Ni doping engineering of ultrathin cobalt pyrophosphate nanosheets for boosted oxygen evolution in alkaline media

Abstract Development of high-performance non-noble electrocatalysts is highly desirable for practical oxygen evolution reaction (OER) implementation. Herein, a series of nickel-doped cobalt pyrophosphate (Ni–Co 2 P 2 O 7 ) nanosheet composites were successfully fabricated via a straightforward one-pot hydrothermal route. The synergistic integration of Ni heteroatom doping and ultrathin nanosheet structure effectively optimizes the electrochemical properties of the catalyst. By regulating the Ni doping content, the optimized (Ni 0.06 Co 0.94 ) 2 P 2 O 7 catalyst exhibits superior OER activity and durable cycling stability in alkaline electrolytes. Appropriate Ni doping can significantly modulate the surface electronic structure, increase accessible active sites, generate plentiful catalytic sites, and expedite OER kinetics. As verified by electrochemical measurements, the (Ni 0.06 Co 0.94 ) 2 P 2 O 7 catalyst achieves a small overpotential of 290 mV at the benchmark current density of 10 mA cm −2 . This work elucidates the positive regulatory effect of nickel heteroatom doping on the OER performance of cobalt pyrophosphate, and provides a new perspective for the rational design of high-efficiency non-noble electrocatalysts.