Stabilizing Metallic Cu0 on the Surface of m-TiO2 for Photocatalytic H2 Production

Dodecanethiol was introduced as a protective agent to stabilize the in situ generated Cu-0 species on the surface of mesoporous TiO2 (m-TiO2). The as-produced samples were characterized by XRD, XPS, HRTEM and HADDF-STEM. It is noteworthy that only Cu-0 species were detected in these samples. The system thus served as an excellent model to investigate Cu-0-incorporated m-TiO2. Photocatalytic measurements suggested that the Cu-0 species could greatly enhance the photocatalytic H-2-evolution activity of m-TiO2 in formaldehyde solution. Moreover, we found that the activity depends on the concentration of Cu-0. The maximum H-2 evolution rate of 725 mu mol.h(-1).g(-1) is obtained on 1.0% Cu/m-TiO2, with average Cu-0 particle size of (4.2 +/- 0.9) nm. It is interesting to find that in our case, the molar ratio of produced H-2 to CO2 is 2:1, which indicates the involvement of H2O as hydrogen source.