Uniform dispersion of CuO nanoparticles on mesoporous TiO2 networks promotes visible light photocatalysis

Here, we focus our efforts on synthesizing a uniform dispersion of CuO nanoparticles on mesoporous TiO2 networks for the first time. H2PtCl6 was added through a photocatalytic reaction to produce 0.5% Pt/CuO–TiO2 nanocomposites. XRD patterns confirmed that the prepared TiO2 formed the anatase phase. TEM images showed close contacts between CuO and TiO2 with 5–10 nm particle sizes. One of the advantages of the synthesized mesoporous CuO–TiO2 nanocomposites was the high pore volume (0.540 cm3 g−1) and large surface area (300 m2 g−1). The H2 evolution over the mesoporous 3 wt% CuO–TiO2 nanocomposites using a glucose hole scavenger [10 vol%] was determined to be ~13000 μmol/g, a value that was 1300 times greater than that of mesoporous TiO2. The H2 evolution rate was increased by up to 1300 and 20 times for 3 wt% CuO–TiO2 and 0.1 wt% CuO–TiO2 nanocomposites, respectively, compared with that of mesoporous TiO2. The increase in H2 evolution over mesoporous CuO–TiO2 nanocomposites was explained by the increased light harvesting capacity, high glucose molecule diffusion and efficient charge carrier separation. Moreover, the construction of a heterostructure with a p–n CuO–TiO2 heterojunction expedited the separation of charge carriers and promoted the evolution of H2. In addition, H2 evolution was substantially increased by the synergistic effects of Pt and CuO on the mesoporous TiO2 networks. Photoelectrochemical and photoluminescence measurements were employed to prove the H2 evolution mechanism over the CuO nanoparticles deposited on the mesoporous TiO2 networks.