Efficient hydrogen generation of vector Z-scheme CaTiO3/Cu/TiO2 photocatalyst assisted by cocatalyst Cu nanoparticles

Abstract

Herein, the CaTiO3/Cu/TiO2 all-solid-state Z-scheme heterojunction is successfully designed via Cu nanoparticles situating at the interface between CaTiO3 and TiO2 with a new synthesis route. Interestingly, TiO2 nanosheets are generated in-situ on the surface of CaTiO3 in the second step hydrothermal reaction. The lifetimes of photoexcited carriers, photoluminescence emission spectra and transient photocurrent response tests have confirmed that the efficient Z-scheme charge transmission path of the CaTiO3/Cu/TiO2 is beneficial to facilitate the separation of photogenerated carriers and reduce their recombination efficiency. As expected, the hydrogen generation rate of CaTiO3/Cu/TiO2 is increased to 23.550 mmol g-1h−1 with the appropriate amount of copper loading, which is about 981 times and 93 times higher than that of pristine CaTiO3 (0.024 mmol g-1h−1) and CaTiO3/TiO2 (0.253 mmol g-1h−1), respectively. Furthermore, the CaTiO3/Cu/TiO2 sample shows good stability in cycle experiments. Particularly, experimental results show that the non-noble metal Cu nanoparticles can be an effective electron mediator. And these merits strongly demonstrate that the CaTiO3/Cu/TiO2 composites have potential application in photocatalytic field. This study can provide fundamental guidance for designing rationally efficient non-noble metal vector Z-scheme system photocatalysts with outstanding photocatalytic H2 generation performance.