Figure 7 Reaction mechanism and pathways of the photocatalytic reduction of CO 2 with H 2 O vapor to fuels. Conclusions New nanoporous silica
(KIT-6 dried or calcined) incorporated with isolated Ti materials with different Si/Ti ratios (Si/Ti = 200, 100, and 50) synthesized has shown that Ti-KIT-6 (calcined, MI-503 order Si/Ti = 200, 100, and 50) were better in activity than the Ti-KIT-6 (dried, Si/Ti = 200, 100, and 50) materials, due to the presence of more accessible surface reaction Ti species. The main fuel products obtained after the reaction are CH4, CO, H2, and CH3OH (vapors). Moreover, it has been found that Ti-KIT-6 (Si/Ti = 100) shows a better product formation than Ti-KIT-6 (Si/Ti = 200 and 50). The high activity of the optimized photocatalyst was found to be due to the lower number of Ti-O-Ti or TiO2 agglomerates and to the more isolated Ti species, which were uniformly dispersed on the 3-D KIT-6 mesoporous silica support without damage to mesopore structure. The increased surface concentrations of OH groups found in Ti-KIT-6 also boosted the higher activity. It has been concluded
that the activity of the optimized Ti-KIT-6(Si/Ti = 100) is also much higher than that of the commercial Degussa P25 TiO2, due to the longer life and the more energetic active sites in the optimized Ti-KIT-6(Si/Ti = 100) photocatalyst than in the bulk commercial TiO2 one. These findings indicate that the highly dispersed isolated Ti, within the new KIT-6 mesoporous silica 3-D framework, can be considered a promising and effective photocatalyst CAL-101 purchase for CO2 conversion to fuels and as a suitable candidate for other research activities. Acknowledgements The financial support from the Eco2CO2 European Project (309701-2 Eco2CO2 CP-FP FP7-NMP-2012-SMALL-6) is gratefully acknowledged. References 1. Anpo M: Photocatalytic reduction of CO 2 with H 2 O on highly dispersed Ti-oxide catalysts as a model of artificial photosynthesis. J CO2 Utilization 2013, 1:8–17.CrossRef 2. Roy SC, Varghese OK, Paulose M, Grimes CA: Toward solar fuels:
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