Surface electronic state modulation promotes photoinduced aggregation and oxidation of trace CO for lossless purification of H2 stream

Abstract

Although photogenerated hydroxyl radicals can oxidize CO without H2 consumption, the nonselective collision severely lowers photocatalytic photon utilization. We here demonstrate that electronic state modification of TiO2 resulted from magnesium doping can promote hydroxyl radical generation by weakening the adsorption of oxygen species and facilitating semiconductor-cocatalyst interfacial electron transfer. Importantly, the partial deprivation of electronic cloud from cationic sites can strengthen σ-donation and π-backdonation that synergistically promote the electrostatic interaction for aggregating CO in the vicinity of semiconductor. The resulted photocatalyst thus exhibits growing superiority over common counterpart in target reaction as CO concentration lowers. By these merits, CO in H2 stream can be reduced to < 1 × 10−6 with efficient photon utilization.