In-situ generated CQDs-doped Ni(OH)2 nanosheets with high photoelectric activity on nickel foam for efficient hydrogen evolution reaction in alkaline solution

It is of great significance for a clean energy system to develop novel non-noble catalysts toward the alkaline hydrogen evolution reaction (HER). Herein, CQDs-doped Ni(OH)2 nanosheets generated on nickel foam were fabricated by a feasible method using Ni-MOF as precursor. Notably, the alkali etching treatment can open the spatial structure of Ni(OH)2 and expose more active sites, thereby improving the electrocatalytic active surface area. Meanwhile, introduced CQDs can be acted as the charge carrier and accelerate the charge transfer. As a result, the Ni(OH)2-CQDs nanosheets showed excellent electrocatalytic performance in HER under alkaline condition, and an overpotential of 101 mV for OER over Ni(OH)2-CQDs/NF electrode can be realized at a current density of 10 mA/cm2. More significantly, embedding CQDs can effectively boost the photocatalytic activity of Ni(OH)2. Thus, light radiation can enhance the performance of Ni(OH)2-CQDs/NF electrode in HER, and the overpotential of Ni(OH)2-CQDs/NF electrode for HER can reduce to 90 mV under light irradiation. Furthermore, the Ni(OH)2-CQDs/NF electrode displayed great HER stability, and the possible mechanism of photo-assisted electrochemical HER was also proposed. All in all, current work will share some valuable insights into preparation and application of catalysts in HER.