NixFe1-xB Nanoparticles Self-Modified Nanosheets as Efficient Bifunctional Electrocatalysts for Water Splitting: Experiments and Theories
Developing high-efficient, stable, and inexpensive electrocatalysts for both hydrogen evolution reactions (HER) and oxygen evolution reactions (OER) is the premise of achieving large-scale water splitting. Here, NixFe1-xB prepared by a facile borothermal reduction in molten salt is a robust bifunctional electrocatalyst for overall water splitting. The NixFe1-xB electrocatalyst achieves a current density of 10 mA cm−2 at overpotentials of 63.5 mV for HER and 282 mV for OER in 1 M KOH electrolyte, respectively. Density function theory (DFT) calculations suggest that the NixFe1-xB possesses lower absolute value of H* adsorption free energy (|ΔGH*|) than the primitive FeB and NiB, which is beneficial to improve the HER activity. Two identical NixFe1-xB electrodes are combined to form an alkaline electrolyzer, which achieves a current density of 10 mA cm−2 at 1.57 V for overall water splitting. This work provides an strategy to develop high-efficient transition metal borides catalysts for overall water-splitting.