Photocatalytic CO2 reduction with water to produce value-added products is one of the promising solutions to mitigate CO2 emissions. TiO2 is most frequently studied photocatalysts in CO2 photoreduction as it is inexpensive, earth-abundant, and chemically stable. However, some darwbacks of using TiO2 include low light absorption in the visible range, low CO2 adsorption capability, and fast charge recombination. We have developed many strategies to improve the catalytic performance of TiO2 through surface engineering. One recent approach is to coat an ultrathin overlayer of metal oxide (e.g. Al2O3 or MgO) on TiO2 photocatalyst through atomic layer deposition (ALD). The ultrathin ALD layer has demonstrated significant benefit of lowering surface charge recombination. Another approach is to incorporate metal nanoparticles such as silver to promote electron-hole transfer and separation. Recently, we have integrated the two approaches by modifying a porous TiO2 photocatalyst with both an ALD coated MgO overlayer and Ag nanoparticles deposited on the surface. The experimental results have demonstrated significant synergy in CO2 photoreduction to CO and CH4 by incorporating the above two surface engineering approaches. We have also altered the sequence of the two surface modifications to investigate the structure-performance correlations.

New surface engineering strategy to promote photocatalytic CO2 reduction by TiO2 photocatalysts

2019 Spring National Meeting

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