Extended Data Figure 10: Studies of temperature desorption and surface reactions.

a, Temperature-programmed surface reaction (TPSR) of methanol and water over 2%Pt/α-MoC. The very-low-temperature H₂ generation with CO₂ at 115 °C is due to the methanol reforming with water. The signals around 214 °C are attributed to the reaction of methanol and water adsorbed at bare α-MoC sites. b, TPSR of methanol and water over α-MoC. At low temperatures (166 °C), no C-containing species is generated, indicating that α-MoC cannot dissociate the C–H bond of methanol at this temperature, let alone catalyse the successive reforming or decomposition processes. In other words, Pt₁ is indispensable for low-temperature C–H clearage. Only at temperatures greater than 220 °C could α-MoC catalyse the methanol-reforming reaction. c, Temperature-programmed desorption (TPD) of methanol over 2%Pt/α-MoC. The signals at 145 °C are attributed to the intermolecular reforming of methanol, and the signals at 206 °C signals come from the decomposition of methanol into CO, CO₂ and H₂. d, TPSR of methanol and water over 2%Pt/Al₂O₃. Without α-MoC, Pt particles mainly catalyse methanol decomposition to CO and H₂, as the signals at 183 °C show. Owing to the lack of surface hydroxyl from water dissociation at this temperature, CO₂ does not form, and can be detected only at higher temperatures. The results show that the α-MoC support in the 2%Pt/α-MoC catalyst serves as the centre of water dissociation and suppresses the side reaction of methanol decomposition at low temperatures. The combination of Pt₁ and α-MoC renders this catalyst capable of water dissociation, C–H bond activation and reformation, and thus a good choice for low-temperature hydrogen production.