Revealing the Efficient and Constant Photon Utilization of Photocatalytic Fixed Bed Reaction.

Because of the very high potential barrier, semiconductor-co-catalyst interfacial electron transfer occurring on a second time scale severely slows the photocatalytic reaction. Besides, the undesired deprivation of electrons from the co-catalyst by photogenerated oxidative intermediates in a photocatalytic slurry suspension further lowers the light-intensity-dependent photon utilization. We demonstrate here that photocatalyst immobilization can flatten the potential barrier and increase the selectivity of electrons for the target reaction. This is because the induced spatial separation of half reactions in the formed fixed bed reactors can suppress the loss of photogenerated charge carriers and increase the density of electrons in the semiconductor. The photocatalytic fixed bed reaction thus exhibits efficient and constant photon utilization.