Construction of a heterojunction between Ni/Al layered double oxides and CdS quantum dots for efficient photocatalytic hydrogen production.

The Ni/Al layered double oxide (Ni/Al-LDO) is a promising photocatalyst because of the high surface area and abundant active sites. However, the application of Ni/Al-LDO for photocatalytic hydrogen evolution is hindered by the unclarity of the optimized microstructure and limited light absorption. In this work we report the structural evolution from Ni/Al layered double hydroxides (Ni/Al-LDH) to Ni/Al-LDO, which is able to achieve a precise regulation of the layered structure with abundant acid sites for photocatalysis. Further, CdS quantum dots (QDs) are in-situ grown on the sheet-like Ni/Al-LDO to obtain a close contact 0D/2D CdS-Ni/Al-LDO heterojunction. CdS-Ni/Al-LDO exhibits a hydrogen evolution efficiency of 20.3 mmol/g/h and an apparent quantum yield (AQY) of 22.2 % at a wavelength of 450 nm. The superior performance is attributed to the synergistic effects of abundant Lewis and Brønsted acid sites of Ni/Al-LDO, the layered structure with a high specific surface area and the heterojunction between Ni/Al-LDO and the CdS QDs.