has been widely recognized as the determining factor to the electronic structure and the catalytic activity. However, the synergistic effect between the adjacent layers of the multilayered AMCs is always neglected.

Defect-Induced Pt-Co-Se Coordinated Sites with Highly Asymmetrical Electronic Distribution for Boosting Oxygen-Involving Electrocatalysis.

Rational design and synthesis of hetero-coordinated moieties at the atomic scale can significantly raise the performance of the catalyst and obtain mechanistic insight into the oxygen-involving electrocatalysis. Here, a facile plasma-photochemical strategy is applied to construct atomically coordinated Pt-Co-Se moieties in defective CoSe (CoSe ) through filling the plasma-created Se vacancies in CoSe with single Pt atomic species (CoSe -Pt) under ultraviolet irradiation. The filling of single Pt can remarkably enhance the oxygen evolution reaction (OER) activity of CoSe .

Plasma-Triggered Synergy of Exfoliation, Phase Transformation, and Surface Engineering in Cobalt Diselenide for Enhanced Water Oxidation.

Various strategies, such as increasing active site numbers and structural and surface engineering, have been used to improve the oxygen evolution reaction (OER) performance of transition-metal dichalcogenides. However, it is challenging to combine these strategies in one system to realize the full catalytic potential. Now, an Ar/O plasma method is used to simultaneously induce exfoliation, surface reorganization (formation of an oxidative layer with rich oxygen vacancies), and phase transformation (cubic-to-orthorhombic) on CoSe to generate an exceptionally outstanding OER electrocatalysts.

Grafting Cobalt Diselenide on Defective Graphene for Enhanced Oxygen Evolution Reaction.

Cobalt diselenide (CoSe) has been demonstrated to be an efficient and economic electrocatalyst for oxygen evolution reaction (OER) both experimentally and theoretically. However, the catalytic performance of up-to-now reported CoSe-based OER catalysts is still far below commercial expectation. Herein, we report a hybrid catalyst consisting of CoSe nanosheets grafted on defective graphene (DG).

Coordination of Atomic Co-Pt Coupling Species at Carbon Defects as Active Sites for Oxygen Reduction Reaction.

Platinum (Pt) is the state-of-the-art catalyst for oxygen reduction reaction (ORR), but its high cost and scarcity limit its large-scale use. However, if the usage of Pt reduces to a sufficiently low level, this critical barrier may be overcome. Atomically dispersed metal catalysts with high activity and high atom efficiency have the possibility to achieve this goal.

Preparation and Properties of A Hyperbranch-Structured Polyamine adsorbent for Carbon Dioxide Capture.

A fibrous adsorbent with amino-terminated hyperbranch structure (PP-AM-HBP-NH) was prepared by grafting hyperbranched polyamine (HBP-NH) onto the acrylamide-modified polypropylene (PP) fibers. The grafting of AM on PP fibers provided the active sites for introducing HBP-NH onto the PP fibers. This kind of "grafting to" procedure to synthesize hyperbranch-structured fiber could overcome the disadvantages of stepwise growth procedure, avoiding the complicated synthesis process and the requirement of strict experimental conditions.

Ultrathin Iron-Cobalt Oxide Nanosheets with Abundant Oxygen Vacancies for the Oxygen Evolution Reaction.

Electrochemical water splitting is a promising method for storing light/electrical energy in the form of H fuel; however, it is limited by the sluggish anodic oxygen evolution reaction (OER). To improve the accessibility of H production, it is necessary to develop an efficient OER catalyst with large surface area, abundant active sites, and good stability, through a low-cost fabrication route. Herein, a facile solution reduction method using NaBH as a reductant is developed to prepare iron-cobalt oxide nanosheets (Fe Co -ONSs) with a large specific surface area (up to 261.