CO methanation promoted by UV irradiation over Ni/TiO2

Abstract

Thermo-catalytic CO methanation has been widely investigated as an attractive strategy for the removal of CO in H2-rich stream. In this paper, UV irradiation was introduced into the system of thermo-catalytic CO methanation over a noble-metal-free Ni/TiO2 catalyst. It is found that UV irradiation can remarkably promote the CO conversion and CH4 selectivity, as well as an excellent catalytic stability under the thermo-catalytic reaction conditions. Results of XPS, FT-IR, and TPO measurements for the Ni/TiO2 catalyst indicate that upon UV light irradiation, the photo-generated electrons are transferred from the TiO2 support to the adjacent Ni sites, and causes the Ni sites with increased surface electron density which subsequently enhances the adsorption and activation of CO molecules at Ni sites, and ultimately promotes the catalytic performance of CO methanation. This result shows that photo-excitation of TiO2 can act as an electron donor to promote the thermo-catalytic performance of CO methanation over Ni/TiO2.