Efficient Hybrid Photocatalysts For Carbon Dioxide Reduction Essay

1454 Words Oct 31st, 2016 6 Pages
Efficient hybrid photocatalysts for carbon dioxide reduction were developed from dye-sensitized TiO2 nanoparticles, and their catalytic performance was optimized by ternary organic/inorganic components. (E)-2-cyano-3-(5′-(5″-(p-(diphenylamino)phenyl)thiophen-2″-yl)thiophen-2′-yl)-acrylic acid and fac-[Re(4,4’-bis(diethoxyphosphorylmethyl)-2,2′-bipyridine)(CO)3Cl] were used as the sensitizer and the reduction catalyst (ReP), respectively, in the hybrid system, and both components were fixed onto TiO2 semiconductors (s-TiO2, h-TiO2, and d-TiO2). The Mott–Schottky analysis on flat-band potential (Efb) of TiO2 mesoporous films indicated that Efb can be finely modulated by varying the volume of water (0 to 20 vol%). The increase in added water substantially shifted Efb from ‒1.93 V at 0 vol% H2O to ‒1.74, ‒1.56, and ‒1.47 V at 3, 10, and 20 vol% H2O, respectively. As a result, with additon of 3‒10 vol% water in the photocatalytic reaction, conversion efficiency of CO2 to CO increased significantly reaching the TON value of ∼350 for 30 h. Catalytic activity enhancement is mainly attributed to 1) the optimum alignment of Efb by 3‒10 vol% water with respect to the Eox* of dye and Ered of ReP for smooth electron transfer from photo-excited dye to ReP via TiO2 semiconductor and 2) the water-induced acceleration of chemical processes on the fixed ReP. In addition, the energy level was further tuned by varying the dye and ReP amounts. The intrinsic properties such as morphology, size,…

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