Rational doping regulation of Cu(OH)2 and Cu3P obtained by three-step continuous transformation for overall water splitting

Non-precious metal-based electrocatalysts are earth-abundant and cost-effective, which are expected to be alternative to traditional precious metal-based electrocatalysts. However, Cu-based electrocatalysts are plagued by low intrinsically catalytic activity for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) and deactivation at high potentials. Herein, the doping effect of 3d transition metal elements including Co, Cr, Fe, Mn, and Ni on the HER activity of Cu3P and the OER activity of CuOOH were theoretically determined by first principles calculations. Co-Cu3P and Co-CuOOH exhibit improved HER and OER activities, respectively, which are attributed to the decreasing electron transfer between the substrate and OH/H induced by the doping Co atom. Experiments confirmed that Co-Cu(OH)2 and Co-Cu3P yield overpotentials of 242.6 mV and 78.8 mV at a current density of 10 mA cm- 2 for OER and HER, respectively. A working voltage of 1.54 V at a current density of 10 mA cm- 2 was achieved for a Co-Cu(OH)2 || Co-Cu3P electrolyzer, comparable with that of the commercial RuO2/CF || Pt/C/CF. These findings show the enormous potential of theory-guided rational design of electrocatalysts, providing a new pathway to develop high-performance electrocatalysts.