Boosted Solar Water Splitting over Direct S-Scheme Sulfur-Deficient ZnIn2S4/1D TiO2 Nanoarrays.

The construction of the S-scheme defect-engineered heterojunction (S-DEH) has been regarded as a rising promise to acquire operative carrier separation and electron transport in hybrid nanocatalysts, providing an inspired access to accomplish efficient solar-fuel production and realize eco-friendly energy evolution. Herein, visible-light-responsive sulfur-deficient ZnIn2S4 quantum dots/TiO2 nanoarrays (TAs/SV-ZIS) were fabricated for promoting photocatalytic water splitting (TAs and SV-ZIS stand for TiO2 nanoarrays and sulfur-vacancy ZnIn2S4 quantum dots, respectively). The experimental results indicated that the matched band gap, interfacial chemical bond introduced by defect engineering, and built-in electric field at the heterojunction interface drive the construction of the direct S-DEH system. Under simulated solar irradiation, the optimized hydrogen production rate of TAs/SV-ZIS is 72.475 mmol·h-1·g-1, which is ∼3.9 times than that for pristine TiO2 nanoarrays and ∼2.0 times than that for TAs/ZIS counterparts. The enhanced photocatalytic performance observed in TiO2 nanoarrays modified with ZnIn2S4 quantum dots referred to the improved charge transport, carrier separation efficiency, and extended electron lifetime because of the valid introduction of defect sites on the nanocomposites.