Promotion of photocatalytic steam reforming of methane over Ag0/Ag+-SrTiO3

Methane (CH4) is not only used as a fuel but also as a promising clean energy source for hydrogen generation. The steam reforming of CH4 (SRM) using photocatalysts can realize the production of syngas (CO + H-2) with low energy consumption. In this work, Ag-0/Ag+-loaded SrTiO3 nanocomposites were successfully prepared through a photodeposition method. When the loading amount of Ag is 0.5 mol%, the atom ratio of Ag+ to Ag-0 was found to be 51:49. In this case, a synergistic effect of Ag-0 and Ag+ was observed, in which Ag-0 was proposed to improve the adsorption of H2O to produce hydroxyl radicals and enhance the utilization of light energy as well as the separation of charge carriers. Meanwhile, Ag-0 was regarded as the reduction reaction site with the function of an electron trapping agent. In addition, Ag+ adsorbed the CH4 molecules and acted as the oxidation reaction sites in the process of photocatalytic SRM to further promote electron-hole separation. As a result, 0.5 mol% Ag-SrTiO3 exhibited enhancement of photocatalytic activity for SRM with the highest CO production rate of 4.3 mmol g(-1) h(-1), which is ca. 5 times higher than that of pure SrTiO3. This work provides a facile route to fabricate nanocomposite with cocatalyst featuring different functions in promoting photocatalytic activity for SRM. (c) 2019 Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences. Published by Elsevier B.V. All rights reserved.