Elemental Engineering of High-Charge-Density Boron in Nickel as Multifunctional Electrocatalysts for Hydrogen Oxidation and Water Splitting
Tong Zhang, Fuzhan Song, Yuqin Qian, Hong Gao, Jeremy Shaw, Yi Rao
Abstract
The development of efficient and earth-abundant multifunctional electrocatalysts is challenging yet critical for clean energy systems. Herein, we present the development of a heteroatom B-doping approach, namely, B-doped Ni (B-Ni), for multifunctional electrocatalysis. The B-Ni catalysts exhibited multifunctional activities in an alkaline solution, including the hydrogen evolution reaction (HER), oxygen evolution reaction (OER), and hydrogen oxidation reaction (HOR). The B-Ni catalysts, as both the cathode and the anode, showed outstanding water splitting performance with cell voltages of 1.62 and 1.74 V versus reversible hydrogen electrode (RHE) to achieve 10 and 100 mA cm–2, respectively. Furthermore, the B-Ni catalysts produced an HOR current density of 0.85 mA cm–2 at 0.1 V versus RHE. Density functional theory (DFT) calculations showed that the doped B atom can extract electrons from its adjacent Ni site, resulting in increased charge densities on the B site and a loss of charge densities on the surrounding Ni atoms. Such charge redistribution is favorable to the HOR and HER processes. The heteroatom-doping approach of the B-Ni catalyst provides an alternative strategy for the development of earth-abundant electrocatalysts in both energy storage and conversion.