Photocatalytic dissociation of CH3OH on ZnO(0001) surface

Photocatalysis of CH3OH on the ZnO(0001) surface has been investigated by using temperature-programmed desorption (TPD) method with a 266 nm laser light. TPD results show that part of the CH3OH adsorbed on ZnO(0001) surface are in molecular form, while others are dissociated. The thermal reaction products of H-2, CH3 center dot, H2O, CO, CH2O, CO2 and CH3OH have been detected. Experiments with the UV laser light indicate that the irradiation can promote the dissociation of CH3OH/CH3O center dot to form CH2O, which can be future converted to HCOO- during heating or illumination. The reaction between CH3OHZn and OHad can form the H2O molecule at the Zn site. Both temperature and illumination promote the desorption of CH3 center dot from CH3O center dot. The research provides a new insight into the photocatalytic reaction mechanism of CH3OH on ZnO(0001).