Single‐Crystal Cobalt Phosphate Nanosheets for Biomimetic Oxygen Evolution in Neutral Electrolytes

Coupling Magnetic Single-Crystal Co2 Mo3 O8 with Ultrathin Nitrogen-Rich Carbon Layer for Oxygen Evolution Reaction

Transition-metal oxides as electrocatalysts for the oxygen evolution reaction (OER) provide a promising route to face the energy and environmental crisis issues. Although palmeirite oxide A₂ Mo₃ O₈ as OER catalyst has been explored, the correlation between its active sites (tetrahedral or octahedral) and OER performance has been elusive. Now, magnetic Co₂ Mo₃ O₈ @NC-800 composed of highly crystallized Co₂ Mo₃ O₈ nanosheets and ultrathin N-rich carbon layer is shown to be an efficient OER catalyst. The catalyst exhibits favorable performance with an overpotential of 331 mV@10 mA cm^-2 and 422 mV@40 mA cm^-2 , and a full water-splitting electrolyzer with it as anode catalyst shows a cell voltage of 1.67 V@10 mA cm^-2 in alkaline. Combined HAADFSTEM, magnetic, and computational results show that factors influencing the OER performance can be attributed to the tetrahedral Co sites (high spin, t₂ ³ e⁴ ), which improve the OER kinetics of rate-determining step to form *OOH.

Spontaneous Synthesis of Silver-Nanoparticle-Decorated Transition-Metal Hydroxides for Enhanced Oxygen Evolution Reaction

The fabrication of metal-supported hybrid structures with enhanced properties typically requires external energy input, such as pyrolysis, photolysis, and electrodeposition. In this study, silver-nanoparticle-decorated transition-metal hydroxide (TMH) composites were synthesized by an approach based on a spontaneous redox reaction (SRR) at room temperature. The SRR between silver ions and TMH provides a simple and facile route to establish effective and stable heterostructures that can enhance the oxygen evolution reaction (OER) activity. Ag@Co(OH)_x grown on carbon cloth exhibits outstanding OER activity and durability, even superior to IrO₂ and many previously reported OER electrocatalysts. Experimental and theoretical analysis demonstrates that the strong electronic interaction between Ag and Co(OH)₂ activates the silver clusters as catalytically OER active sites, effectively optimizing the binding energies with reacted intermediates and facilitating the OER kinetics.