Top-Down Preparation of Active Cobalt Oxide Catalyst

Cobalt oxide is a cheap catalyst for the oxygen evolution reaction; however, the low activity limits its practical application. Herein we report the preparation of a highly active Co₃O₄ catalyst via a top-down process, namely, laser fragmentation. The fierce laser irradiation generates fine and clean nanoparticles with abundant oxygen vacancies which simultaneously improve the adsorption energy and electrical conduction. As a result, the catalytic performance of the product reaches the top level of cobalt oxide, even outperforming the noble-metal catalyst, RuO₂

Copper Nanoparticles with Abundant Defects as a pH-Universal Catalyst for Hydrogen Evolution Reaction

The development of low-cost, high-activity, and pH universal catalysts is essential in hydrogen evolution reaction (HER) via industrial electrolysis of water. Here, we report the rapid and scalable preparation of defect-rich copper catalysts as electrocatalysts for all-pH HER by electric discharge in liquid (EDL) technology. The defects upshift the d-band center of copper, improve water dissociation and hydrogen adsorption, and ultimately improve the intrinsic catalytic activity. Thus, the overpotentials of Cu catalysts reach 180 mV in 0.5 M H2SO4, 269 mV in 1 M PBS, and 152 mV at 10 m A cm–2 in 1 M KOH. In addition, the Cu catalysts also exhibit lower overpotentials at high current density (1 A cm–2), superior to commercial Pt/C in neutral and alkaline solutions. Our work demonstrates that the EDL is a powerful technique for preparing metallic catalyst, and introducing defects into copper nanoparticles provides a versatile and friendly strategy for improving intrinsic catalytic performance