Role of synthetically modulated polymers for efficient photoreforming hydrogen fuel

Abstract

Photoreforming biomass using TiO₂-based photocatalysts offers a sustainable approach to addressing environmental and energy challenges. This study introduces, for the first time, maltose-based polymers for photoreforming hydrogen generation studies, extending beyond the previously investigated glucose-based polymers. The findings are validated through both experimental and theoretical insights. The investigation explores how the structural complexity of disaccharides significantly influences the hydrophilicity of fluoro and non-fluoro polymers, as well as their effects on the photoreforming process. The structural properties of the synthesized polymers were characterized using various spectroscopic techniques, while their thermal properties were evaluated through TGA and DSC analysis. The glycopolymers with Pt/TiO₂ strongly influence the photoinduced charge separation and transfers; enabling enhanced H₂ production across a wide pH level. The fluoro-polymers with deacetylated maltose such as PPFBM-b-PMD and PPFPM-b-PMD synergistically increased the H₂ fuel production rate up to 1478 μmol g^-1h⁻¹ and 1363 μmol g^-1h⁻¹ compared to the non-fluoro glycopolymers. The improved hydrogen production may result from in-situ F doping of TiO₂ during the photoreforming process. Future studies will focus on optimizing conditions for large-scale biomass photoreforming, improving glycopolymer solubility, hydrophilicity, and electron-donating properties as substrates. First-principles based DFT calculations reveal that substituting F for surface O in Pt/TiO₂ creates conductive states near the conduction band, thereby enhancing electron mobility and photocatalytic performance, which aligns with the experimental findings.