Modulating the electron interaction of Cu-Ni hybrid sites for boosting photocatalytic hydrogen evolution over Al-doped SrTiO₃

Cocatalysts play a pivotal role in enhancing the efficiency of photocatalytic water splitting. In this study, we introduced a novel and straightforward pre-impregnation strategy to anchor a CuNi dual cocatalyst onto the surface of Al-doped SrTiO3 (Al-STO), coupled with photodeposition. This approach led to a remarkable 11.07fold (77.5 mu mol/h) increase in hydrogen evolution performance compared to the conventional photodeposition method for decorating with CuNi dual cocatalysts. Not only that, after the 18 h cycle experiment, the catalyst still maintains high activity and high stability similar to that of precious metals, which overcomes the defects of poor stability and short life of non-precious metals. This strategy capitalizes on the pre-adsorption of cocatalyst precursor ions on the Al-STO support via impregnation, enhancing both the adsorption energy and capacity between the precursor ions and the active sites. Detailed characterizations have revealed a strong electronic interaction within the Cu-Ni structure and improved interfacial coupling between CuNi and Al-STO. This not only significantly promotes charge separation and transfer but also provides a plethora of active sites for the photocatalytic generation of H2. Moreover, extensive theoretical calculations have provided deep insights into the reaction mechanism of the CuNi system and elucidated the reasons behind the varying degrees of activity enhancement across different cocatalyst architectural systems.