Grain boundary density and electronic dual modulation of intermetallic Co2B by Fe doping toward efficient catalyst for oxygen evolution reaction

Developing the high-performance intermetallic bi–metal boride OER catalysts with a high density of grain boundaries and appropriate electronic structure is still a challenge. Herein, we synthesized an intermetallic (FexCo1−x)2B OER catalyst (GB-(FexCo1−x)2B) with controllable grain boundary densities by a facile ball-milling method. Benefiting from the modulation of both grain boundary density and electronic structure, the GB-(Fe0.66Co0.34)2B supported on reduced graphene oxide shows a low OER overpotential of 221 mV at a current density of 10 mA cm−2 and Tafel slope of 38.2 mV dec−1. The experimental and theoretical calculated methods demonstrate that the Fe introduction into the intermetallic Co2B catalyst can produce the higher grain boundary density and modulate the electronic structure, respectively. This work provides a promising insight in understanding the synergetic effects in bimetallic for GB-(FexCo1−x)2B systems and supports a new strategy to explore other efficient catalysts with a high density of grain boundaries.