Heteroatom Engineering\nin Earth-Abundant Cobalt Electrocatalyst\nfor Energy-Saving Hydrogen Evolution Coupling with Urea Oxidation

The development of multifunctional electrocatalysts with\nhigh performance\nfor electrocatalyzing urea oxidation-assisted water splitting is of\ngreat significance for energy-saving hydrogen production. In this\nwork, we demonstrate a novel heteroatom engineering strategy for development\nof B-doped Co as a multifunctional electrocatalyst for the hydrogen\nevolution reaction (HER), oxygen evolution reaction (OER), and urea\noxidation reaction (UOR). Density functional theory (DFT) results\nsuggest that a B dopant can efficiently adjust the electron reconstruction\nof the exposure of Co sites nearby and facilitate electron transfer,\nresulting in an optimal d-band center along with a lower Gibbs free\nenergy barrier. Ultimately, the obtained B–Co exhibits pH-universal\nHER properties in various electrolytes. A highly efficient HER performance\nwith overpotentials as low as 27, 163, and 430 mV to −10, −100,\nand −500 mA cm<sup>–2</sup> in 1.0 M KOH, respectively,\nis observed for the B–Co electrode. More importantly, the UOR-assisted\nelectrolyzer only requires a voltage input of 1.55 V to produce the\ncurrent densities of 50 mA cm<sup>–2</sup>, resulting in a\n200 mV saving-energy potential compared to water electrolysis, demonstrating\nits high efficiency of hydrogen production in industrial applications.