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 electron-hole pair, resulting in great separation rate of charge carriers. The ESR results confirmed the existence of superoxide radical (•O2−), hole (h+) and hydroxyl radical (•OH) in the photocatalysis process. The •O2− 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. [Display omitted] •In2S3-MxInySz Z-scheme heterojunction photocatalysts with tube structure were synthesized.•Incorporation of Bi or La enhanced the redox ability of the nanoparticles through red-shift.•The heterostructure of the photocatalysts reduced the recombination of electron-hole pairs.•The material was treated by electron irradiation to produce donor defects and voids.•The photocatalysts possessed excellent properties for removal azo dyes and heavy metals.