Bulk and interface regulation of ZnIn2S4/WS2 hybrids for boosting bi-functional catalysis: selective RhB photodegradation and electrocatalytic hydrogen evolution

ZnIn 2 S 4 /WS 2 hybrid exhibits selective RhB photooxidation and electrocatalytic HER. • pH = 2 ZnIn 2 S 4 could thoroughly photobleached RhB via complete mineralization. • S-scheme ZnIn 2 S 4 /WS 2 yielded Rh-110 intermediates via N-de-ethylation. • Strong interfacial interaction of heterojunction reduced ΔG H* and ΔG H2O* . RhB molecules could be selectively photodegraded over bare ZnIn 2 S 4 (advanced oxidation) and ZnIn 2 S 4 /WS 2 heterojunctions (Rh-110 intermediates via N-de-ethylation). Adequate band structure, interface electric field and S-scheme charge transfer pathway generated more • O 2 – radicals with strong reducibility. Thus, the best R  = 1:1 ZnIn 2 S 4 /WS 2 one showed ∼ 93.4% of removal efficiency toward RhB within ∼ 20 min of visible light irradiation, and RhB completely transformed into Rh-110 after 5 min of irradiation. Strong interfacial interaction between ZnIn 2 S 4 and WS 2 allowed R  = 1:1 ZnIn 2 S 4 /WS 2 electrode with the smallest Tafel slope of ∼ 78.06 mV dec -1 and charge transfer resistance in alkaline KOH electrolyte, which thus enhanced hydrogen evolution reaction (HER) activity and cycling durability of ZnIn 2 S 4 . The first-principle calculations demonstrated that the ZnIn 2 S 4 /WS 2 heterojunction exerts a desirable H* adsorption–desorption kinetic. ZnIn 2 S 4 /WS 2 heterojunction possesses superior dual functionality of selective photooxidation toward RhB and electrocatalytic hydrogen evolution, which is responsible for the S-scheme charge transfer and strong interfacial interaction. The first-principle calculations demonstrated its desirable H* adsorption–desorption kinetic. Download: Download high-res image (150KB) Download: Download full-size image