Valence-modified selenospinels as ampere-current-bearing oxygen evolution catalysts

Industrial water electrolysis requires highly-active and ampere-current-bearing oxygen evolution reaction (OER) catalysts, but achieving such a large operating current density at low overpotentials in available OER catalysts still remains a grand challenge. Herein, we present a new type of high-valence metal modified selenospinels (Mn-CuCo2Se4) as large-current-density OER catalysts. The optimal Mn-CuCo2Se4 exhibits prominent OER activity with overpotentials of 293 and 345 mV to achieve 500 and 1000 mA cm−2, respectively, and displays large mass activity, high turnover frequency and robust stability in alkaline media. Using in situ X-ray absorption spectroscopies, we observe that a surface active layer of oxyhydroxide-like phase with contracted CoCo distance was evolved during the OER, which is responsible for the highly-active large-current-density activity. This work may open a new arena for the screening of large-current-density OER catalysts based on the wide variety of spinels compounds.