Advancement of society has greatly relied on the consumption of fossil fuels, resulting in CO2 accumulation and the depletion of these non-renewable resources. A promising method to address both of these concerns simultaneously is converting CO2 into hydrocarbon products, for example, photosynthesis. Similar to the enzymes in plants, photocatalysts are required to reduce CO2 into valuable compounds. However, the conventional photocatalysts are TiO2 based materials that have high electron-hole recombination rates, decreasing the catalyst efficiency. To mitigate this issue, we utilized specially designed SnO2/graphene oxide particles as photocatalysts to convert CO2 and H2O into compounds including methane, formaldehyde, and methanol. Graphene oxide is a newly emerging material in photocatalysis. It has tunable bandgap (2.9 – 3.7 eV) and several types of oxygen containing functional groups, which can increase its performance in photoreduction of CO2. SnO2 has long been utilized to improve efficiency of Fe2O3, TiO2, and ZnO in photodegradation of dye molecules. It displays a bandgap of 3.8 eV. Our composite particles have a mean diameter of 500 nm with 3 nm-SnO2 colloids dispersed uniformly within them. Graphene oxide constitutes the frame of the composite particles. By our particle engineering, the band gaps and band positions of SnO2 and graphene oxide can decrease the recombination rate of electron-hole pairs, leading to an increased process efficiency. Our SnO2/graphene oxide particles exhibited high selectivity toward methane formation, more than 99 vol % of the products. The methane production rate is 5 times higher than that of commercially TiO2 (P25) under the same reaction conditions. The reaction paths were also investigated, to better understand the relationship between the particle structure and the photocatalytic performance.

Photoreduction of CO2 by SnO2/graphene oxide composite particles

254th National Meeting (2017)

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