Nickel/cobalt bimetallic phosphides derived metal-organic frameworks as bifunctional electrocatalyst for oxygen and hydrogen evolution reaction

Abstract

The construction of efficiently non-noble metal bifunctional electrocatalysts for both oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) is a major challenge for renewable energy generation. Here, considering the synergistic effect of differently metal sites and excellent electrocatalytic activities of bimetallic phosphides, the hybrids of NiCo bimetallic phosphides (NiCo–P) are prepared by one-step phosphorization of NiCo metal-organic frameworks (NiCo-BDC) as bifunctional electrocatalysts for water splitting. Benefiting from the unique porous structure and synergistic effect of Ni2P and Co2P in bimetallic phosphides system, Ni1Co1–P hybrid exhibits outstanding electrocatalytic activities for both OER and HER, with small overpotentials 343 mV (OER) and 169 mV (HER) at a current density of 10 mA cm−2 in alkaline conditions, respectively, which compares to monometallic phosphides (Ni–P and Co–P) and Ni–P + Co–P sample, illustrating the existence of Ni2P/Co2P interface as an essential requirement to achieve the synergistic effect and the improved catalytic activities in NiCo–P system. This work provides a general strategy to design more efficient multicomponent electrocatalysts.