Novel 2D/2D S-scheme Ni doped SnS2/BiOBr heterostructures with enhanced photocatalytic activity

Abstract

Herein, novel S-scheme heterojunction of Ni doped SnS2 (Ni-SnS2)/BiOBr (NSB) with 2D/2D structures was fabricated by a solvothermal-precipitation route, where 2D BiOBr nanoflakes were intimately deposited on the 2D Ni-SnS2 nanosheets surface. The obtained 2D/2D NSB composite presented largely boosted photocatalytic performances for tetracycline hydrochloride (TC) and dye decomposition compared to single catalyst. The optimized 20% Ni-SnS2/BiOBr (NSB-20) displayed the largest rate constant (0.0488 min−1), which was ca. 2.07 and 44.36 folds those of pure BiOBr and Ni-SnS2, respectively. In addition, it possessed good stability. The improved activity could be ascribed to excellent optical response, high contact areas and 2D/2D S-scheme heterostructures, which expedited efficiently separation and transfer of photocarriers. Furthermore, the effect of some factors on TC degradation was examined and possible degradation routes of TC were proposed. Finally, S-scheme charge transfer mechanism for NSB composite was put forward on the basis of band structure analysis, electron spin resonance (ESR), in situ XPS along with DFT calculations. This investigation contributes to exploit S‐scheme 2D/2D materials for environmental remediation.