Modulating the tunable interfacial charge transfer of Z-scheme TiO2/CdS with Ti–S bonds for enhanced glucose photoreforming

Abstract

Exploring and tuning the transport pathways of photo-generated carriers in biomass photoreforming is a highly attractive strategy for developing efficient and inexpensive catalysts for the production of hydrogen (H₂) and high-value chemicals. Here, (001)-facet-exposed TiO₂ and hierarchical marigold-like CdS composites (TiO₂/CdS) were fabricated to examine their glucose photoreforming activity toward H₂ and organic acid coproduction. The optimized 40%-TiO₂/CdS exhibited a high H₂ release rate (7.08 mmol g⁻¹ h⁻¹), which was about 3.93 and 354.00 times those of TiO₂ (0.02 mmol g⁻¹ h⁻¹) and CdS (1.8 mmol g⁻¹ h⁻¹), respectively. Furthermore, the glucose conversion and acetic acid selectivity of 40%-TiO₂/CdS were as high as 76.81% and 74.58%, respectively, after 4 h of photoreforming. The charge transfer pathways regulated by the Z-scheme heterojunctions with Ti–S bonds between TiO₂ and CdS significantly improve the glucose photoreforming activity, as demonstrated by the theoretical calculations, electron spin resonance (ESR), surface photovoltage (SPV), photoluminescence detection (PL) associated with the terephthalic acid (TPA) method, and X-ray photoelectron spectroscopy (XPS). This work provides a promising way for designing adjustable charge transfer pathways for effective photoreforming toward H₂ and acetic acid production.