Enhanced activity and stability of Co-Ni-P-B catalyst for the hydrogen evolution reaction via predeposition of Co-Ni on a Cu substrate

Abstract

In this work, the effect of a predeposited Co-Ni layer on the catalytic activity and long-term durability of the quaternary Co-Ni-P-B catalyst for the hydrogen evolution reaction (HER) is investigated. To study the effect of predeposition of the Co-Ni layer for the Co-Ni-P-B catalyst, both Co-Ni-P-B/Co-Ni/Cu and Co-Ni-P-B/Cu catalysts are prepared. The current density for HER of the Co-Ni-P-B/Co-Ni/Cu catalyst at −0.5 VRHE is 36.1% higher than that of Co-Ni-P-B/Cu in 0.5 M H2SO4 solution at 18 °C. This is because the porous morphology of the Co-Ni-P-B/Co-Ni/Cu catalyst leads to a 10.6% larger electrochemical surface area and higher atomic ratio for both the P and B contents, which act as a proton acceptor and a supplier of electrons to the d orbital of the transition metals, respectively, compared to Co-Ni-P-B/Cu on the catalytic surface. Furthermore, the Co-Ni-P-B/Co-Ni/Cu catalyst retains 94.5% of the catalytic activity during durability test of 1 h owing to its higher adhesion strength between the substrate and catalyst and rougher morphology, whereas the Co-Ni-P-B/Cu catalyst shows a retention of only 64.4%.