Simultaneous in situ reduction and embedment of Cu nanoparticles into TiO2 for the design of exceptionally active and stable photocatalysts

Abstract

Efficient charge separation for a photocatalyst can be realized via addition of a co-catalyst, whereby most conventional techniques, i.e., deposition–precipitation, photoreduction, hydrothermal and vapour phase deposition result typically in surface loading effects. Moreover, the loading amount is deliberately kept nominal (below 10 wt%) as excessive loading causes both agglomeration and light blocking issues which limit the performance and stability of the photocatalyst. This work demonstrates one-pot in situ synthesis towards interdispersion and inclusion of a high concentration (Cu : TiO₂ weight ratio > 1) of a Cu NP co-catalyst into TiO₂ nanosheets without compromising its critical dispersivity and light absorption properties. The exceptional photocatalytic H₂ performance of 16.1 ± 0.35 mmol g⁻¹ h⁻¹ stems from the embedment and confinement of the small Cu NPs within the TiO₂ matrix which facilitates a shorter diffusion distance, thereby increasing the number of electrons available for catalytic reactions. Thus, this work highlights a facile approach towards optimal interfacing of the hybrid catalyst constituents to mitigate the limited interfacial contact and charge transfer challenges commonly faced in photocatalyst design.