Immunizing sulfate-mediated deactivation over TiO2 photocatalysts for gaseous benzene purification via self-adaptive deoxygenation of sulfate radicals

Abstract

Interactions between complex components in atmosphere have always engendered an elusive and uncontrollable pathway for gaseous contaminants purification among environmental catalysis. Herein, an intriguing phenomenon was noticed in which trace exposure of sulfate, one of the most ubiquitous environmental matrices in atmosphere, will induce rapid deactivation of the benchmark TiO2 photocatalysts for benzene purification. Fundamentally, the photogenerated sulfate radicals (•SO4-) would selectively oxidize benzene into benzoquinone but subsequently become the nucleus of benzoquinone polymerization, resulting from the fact that insufficient reactive oxygen species (ROS) cannot interrupt the excess deoxygenation of •SO4- in time. Whereby, the curvature of Ti-O steps was tactfully manipulated to spontaneously create a ROS-enriched environment, which maintained the balance of the catalytic reaction cycle by recovering the reacted •SO4- back and detaching the benzoquinone analogues to proceed sequential reactions. This work offers an ingenious strategy to develop efficient photocatalysts for practical applications.