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

Highlights: • The unique hierarchically array structural CF@CT-Ni₄Mo NS electrodes are synthesized. • The CF@CT-Ni₄Mo NS electrode exhibits perfect activity toward both HER and OER. • The alkaline electrolyzer equipped with CF@CT-Ni₄Mo NS is easily driven by a solar cell in outdoor environment. -- Abstract: Herein, a unique hierarchically array structural electrode, composed of Ni₄Mo alloy nanosheets covering on carbon tube arrays on carbon fiber cloth (CF@CT-Ni₄Mo 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-Ni₄Mo 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-Ni₄Mo 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.