Controllable synthesis and phase-dependent electrocatalytic oxygen evolution performance of CoNiFe sulfide nanocubes

Abstract

The electrochemical oxygen evolution reaction (OER) highly depends on the phase structure of catalysts. Herein, the CoNiFe-based sulfides are fabricated by a surface decoration on NiFe Prussian blue analogue, followed by an evaporating sulfurization process. The as-formed metal sulfides have a nanocubic morphology and show a phase-dependent OER activity in alkaline electrolyte. The optimized catalyst possesses a remarkable activity and durability towards OER, featured by a low overpotential of 288 mV at 10 mA cm−2 and a small Tafel slope of 72 mV dec−1. The outstanding OER performance originates from the hierarchically porous architecture and interfacial coupling between CoS2 and (Ni,Fe)S2 phases. Our finding provides a promising strategy to develop advanced low-cost electrocatalysts with intriguing phase structure by producing the heterojunctions via post treatments on PBA such as surface modification and evaporation sulfidization.