Doping-induced facet transformation boosts water oxidation activity of cobalt carbonate hydroxide hydrate

Rational engineering of non-noble metal catalysts with exposed highly active facets for water splitting is desirable yet remains greatly challenging. Herein, we report a doping-induced facet transformation strategy to prepare single-crystalline cobalt carbonate hydroxide hydrate (CCOH) nanowires with high oxygen evolution reaction (OER) activity. Specifically, Cu doping induces the CCOH nanowires to grow along the (020) direction, whereas nanowires without Cu dopant grow along the (121) direction. Density functional theory calculations reveal that compared with the (121) surface, the (020) surface of CCOH has higher intrinsic OER activity due to different atomic arrangements and coordination. As a result, the Cu-doped (020)-faceted CCOH nanowire arrays exhibit outstanding OER performances with a low overpotential of 210 mV at 10 mA cm−2 and a Tafel slope of 67 mV dec−1 in alkaline medium, as well as extremely long-term durability over 36 h. Our findings demonstrate that doping-induced facet engineering is an effective strategy to design and develop highly active catalysts.