Ni4Mo alloy nanosheets coating on carbon tube arrays as high-performance electrocatalyst toward overall water splitting.

• The unique hierarchically array structural CF@CT-Ni 4 Mo NS electrodes are synthesized. • The CF@CT-Ni 4 Mo NS electrode exhibits perfect activity toward both HER and OER. • The alkaline electrolyzer equipped with CF@CT-Ni 4 Mo NS is easily driven by a solar cell in outdoor environment. The unique hierarchically array structural CF@CT-Ni 4 Mo NS electrodes not only expose numerous active sites, but also promote charge, electrolyte and gas products transfer in the catalysis process. And the alkaline electrolyzer with CF@CT-Ni 4 Mo NS as both anode and cathode shows efficient performance, which can be easily driven by a commercial solar cell in general outdoor environment Herein, a unique hierarchically array structural electrode, composed of Ni 4 Mo alloy nanosheets covering on carbon tube arrays on carbon fiber cloth (CF@CT-Ni 4 Mo NS), is designed and synthesized. The facile structure not only exposes numerous active sites by enlarging specific surface areas, but also promotes gas products, mass and charge transfer in the catalysis process. Thanks to the reasonable electrode structure, as-prepared CF@CT-Ni 4 Mo NS electrode presents high catalytic activity with only requiring overpotentials of 40.8 mV and 261.4 mV to drive 20 mA cm −2 toward hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), respectively, in KOH (1.0 M) solution. Moreover, the alkaline electrolyzer with CF@CT-Ni 4 Mo NS electrodes as bifunctional catalysts can afford 20 mA cm −2 toward overall water splitting at a cell voltage of 1.52 V. More importantly, a commercial solar cell can be used to drive the alkaline electrolyzer in general outdoor environment.