Investigating the photoactivity of Cu2O-TiO2 (Home Prepared) composites for H2 production by photoreforming under natural solar light in a pilot plant photoreactor

Home-prepared TiO2 containing an anatase/rutile mixture was coupled with different Cu2O amounts by the ball milling method technique. The samples were characterized by UV-Vis diffuse spectroscopy (DRS), specific surface area (SSA) determination, photoluminescence (PL) and Raman spectra, X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), Electron Paramagnetic Resonance (EPR) and photoelectrochemical measurements. The photocatalytic activity was studied for H2 production under natural solar light irradiation in a pilot plant reactor in the presence of different sacrificial agents. An effective heterojunction that enhanced the charge transfer processes, was formed between the components, as confirmed by photoluminescence spectra. 3 %Cu2O-TiO2 was the most active photocatalyst and the presence of Cu2O (instead of the noble metals generally used) was efficient for H2 production with 62 mmol obtained after 5 h (equivalent to ca. 5 mmol g−1 h−1) of solar irradiation starting from glycerol, which yielded the highest H2 amount with respect to the other sacrificial agents. Copper was present in different oxidation states and a moderate amount of leaching of Cu species was found. Holes, OH• and O2•− radicals were the main active species for glycerol degradation, while a higher availability of photoproduced electrons was beneficial for H2 production.