Strong electronic coupling induced by synergy of dopant and interface in Ru-Ni3S2/NixPy to boost efficient water splitting

Abstract

It is challenging to fabricate high-efficiency and low-cost bifunctional electrocatalysts for water splitting. Herein, a high-performance nickel-based catalyst, Ru-Ni3S2/NixPy, was constructed via heteroatom doping and interface engineering. The synergy of Ru-doping and sulfide-phosphide heterointerfaces induced the ultrastrong electronic coupling on the catalyst surface, which effectively regulated electronic densities of the catalyst, improved intrinsic catalytic activities, and resulted in the excellent HER and OER bifunctional performances. In alkaline medium, it only required the OER overpotential of 244 mV for the as-prepared Ru-Ni3S2/NixPy catalyst to achieve 100 mA∙cm−2 and the HER overpotential of 51 mV to reach 10 mA∙cm−2. And only a voltage of 1.46 V was required to generate 10 mA∙cm−2 in the Ru-Ni3S2/NixPy(+,-) cell. Furthermore, the as-prepared Ru-Ni3S2/NixPy catalyst exhibited a long-term durability for water splitting. The DFT calculations indicated that the ultrastrong electronic coupling was primarily attributed to the aggregation of electrons around heterointerfaces and the excellent catalytic performance was due to effectively adjusting the adsorption of intermediates on active sites. This work is helpful for developing an effective strategy to fabricate high-performance catalysts.