Youzhu Yuan-; ? orcid.org/; Email: yzyuan@xmu.edu.cn

Utilization of solar energy for photocatalytic H2 evolution coupled with value-added chemical synthesis is a promising avenue to address energy and environmental crises. Here, we report the hexamethylenetetramine (HMT) synthesis and H2 evolution from methanol and ammonia in one pot using a nanophotocatalyst of the conventional semiconductor TiO2 (P25) loaded with Pt (Pt/P25). The addition of ammonia inhibits byproduct ethylene glycol formation, promotes H2 evolution, and obtains HMT with high selectivity (>99.0%). The Pt valence state is regulated by calcination and reduction treatment, indicating that Pt/P25 is a stable catalyst for the photocatalytic synthesis of HMT from methanol and ammonia. The optimized formation rates of H2 and HMT are 71.53 and 11.39 mmol gcat-1 h-1, respectively. This work provides a green and sustainable pathway for the photocatalytic HMT synthesis coupled with H2 evolution under mild conditions.

Automated summary

Utilizing solar energy for photocatalytic H2 evolution coupled with value-added chemical synthesis is a promising solution for energy and environmental crises. In this study, a nanophotocatalyst of Pt/P25 was used to synthesize hexamethylenetetramine (HMT) and produce H2 from methanol and ammonia in one pot. The addition of ammonia inhibited the formation of byproduct ethylene glycol, promoted H2 evolution, and achieved high selectivity for HMT synthesis. The Pt valence state was controlled by calcination and reduction treatment, suggesting the stability of Pt/P25 as a catalyst. The optimized formation rates for H2 and HMT were 71.53 and 11.39 mmol gcat-1 h-1, respectively.