Reduction-induced surface reconstruction to fabricate cobalt hydroxide/molybdenum oxide hybrid nanosheets for promoted oxygen evolution reaction

Electrocatalysts for oxygen evolution reaction (OER) have received substantial interests owing to its critical role in boosting water electrolysis for hydrogen production, and designing highly efficient and durable OER catalysts based on earth-abundant elements is of great importance in replacing noble metal-based catalysts. Herein, a facile reduction-induced surface reconstruction process was proposed for fabricating cobalt hydroxide/molybdenum oxide hybrid nanosheets with high porosity, rough surface and facile charge transport behavior. Benefitted from the structural merits, the highly porous α-Co(OH)2/Mo9O26 hybrid nanosheets exhibit an ultralow overpotential of 279 mV for achieving a 10 mA cm−2 current density and a high current density of 225.2 mA cm−2 at 1.8 V vs. RHE. In addition, a remarkable normalized current density of 11.9 A F-1 can be identified at η = 400 mV, which is much larger than previously reported Co-based catalysts and even benchmarking RuO2 and IrO2. Moreover, for CoMoO-r displays stable OER activity towards long-term operation with no performance degradation but obvious enhancement even for 72 h. The high OER activity combined with the excellent stability makes the hybrid catalyst a promising candidate for commercial water splitting.