Visible-light induced photo-degradation procedure of organic pollutants using a novel Z-scheme 0D/2D SnS2/MgO nano-heterojunction

Abstract

A Novel Z-scheme SnS₂/MgO nano-heterojunction was successfully synthesized by loading SnS₂ quantum dots on the surface of MgO nanosheets using a hydrothermal procedure. The morphology, surface features, chemical structure, and optical properties of the photocatalysts were characterized using various analyses. The FTIR, XRD, and EDS results confirmed the successful synthesis of the samples. The morphology of the MgO nanosheets was characterized using TEM, while photoluminescence results suggested a quantum dot structure for the SnS₂. DRS analysis revealed that the synthesized nano-heterojunctions exhibited an increased absorption intensity and a red-shift in the absorption edge within the visible-light region compared to SnS₂, suggesting the synergistic effects of SnS₂ and MgO. PL analysis indicated that all the nano-heterojunctions exhibited weaker photoluminescence than SnS₂, which suggests a delayed charge-carrier recombination and the enhanced photocatalytic performance. These findings were further corroborated by the results of PR and EIS. The photocatalytic performance of as-prepared photocatalysts was compared based on MB dye degradation. The results demonstrated that the optimized nano-heterojunction could completely remove MB within 120 min. Moreover, the effect of optimized nano-heterojunction dose and MB concentration on the photo-degradation rate was examined. The optimized nano-heterojunction exhibited good stability in five consecutive cycles of MB degradation. The trapping experiment of active species and DRS analysis revealed a Z-scheme pattern for charge-carrier transport between the two semiconductors.