Ruthenium Nanoparticles Supported on Mg(OH)₂ Microflowers as Catalysts for Photothermal Carbon Dioxide Hydrogenation

A strong sunlight-absorptive ability and high dispersity are considered as two key requirements of supported metal catalysts for efficient photothermal CO₂ conversions. The former can be improved by increasing the metal loading but often at the expense of decreasing the latter. Here we develop an ion-exchange route to supported Ru nanoparticles with both high loadings and dispersity that exhibit enhanced activity and relatively good stability in photothermal CO₂ catalysis. This strategy involves an ion-exchange reaction between Ru³⁺ and Mg­(OH)₂ to form uniformly distributed and chemically bonded Ru precursors on Mg­(OH)₂ supports. The subsequent low-temperature reduction by H₂ produces highly dispersed Ru nanoparticles whose sizes barely change as the loading increases. Our study provides an avenue for the preparation of strongly light-absorptive and highly dispersed metal catalysts for efficient conversion of carbon dioxide into solar fuels.