Photothermal Dry Reforming of Methane over Phyllosilicate-Derived Silica-Supported Nickel Catalysts

The development of catalytic technology for CO₂ recycling attracts much international attention for producing valuable chemicals and reducing CO₂ emissions. Photothermal dry reforming of methane (PT-DRM) is a promising technology to convert CO₂ into syngas (a mixture of CO and H₂) using solar energy. In this study, we found that silica-supported nickel catalysts (Ni/SiO₂) prepared via Ni phyllosilicate by the ammonia evaporation methods exhibited improved catalytic activity and enhanced resistance to sintering and carbon deposition in PT-DRM under visible and near-infrared light compared to that prepared by the conventional wetness impregnation method due to the highly dispersed Ni nanoparticles coated with thin SiO₂ layers. The catalytic activity and surface temperature reached maximums at the Ni loading of around 25 wt %. Furthermore, the light absorption and thermal diffusivity of the catalyst material increased with the increase in Ni loading, where the former contributes to the increase of the surface temperature and the latter to the decrease due to the higher heat dissipation. Hence, the Ni loading had positive and negative effects on the irradiated surface temperature of the catalytic part, and these thermal properties affected the photothermal catalytic activity for PT-DRM. These findings indicate the significance of suppressing heat dissipation in the design of photothermal catalysts for effective light energy utilization.