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 261.1 m g ), ultrathin thickness (1.2 nm), and, importantly, abundant oxygen vacancies. The mass activity of Fe Co -ONS measured at an overpotential of 350 mV reaches up to 54.9 A g , while its Tafel slope is 36.8 mV dec ; both of which are superior to those of commercial RuO , crystalline Fe Co -ONP, and most reported OER catalysts. The excellent OER catalytic activity of Fe Co -ONS can be attributed to its specific structure, e.g., ultrathin nanosheets that could facilitate mass diffusion/transport of OH ions and provide more active sites for OER catalysis, and oxygen vacancies that could improve electronic conductivity and facilitate adsorption of H O onto nearby Co sites.

The development of oxygen evolution reaction (OER) electrocatalysts remains a major challenge that requires significant advances in both mechanistic understanding and material design. Recent studies show that oxygen from the perovskite oxide lattice could participate in the OER via a lattice oxygen-mediated mechanism, providing possibilities for the development of alternative electrocatalysts that could overcome the scaling relations-induced limitations found in conventional catalysts utilizing the adsorbate evolution mechanism. Here we distinguish the extent to which the participation of lattice oxygen can contribute to the OER through the rational design of a model system of silicon-incorporated strontium cobaltite perovskite electrocatalysts with similar surface transition metal properties yet different oxygen diffusion rates. The as-derived silicon-incorporated perovskite exhibits a 12.8-fold increase in oxygen diffusivity, which matches well with the 10-fold improvement of intrinsic OER activity, suggesting that the observed activity increase is dominantly a result of the enhanced lattice oxygen participation.

This review of design and operating conditions of electrochemical CO2 reduction covers electrolytes, electrodes, reactors, temperature, pressure, and pH effects.

The slow activity of cathode materials is one of the most significant barriers to realizing the operation of solid oxide fuel cells below 500 °C. Here we report a niobium and tantalum co-substituted perovskite SrCo0.8Nb0.1Ta0.1O3−δ as a cathode, which exhibits high electroactivity. This cathode has an area-specific polarization resistance as low as ∼0.16 and ∼0.68 Ω cm2 in a symmetrical cell and peak power densities of 1.2 and 0.7 W cm−2 in a Gd0.1Ce0.9O1.95-based anode-supported fuel cell at 500 and 450 °C, respectively. The high performance is attributed to an optimal balance of oxygen vacancies, ionic mobility and surface electron transfer as promoted by the synergistic effects of the niobium and tantalum. This work also points to an effective strategy in the design of cathodes for low-temperature solid oxide fuel cells.

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). The ultrathin iron–cobalt MOF‐74 nanosheets prepared are only 2.6 nm thick. The sample enriched with surface coordinatively unsaturated metal sites, exhibits a significantly higher oxygen evolution reaction reactivity than bulk FeCo MOF‐74 particles and the state‐of‐the‐art MOF catalyst. It is believed that this 2dOSA could provide a new and simple way to synthesize various ultrathin MOF nanosheets for wide applications.