Amorphous NiS-modified ZnIn2S4 nanosheets for highly efficient photocatalytic plastic reforming coupled with H2 evolution

Photocatalytic reforming of polylactic acid (PLA) plastic into green hydrogen (H 2 ) and high-value chemicals provides a promising approach for addressing environmental and energy issues. However, the rational design of high-performance photocatalysts remains a critical challenge. Herein, a novel NiS/ZnIn 2 S 4 (NS/ZIS) Schottky heterojunction is prepared through the uniform decoration of ZnIn 2 S 4 nanosheets with amorphous NiS. Mechanism studies reveal that the construction of Schottky barrier promotes the electrons transfer from ZnIn 2 S 4 to NiS, achieving efficient H 2 evolution. The photogenerated holes remaining on the surface of ZnIn 2 S 4 possess moderate oxidation activity, which can enable efficient and selective catalytic conversion of waste plastics to pyruvic acid (PA). Consequently, the NS/ZIS composite exhibits outstanding visible-light-driven generation rates of H 2 and PA, reaching 3.81 mmol g −1 h −1 and 2.95 mmol g −1 h −1 , respectively. These values are 4.6-fold and 2.3-fold as high as those acquired from pristine ZnIn 2 S 4 . It also achieves a PA selectivity of 80.6% and an apparent quantum yield of 10.3% at 420 nm. Moreover, the NS/ZIS thin film synthesized via drop-casting has prominent H 2 evolution activity and PA selectivity under natural sunlight exposure, which manifests its promising prospect in practical industrial utilization. This work presents a feasible method for converting waste plastic into H 2 and value-added chemicals, thereby contributing to the mitigation of escalating white pollution.