Co-catalyst and heterojunction dual strategies to induce photogenerated charge separation for efficient hydrogen...

The construction of heterojunctions is considered to be an important means to promote efficient electron-hole separation in photocatalysts. However, photocatalysts have poor light absorption ability and a relatively small chance of capturing H⁺, and the stability needs to be improved. In this work, a non-precious metal co-catalyst Cu₃P was introduced for the successful construction of p-n heterojunctions from NiO and CdS to promote charge separation while expanding the light absorption capacity and increasing the chance of H⁺ capture, thus enhancing the photocatalytic hydrogen precipitation activity and stability. The overall photocatalytic performance was improved by continuously optimizing the loading of NiO and Cu₃P. Satisfyingly, using a 5 W LED lamp as the light source, the hydrogen evolution rate of the composite photocatalyst 15NC@Cu-10 in 10 vol% lactic acid solution is 15 612.0 μmol h^-1 g^-1, and the AQE reaches 10.4%. XPS analysis confirmed the direction and path of electron transfer. This synergistic strategy of co-catalyst modification of p-n heterojunctions provides a unique insight into the preparation of efficient and stable photocatalysts and also expands the applications of MOFs and their derivatives in the field of photocatalysis.