Iron-induced lattice distortion generally boots the graphene-supported nickel phosphide nanoparticles catalysis for efficient overall water splitting

Abstract

Rational design of high-efficient, low-cost and stable bifunctional electrocatalysts is necessary but challenging for water electrolysis. Transition metal phosphides (TMPs) with rich redox properties are considered to be the most promising substitutes for noble-metal materials but with aggregation and poor intrinsic electrical conductivity. Herein, we report an ultra-fast and controllable microwave strategy for synthesizing Fe-doped nickel phosphide on reduced graphene oxide (Fe-Ni12P5/rGO) as a highly active bifunctional electrocatalyst for both hydrogen and oxygen evolution reactions (HER and OER). It is noteworthy that Fe introduction can significantly cause the lattice distortion of Ni12P5 and lead to the increase of electrocatalytic active sites and modulation of the electronic structure of each catalytic center. Benefiting from the highly active Fe-Ni12P5 nanoparticles and two-dimensional graphene conductive network, the as-fabricated Fe-Ni12P5/rGO shows excellent electrocatalytic activity for HER and OER with good stability. In addition, an overall water splitting device with Fe-Ni12P5/rGO as both the cathode and anode electrocatalysts requires only an extremely low cell voltage of 1.57 V to reach 10 mA cm−2, which is attractive among the latest research. This work provides a facile and effective approach for the design of high-performance transition metal-based electrocatalysts.