Photothermal coupling-driven low-temperature steam reforming of acetic acid for hydrogen production

Low-temperature and high-efficiency acetic acid (AcOH) steam reforming was realized based on photo-thermal coupled catalysis. Four semiconductor materials (ZnO, TiO 2 , CeO 2 , CeO 2 -TiO 2 ) were used as the supports and Co was selected as the active metal. The physical phases, crystal structures and specific surface areas of the different catalysts were analyzed by various characterization methods. From the XPS spectra, it can be seen that CeO 2 loaded with TiO 2 to make a composite support produced a higher proportion of Ce 3+ ions and formed more oxygen vacancies on the catalyst surface. The catalytic activity of all four catalysts was low at temperatures less than 400 °C, and the carbon conversion and hydrogen yield gradually increased with increasing temperature. Co/CeO 2 -TiO 2 had the best catalytic activity among the four catalysts and the carbon conversion of Co/CeO 2 -TiO 2 could reach 97.9 % at 500 °C. When photothermal co-catalysis was introduced, the four catalysts activity was enhanced with different degree. The carbon conversion enhancements of Co/CeO 2 -TiO 2 photocatalytic reaction reached an impressive 714.9 % and 78.7 % at 300 and 350 °C respectively. The experimental results indicated that photo-thermal synergy had a more dramatic effect on the catalyst activity than single thermal drive at low temperatures. It might be due to the fact that the oxygen vacancies generated in the composite support CeO 2 -TiO 2 acted as electron supports to provide more favorable channels for the transport and migration of photogenerated electrons, which could effectively separate the photogenerated electrons and holes, thus improving the catalytic performance of the catalyst.