Platinum nanoparticles (Pt NPs) are one of the most efficient cocatalysts in photocatalysis, and their size determines the activity and the selectivity of the catalytic reaction. Nevertheless, an in-depth understanding of the platinum’s size effect in the carbon dioxide photocatalytic reduction is still lacking. Through analyses of the geometric features and electronic properties with variable-sized Pt NPs, here we show a prominent size effect of Pt NPs in both the activity and selectivity of carbon dioxide photocatalytic reduction. Decreasing the size of Pt NPs promotes the charge transfer efficiency, and thus enhances both the carbon dioxide photocatalytic reduction and hydrogen evolution reaction (HER) activity, but leads to higher selectivity towards hydrogen over methane. Combining experimental results and theoretical calculations, in Pt NPs, the terrace sites are revealed as the active sites for methane generation; meanwhile, the low-coordinated sites are more favorable in the competing HER.

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The abuse of fossil fuels releases a large amount of CO2, causesing global warming intensified. Using photoreduction and electroreduction to convert CO2 into high valuable fuels like Co, CH4 and...

In this work, series bimetallic PtRu/TiO 2 (P1Rx/TiO 2 ) were prepared by one-pot glycol reduction method. The synergetic effect between Pt and Ru was discussed. Compared to mono-metal-decorated Pt/TiO 2 , P1Rx/TiO 2 showed enhanced electron separation ability due to the electron-withdraw ability of Ru. Also, enhanced photocatalytic CH 4 production was realized over P1R1/TiO 2 (yield rate of 7.82 μmol/g•h −1 and selectivity of 58.50%). Ru sites were proven to be effective CO 2 hydrogenation centers that could further convert byproduct H 2 into CH 4 during CO 2 photoreduction.