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Photocatalytic CO 2 Reduction using a Molecular Cobalt Complex Deposited onto TiO 2 Nanoparticles Tong Jin, Chao Liu, and Gonghu Li * Department of Chemistry, University of New Hampshire, Durham, NH 03824. Motivation. Experimental Results. Results (continued).
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Photocatalytic CO2 Reduction using a Molecular Cobalt Complex Deposited onto TiO2 Nanoparticles Tong Jin, Chao Liu, and GonghuLi * Department of Chemistry, University of New Hampshire, Durham, NH 03824 Motivation Experimental Results Results (continued) • Carbon dioxide is a renewable C1 feedstock for the production of chemicals, materials, and fuels; • Integrating molecular catalysts with nano-structured surfaces could improve stability, enhance reactivity and provide novel reaction pathways; • It remains a challenge to effectively couple catalysts with energy sources (photosensitizers). • Deposition on TiO2 Surfaces • Photocatalysis: in situ FTIR Spectroscopy • Effect of Synthetic Method • Importance of Surface Ti-OH Groups Table 1 TONs of CO after CO2 reduction for 4 h using hybrid photocatalysts and TEOA as the sole electron donor. CO CO2 Conditions: TEOA/MeOH UV light + • CoIII(cyclam)X/TiO2 prepared by the microwave method shows better activity in CO2 reduction. Background Fig. 1 CO production in photocatalytic CO2 reduction using (a) TiO2 +[Co(cyclam)Cl2]Cl, (b) CoIII(cyclam)X/TiO2. e- hv Ti-OH • Photoexcitedelectrons in TiO2 conduction band can be transferred to CoIII(cyclam)X on surface for CO2reduction. CoIII(cyclam)X/P25 D CO h+ e- hv D+ CO2 CoIII(cyclam)X/Anatase e- hv h+ CoIII(cyclam)X/Rutile D h+ Bare TiO2 Co cyclam TiO2 D+ CO-Co3+ J. Am. Chem. Soc. 1995,117, 6708 CO-Co2+ • TiO2 as UV Light Photosensitizer • Our approach: couple Co cyclam with TiO2 nanoparticles for CO2 reduction. • The presence of hydroxyl groups is important for the deposition of CoIII(cyclam)X on TiO2 surface. Chem. Commun., 2014, 50, 6221 e- hv TiO2 as a UV photosensitizer Fig. 2Difference DRIFTS spectra of (a) TiO2after UV irradiation for 150 min, and (b) CoIII(cyclam)X/TiO2 after UV irradiation for 10, 30, 60 and 150 min (from bottom to up). Conclusion h+ • A hybrid photocatalystCoIII(cyclam)X/TiO2 was prepared for CO2 reduction; • Current work focuses on studying electron transfer across the Co/TiO2 catalyst interface using electron paramagnetic resonance spectroscopy. • CoIII(cyclam)X is the active CO2-reduction catalyst in CoIII(cyclam)X/TiO2. Ind. Eng. Chem.Res.2012, 51, 11841 Chem. Commun., 2014, 50, 6221 NSF CAREER Award # CHE-1352437