A monolithic self-supporting ZnFe2O4/ZnO/ZnNi foam photocatalyst and application in the decomposition of gaseous benzene

[Display omitted] •A monolithic self-supporting ZnFe2O4/ZnO/ZnNi foam photocatalyst is prepared.•ZnNi foam affords the required Zn source for the formation of ZnFe2O4 and ZnO.•5ZFO/ZnO/ZNF shows the excellent removal and mineralization rate for benzene.•A monolith catalyst prepared in situ presents long-term reusability in VOC degradation reaction.•A Z-type heterojunction shows effective charge separation and high redox ability. Volatile organic compounds (VOCs) are major air pollutants which seriously affect ecological environment and pose threats to human health. In this investigation, a monolithic self-supporting ZnFe2O4/ZnO/ZNF(ZFO/ZnO/ZNF) photocatalyst was developed by in-situ growing ZnFe2O4 and ZnO on ZnNi foam (ZNF). Using benzene as a representative of the target gaseous contaminants, the optimal 5ZFO/ZnO/ZNF achieved a 99.8 % removal efficiency and 99.7 % mineralization efficiency within 20 min at an initial benzene concentration of 600 ppm under simulated sunlight irradiation. Moreover, this catalyst presents the lower ullage during gas–solid reaction, and thus enables durable recycling reuse of the photocatalyst, which still retains a 95.8 % benzene decomposition after 30th consecutive run. The mechanism studies reveal that the metal-mediated Z-type heterostructure of ZFO/ZnO/ZNF enhances rapid transportation of the photo-generated electrons and promotes redox potential, leading to the excellent photocatalytic oxidation activity and mineralization efficiency. This study highlights the potential of self-supporting monolithic metal-mediated catalysts and provides a key strategy for effective VOCs degradation.