Enhanced H2 Production Efficiency in Photo-Reforming of PET Waste Plastic Using Dark-Deposited Atom/Nanocomposite Pt/TiO2 Photocatalysts

Abstract

Photo-reforming waste polyethylene terephthalate (PET) in alkaline aqueous solutions is a novel approach for green hydrogen production. This study focuses on improving the catalytic efficiency of Pt/TiO2 for the photo-reforming of waste PET using an innovative dark deposition method to deposit Pt single atoms on nano TiO2 (Pt/TiO2), thereby increasing the catalytic efficiency while reducing the cost of the catalyst. The precursor concentration was optimized to control the size and distribution of the Pt clusters/atoms, and the TiO2 support was annealed at different temperatures to modify the properties of Pt/TiO2. Nine Pt/TiO2 catalysts were synthesized using different Pt precursor concentrations and annealing temperatures. The catalysts were characterized to measure their morphological, crystalline, and electronic properties, as well as their hydrogen yields via PET photo-reforming. The hydrogen conversion efficiency and external quantum yield (EQY) were calculated and compared with those of traditional direct-deposited catalysts. The correlation between the different characteristics of the dark-deposited and direct-deposited catalysts and their influence on the hydrogen yield in the photo-reforming process was statistically analyzed using principal component analysis. Catalysts deposited under dark conditions exhibited 5-fold and 7-fold enhancements in hydrogen conversion efficiency and EQY, respectively, compared to conventional catalytic systems. These findings indicate that the proposed catalytic system provides a viable solution for minimizing Pt loading, reducing the cost of the catalyst, and maintaining a higher hydrogen conversion efficiency.