Cobalt doping boosted electrocatalytic activity of CaMn3O6 for hydrogen evolution reaction

The development of earth-abundant-metal-based electrocatalysts with high efficiency and long-term stability for hydrogen evolution reaction (HER) is crucial for the clean and renewable energy application. Herein, we report a molten-salt method to synthesize Co-doped CaMn3O6 (CMO) nanowires (NWs) as effective electrocatalyst for HER. The as-obtained CaMn3−xCoxO6 (CMCO) exhibits a small onset overpotential of 70 mV, a required overpotential of 140 mV at a current density of 10 mA·cm−2, a Tafel slope of 39 mV·dec−1 in 0.1 M HClO4, and a satisfying long-term stability. Experimental characterizations combined with density functional theory (DFT) calculations demonstrate that the obtained HER performance can be attributed to the Co-doping which altered CMO’ s surface electronic structures and properties. Considering the simplicity of synthesis route and the abundance of the pertinent elements, the synthesized CMCO shows a promising prospect as a candidate for the development of earth-abundant, metal-based, and cost-effective electrocatalyst with superior HER activity. Our results also establish a strategy of rational design and construction of novel electrocatalyst toward HER by tailoring band structures of transition metal oxides (TMOs).