Magnesium incorporation activates perovskite cobaltites toward efficient and stable electrocatalytic oxygen evolution

摘要

Cobalt-rich perovskite oxides play a paramount role in catalyzing oxygen evolution reaction(OER)on account of their acceptable intrinsic activity but are still challenging due to the high costs and undesired stability.In response to the defects,herein,the Mg-incorporated perovskite cobaltite SrCo_(0.6)Fe_(0.3M)g_(0.1)O_(3-δ)(SCFM-0.1)is proposed as a novel earth-abundant and durable OER electrocatalyst.A well-consolidated cubic-symmetry structure and more active oxygen intermediates are enabled upon Mg substitution.Hence,the optimized SCFM-0.1 perovskite oxide achieves prominent OER electrocatalytic performance,that is,a low overpotential of only 320 mV at 10 mA cm^(-2),a small Tafel slope of 65 mV dec^(-1),as well as an outstanding durability within 20 h,substantially outperforming that of the pristine SrCo_(0.7)Fe_(0.3)O_(3-δ)and benchmark Ba_(0.5)Sr_(0.5)Co_(0.8)Fe_(0.2)O_(3-δ)and IrO_(2) catalysts.The strong pHdependent behavior associated with lattice oxygen activation mechanism for SCFM-0.1 catalyst is also confirmed.This work paves a unique avenue to develop cost-effective and robust perovskite cobaltites for efficient OER electrocatalysis.