Constructing cascade electric fields and sulfur vacancies in Ni3S4/NiS2/v-Zn3In2S6 photocatalyst for efficient degradation of contaminants and H2 production

The flower-like Ni 3 S 4 /NiS 2 / v -Zn 3 In 2 S 6 with cascade electric fields and sulfur vacancies shows enhanced capability to produce H 2 and degrade bisphenol A (BPA) (or norfloxacin (NOR), tetracycline (TC)) simultaneously. • Growth of Ni 3 S 4 and NiS 2 on v -Zn 3 In 2 S 6 to construct cascade electric fields for fast charge dynamics and lowered over-potential for H 2 evolution. • Engineering S vacancies in the v -Zn 3 In 2 S 6 for metal-S dangling bonds to adsorb and activate the contaminants. • Cascade electric fields synergy with S vacancies in the Ni 3 S 4 /NiS 2 / v -Zn 3 In 2 S 6 for improved photocatalytic activity. The increasing environmental pollution and looming energy crisis necessitate the development of advanced photocatalysts that demonstrate efficient separation and transfer of the photo-generated holes and electrons, as well as multiple functions to address the above issues. Herein, a bifunctional Ni 3 S 4 /NiS 2/ v -Zn 3 In 2 S 6 photocatalyst has been constructed to degrade environmental hormones and antibiotics with simultaneous H 2 production. Sulfur vacancies have been engineered in the Zn 3 In 2 S 6 from a kinetic point of view to accelerate the separation of photogenerated charge carriers and act as active sites. Ni 3 S 4 and NiS 2 are introduced to construct cascade electric fields with Zn 3 In 2 S 6 via ohmic junctions for spatially separated charge carriers and reduced hydrogen evolution potential. As a result, the composite exhibits enhanced photocatalytic H 2 production and efficient degradation of bisphenol A, norfloxacin, and tetracycline, respectively. Specifically, the degradation pathways of BPA have been investigated based on Fukui calculations and liquid chromatography-mass spectrometry techniques. This work may shed new light on the design and construction of dual-function photocatalysts for wastewater treatment and H 2 production.