Ni-Ir/SiO₂光热协同催化甲烷干重整探索

Photo-thermo catalysis can effectively reduce the reaction temperature of dry reforming of methane (DRM) and increase the reaction efficiency. The development of a new type of high-efficiency photo-thermo catalyst and the exploration of its catalytic mechanism are the focuses of current research. A self-confinement strategy was used to prepare nickel-iridium bimetallic catalyst (Ni-Ir/SiO₂). Catalyst physicochemical properties and photo-thermo catalytic performances on DRM were both studied. The results show that the bimetal nanoparticle has an average size of less than 3.5 nm and is evenly distributed on the substrate. The light absorption ability of the constructed ultra-small nickel-iridium bimetal is significantly enhanced. At the same time, the electrical field is also enhanced to effectively promote the hot electron excitation and realize its activation of methane and carbon dioxide molecules, especially their dissociation below the thermodynamic equilibrium temperature. In addition, the external heating of the system can further improve DRM reaction rate. Under the conditions of 700℃ and light intensity of 5 W/cm², the H₂ yield reaches 861 mmol/(g h), equivalent to that of the pure noble metal-based catalysts. Also, the catalyst shows good repeatability in the photo-thermo catalytic DRM reaction.