TiO2 Surface Hybridisation with Noble Metals (Ag and CuxO) for Solar De-NOx and VOC Removal

Indoor and outdoor air pollution remains a major health risk for human beings. Nitrogen oxides and volatile organic compounds are amongst the major pollutant found outdoor. Thus, actions to diminish such risks and to provide safer outdoor / indoor environment are required. In this research work, we have decorated the surface of TiO₂ with noble-metal oxides (Ag and/or Cu_xO) to improve the photocatalytic performances (removal of nitrogen oxides and benzene) under simulated solar-light irradiation. By means of advanced X-ray methods it has been shown that noble metals did not enter the TiO₂ crystal structure, although they retarded the anatase-to-rutile phase transition and crystal growth.

Photocatalytic activity was assessed in the gas-solid phase, monitoring the degradation of NO_x and benzene, using a lamp simulating the solar radiation. Results showed that TiO₂ modified with an Ag:Cu molar ratio equal to 1:1 (with Ag+Cu = 0.5+0.5 mol% = 1 mol%), was that exhibiting best de-NO_x and benzene removal performances.