Rational design of cobalt–chromium layered double hydroxide as a highly efficient electrocatalyst for water oxidation

Abstract

The design of a high performance, stable and cost-effective electrocatalyst for oxygen evolution is crucial for H₂ production from electrochemical water splitting. Here, as a dual-functional-site catalyst, cobalt–chromium layered double hydroxide (CoCr LDH) nanosheets are designed and synthesized, where Co²⁺ is the catalytically active site and Cr³⁺ is the charge transfer site. OER investigation of CoCr LDH is conducted for the first time. The CoCr LDH nanosheets have a high specific surface area of 151.78 m² g⁻¹ and exhibit outstanding OER activities, among the best of Co-based candidates. Accordingly, our catalyst affords a low onset potential of 1.47 V (vs. reversible hydrogen electrode, RHE) and a stable current density of 22.8 mA cm⁻² at 1.61 V (vs. RHE) for 12 h. The Tafel slope of CoCr LDH is 81.0 mV dec⁻¹, smaller than that of state-of-the-art RuO₂ (90.1 mV dec⁻¹). Therefore, the CoCr LDH nanosheets are promising OER catalysts.