Insights into performance and mechanism of improving methanol photoreforming on the ternary catalysts with p-n junction

Green hydrogen production from methanol is a pivotal technology for energy transformation. In this work, the heterojunction structure of NiO–TiO 2 and incorporated Pd/Ir/Ru nanoparticles were successfully prepared through the utilization of sol-gel and in situ photodeposition methods. The highest yield of hydrogen from methanol is contributed by 0.5Pd–1Ni–TiO 2 showing 80.73 mmol g −1 H 2 for 4 h, which is 15.03 times higher than the H 2 yield obtained using TiO 2 . Furthermore, this work reveals that methanol adsorbs in two states: molecular CH 3 OH and dissociated CH 3 O∗, and the main adsorption modes of methanol on the surfaces of TiO 2 , 1Ni–TiO 2 and 0.5Pd–1Ni–TiO 2 exhibit similarities, with bridge adsorption being identified as the most favorable mode. The possible mechanism of the formation of main products was proposed. HCOOH is formed by oxidation of HCHO, or from desorption of formate. The two C–C coupling reactions of ·COOH + ·COOH and ·COOH + ·CH 3 produce CH 3 COOH.