Heteroatom Engineering in Earth-Abundant Cobalt Electrocatalyst for Energy-Saving Hydrogen Evolution Coupling with Urea Oxidation

Abstract

The development of multifunctional electrocatalysts with high performance for electrocatalyzing urea oxidation-assisted water splitting is of great significance for energy-saving hydrogen production. In this work, we demonstrate a novel heteroatom engineering strategy for development of B-doped Co as a multifunctional electrocatalyst for the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and urea oxidation reaction (UOR). Density functional theory (DFT) results suggest that a B dopant can efficiently adjust the electron reconstruction of the exposure of Co sites nearby and facilitate electron transfer, resulting in an optimal d-band center along with a lower Gibbs free energy barrier. Ultimately, the obtained B-Co exhibits pH-universal HER properties in various electrolytes. A highly efficient HER performance with overpotentials as low as 27, 163, and 430 mV to -10, -100, and -500 mA cm^-2 in 1.0 M KOH, respectively, is observed for the B-Co electrode. More importantly, the UOR-assisted electrolyzer only requires a voltage input of 1.55 V to produce the current densities of 50 mA cm^-2, resulting in a 200 mV saving-energy potential compared to water electrolysis, demonstrating its high efficiency of hydrogen production in industrial applications.

Keywords: Earth-abundant electrocatalysts; Heteroatom engineering; Hydrogen evolution; Multifunctional electrocatalyst; Water splitting.