In-situ reconstruction of self-supported amorphous Ni-Mo electrode for stable hydrogen evolution at large and intermittent current density.

• NiMo-Pi is obtained via a one pot hydrothermal reaction. • This self-supported cathode shows enhanced water reduction activity. • It responses quickly and robustly in a wide current range. • In-situ reconstruction of its surface enables high stability. Solar power drived water splitting for hydrogen production is pivotal for sustainable energy conversion. Yet, it is challenging to develop earth abundant, high active, and durable electrodes to catalyzing hydrogen evolution reaction (HER) under fluctuating solar electricity. Herein we report self-supprted NiMo phosphate (NiMo-Pi) electrodes, where amorphous NiMo-Pi with nanosheets-like structure grow directly on conductive Ni foam by a facile one-step hydrothermal treatment. The electronic structures of Ni and Mo are tuned by O and P in NiMo-Pi electrodes, resulting the down-shift of their d -band centers. NiMo-Pi electrodes offer high activity and stability for HER, delivering -100 and -500 mA cm−2 mg cat −1 with overpotentials of 343 and 461 mV, repectively. They also sustain long-term electrolysis at a constant industrial-level current density of 500 mA cm−2 and at dynamic current densities ranging from -10 to -1 000 mA cm−2. Their HER activity become higher after stability tests, benefitting from in-situ surface reconstruction. This reconstruction makes the surface rich in active higher-lying d -band centers. This work suggests that tuning the electronic structure of electrodes is an efficient way to design efficient and stable electrodes for HER under harsh conditions. [Display omitted] [ABSTRACT FROM AUTHOR]