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/S_V-ZIS) were fabricated for promoting photocatalytic water splitting (TAs and S_V-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/S_V-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.