The surface plasmon resonance effects of Ag NPs on photocatalytic performance of S-scheme SnSe/Ag-polyaniline heterojunction to degrade methylene blue dye and tetracycline antibiotic

The current research presents SnSe/Ag-polyaniline (Ag-PANI) heterojunction as S-scheme heterostructures with strong photocatalytic performance to degrade dye and antibiotic molecules under visible light irradiation. In the first step, the PANI composites have been functionalized by Ag NPs. Then, the SnSe/Ag-PANI heterojunction was produced by the co-precipitation method. In addition, the pristine SnSe NPs and SnSe/PANI heterojunction were also synthesized under similar conditions. Surface plasmon resonances (SPR) of Ag nanoparticles (NPs) on the photocatalytic performance of the SnSe/Ag-PANI heterojunction were investigated. The degradation time of more than 95 % of methylene blue (MB) dye was reduced from 60 min for the pristine SnSe NPS to 50 min for the SnSe/Ag-PANI heterojunction. In addition, the SnSe/Ag-PANI presented a higher photocatalytic performance than other samples to remove 99 % of the tetracycline (TC) antibiotic for 105 min. The X-ray diffraction (XRD) patterns of the products indicated that the PANI and Ag-PANI composites changed the growth direction of the SnSe, and a Se peak as an external peak was observed in the XRD patterns of the SnSe/Ag-PANI and SnSe/PANI heterojunctions. Bands and Fermi levels (Ef) alignment of the SnSe, Se, and PANI structures indicated a dual S-scheme heterostructure has been formed by SnSe/Se/PANI and SnSe/Se/Ag-PANI heterojunctions.