Corrosion engineering derived Ga doped CoSe2 nanosheets intrinsically active for oxygen evolution reaction

The development of active and robust oxygen evolution reaction (OER) electrocatalysts in alkaline media is of great value for high-efficiency hydrogen production through electrochemical water electrolysis. Heteroatom-doping and defect-introduction are critical strategies in activating OER electrocatalysts. Herein, a combined magnetron sputtering, Co–Ga alloying, dealloying and selenization strategy was adopted to realize Ga-doped CoSe2 nanosheets with enriched oxygen vacancies supported on stainless steel mesh (SSM) for OER. The as-obtained L-CoSe2/SSM exhibits remarkable OER performances with an ultralow overpotential of 227 mV at 10 mA cm−2, and small Tafel slope of 49.15 mV dec−1 in 1 M KOH. In addition, the catalyst displays negligible activity decay after more than 25 h of continuous operation. The enhanced OER performances of the L-CoSe2/SSM can be rationalized by plentiful oxygen vacancies, Ga doping, unique roughened nanosheets structure and substrate (SSM). The findings provide promising and controllable synthetic strategy for low-cost CoSe2 based electrocatalyst toward practical applications of water electrolysis. [Display omitted] •A novel strategy is developed to fabricate CoSe2/SSM electrocatalysts for OER .•L-CoSe2/SSM exhibits remarkable OER performance with ultralow overpotential.•The enhanced OER performance can be explained by oxygen vacancies and Ga doping.