Cobalt-based nanosheet arrays as efficient electrocatalysts for overall water splitting†
Herein we report a simple electrochemical approach to synthesize cobalt-based nanosheet arrays as efficient and robust electrocatalysts for overall water splitting in alkaline electrolytes. The Co nanosheet array and CoFeBO nanosheet array are electrochemically deposited on Ni foam electrodes, which are able to drive a large current density at low overpotentials, and offer stable operation under heavy-loading conditions over an extended period, exceeding the performance of Pt/C and IrO2. To the best of our knowledge, the CoFeBO NS‖Co NS couple is currently the most active and stable non-noble electrocatalyst pair for overall water splitting in alkaline electrolytes. In addition, the facile synthesis method is suitable for designing and screening highly active and stable electrocatalysts with micro- and nano-structures.