Unprecedentedly high efficiency for photocatalytic conversion of methane to methanol over Au-Pd/TiO - what is the role of each component in the system?

• Published in: Journal of materials chemistry. A, Materials for energy and sustainability Materials for energy and sustainability, 2021-05, Vol.9 (17), p.1796-182
• Main Authors: Cai, Xiaojiao, Fang, Siyuan, Hu, Yun Hang
• Format: Article
• ISSN: 2050-7488; 2050-7496
• DOI: 10.1039/d1ta00420d

Direct and highly efficient conversion of methane to methanol under mild conditions still remains a great challenge. Here, we report that Au-Pd/TiO 2 could directly catalyze the conversion of methane to methanol with an unprecedentedly high methanol yield of 12.6 mmol g cat −1 in a one-hour photocatalytic reaction in the presence of oxygen and water. Such an impressive efficiency is contributed by several factors, including the affinity between Au-Pd nanoparticles and intermediate species, the photothermal effect induced by visible light absorption of Au-Pd nanoparticles, the employment of O 2 as a mild oxidant, and the effective dissolution of methanol in water. More importantly, for the first time, thermo-photo catalysis is demonstrated by the distinct roles of light. Namely, UV light is absorbed by TiO 2 to excite charge carriers, while visible light is absorbed by Au-Pd nanoparticles to increase the temperature of the catalyst, which further enhances the driving force of corresponding redox reactions. These results not only provide a valuable guide for designing a photocatalytic system to realize highly efficient production of methanol, but also, highlight the great promise of thermo-photo catalysis. Direct and highly efficient methane conversion to methanol under mild conditions is achieved via photocatalysis over Au-Pd/TiO 2 .