Strawberry-like Co3O4-Ag bifunctional catalyst for overall water splitting

Abstract Water electrolysis has been proven as an effective means to produce clean hydrogen energy, and such a process can be accelerated by active bifunctional electrocatalysts for both hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, we adopted a laser ablation technique to prepare a strawberry-like catalyst with Co3O4 clusters embedded in Ag nanoparticles, realizing the ingenious mutual regulation of Co3O4 and Ag. The Co3O4 facilitates the water dissociation and optimizes the hydrogen adsorption of Ag by introducing tensile strain and low coordination number, resulting in a low HER overpotential of 51 mV at 10 mA cm-2. Meanwhile, the electron transfer from Co3O4 to Ag facilitates the oxidization of Co3O4 and improves the OER performance, leading to a low OER overpotential of 206 mV at 10 mA cm-2. Ultimately, an ultralow potential of 1.49 V for overall water splitting has been achieved at 10 mA cm-2, outperforming Pt/C+RuO2 couple.