Investigation of electron beam irradiation on In2S3-MxInySz (M = Bi or La) Z-scheme heterojunctions for efficient and stable degradation of water pollutants

Novel Z-scheme In2S3-MxInySz (M = Bi or La) heterojunction composites were fabricated through a hydrothermal method. An electron beam irradiation technology has been served for artificially creating interface defects on the composites to further enhance photocatalytic activity. SEM and TEM results showed that In2S3-MxInySz composites presented tubular structures composed of randomly assembled ultrathin nanosheets with the incorporation of Bi and La. XRD, FT-IR and XPS results proved that the as-synthesized heterostructure composites were mainly InBiS3 and InLa3S6. The In2S3-MxInySz composites presented distinct optical absorption property in visible lights region and exhibited highly enhanced photocatalytic efficiency for the removal of azo dyes and Cr(VI). Specifically, ISB-60 irradiated by electron beam displayed the best removal efficiency for the water pollutants. PL, DRS and EIS measurements showed that electron beam irradiation could reduce the recombination rate of photoexcited electronhole pair, resulting in great separation rate of charge carriers. The ESR results confirmed the existence of superoxide radical (center dot O2-), hole (h(+)) and hydroxyl radical (center dot OH) in the photocatalysis process. The center dot O-2(-) and h(+) species possessed a significant oxidizing effect towards the photodegradation of azo dyes and the photoreduction of Cr(VI). The possible transformation pathway for the removal of water pollutants by In2S3-MxInySz (M = Bi or La) composites was proposed by means of GC-MS. (C) 2019 Elsevier B.V. All rights reserved.