Solar-driven CO2 hydrogenation can provide a renewable source of fuels and reduce greenhouse gas emissions at industrial scale. The paper investigates the light-driven Sabatier reaction over Ru films sputtered onto silica opal (Ru/SiO2) and inverted silicon opal photonic crystal (Ru/i-Si-o) supports. Under ambient temperature conditions, photomethanation rates over both the Ru/SiO2 and Ru/i-Si-o catalysts were shown to increase significantly with increasing light intensity, and rates as large as 2.8 mmol g−1 h−1 are achieved over the Ru/i-Si-o catalyst. Furthermore, the quantum efficiency of the photomethanation reaction was found to be almost three times larger when measured over the Ru/i-Si-o catalyst as compared to the Ru/SiO2 catalyst. DFT analysis indicate that charged Ru surfaces can destabilize adsorbed CO2 molecules and adsorb and dissociate H such that it can readily react with CO2, thereby accelerating the Sabatier reaction. See full paper at Energy & Environmental Science.
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