In situ synthesis of novel Cu₂CO₃(OH)₂ decorated 2D TiO₂ nanosheets with efficient photocatalytic H₂ evolution...

Semiconductor-based photocatalytic hydrogen evolution from water with earth-abundant and low cost co-catalysts has attracted much attention. Herein, novel Cu₂(OH)₂CO₃ decorated 2D TiO₂ nanosheets for photocatalytic water splitting were synthesized by a facile in situ synthetic method. The chemical and photophysical properties of Cu₂(OH)₂CO₃/TiO₂ nanosheets were investigated by X-ray diffractometry (XRD), transmission electron microscopy (TEM), UV-vis diffusion reflectance spectroscopy (DRS), X-ray photoelectron spectroscopy (XPS) and cyclic voltammetry (CV) analysis. At an optimal Cu₂(OH)₂CO₃ loading content of 1.5 mol%, the hybrid photocatalyst delivers a high photocatalytic H₂ production rate of 1555.07 μmol g^-1 h^-1. Such enhanced photocatalytic activity is attributed to tight interfaces formed between Cu₂(OH)₂CO₃ nanoparticles and TiO₂ nanosheets, which play a vital role in the separation of photo-excited carriers, and the formation of active Cu¹⁺ and Cu⁰ species can also benefit the charge separation process by reducing the over-potential of water reduction. Based on the above results, a possible mechanism is proposed and further verified using photoluminescence (PL) spectra. This work may provide more insight into the synthesis of novel Cu₂(OH)₂CO₃/TiO₂ nanosheets with high photocatalytic H₂ evolution activity for solar-to-chemical conversion and utilization.