π-π Stacked step-scheme PDI/g-C3N4/TiO2@Ti3C2 photocatalyst with enhanced visible photocatalytic degradation towards atrazine via peroxymonosulfate activation

[Display omitted] •A novel PDI/g-C3N4/TiO2@Ti3C2 (PCT) composite was synthesized successfully.•The π-π interaction in PCT can induce the electron delocalization effect.•The S-scheme heterojunction in PCT efficiently declined the electron recombination.•PCT presents enhanced degradation ability for atrazine via activating peroxymonosulfate.•The photocatalytic mechanism and degradation process of atrazine was studied. In this study, a novel π-π stacked PDI/g-C3N4/TiO2@Ti3C2 photocatalyst with step-scheme (S-scheme) heterojunction was constructed to boost the atrazine (ATZ) photocatalytic degradation by activating peroxymonosulfate (PMS). The π-π interaction in the PDI/g-C3N4 induced the delocalization of the photoelectrons, therefore promoted their migration. Meanwhile, the intimate contact and the staggered band configurations between the PDI/g-C3N4 and TiO2@Ti3C2 results in the S-scheme heterojunction thus declined the recombination of photocarriers. The π-π interaction and S-scheme heterojunction synergistically promoted the ATZ removal rate to 75% within one hour and can be well-adapted in a variety of environments. It was found that 1O2 domain the photocatalysis, and the H2O2 generated during the reaction may also be helpful for the process. The transformation of ATZ, intermediates, and three pathways during the process were also investigated via LC-MS. Moreover, the total organic carbon analysis shows that the mineralization of ATZ reached 46.08%.