Nickel Nanocluster Loaded Black Titania for Photocatalytic Reduction of CO2 into Solar Fuels: Computational and Experimental Studies

Tuesday, 3 October 2017
Prince George's Exhibit Hall D/E (Gaylord National Resort and Convention Center)
T. B. Reta (Inst.of Atomic and Molecular Sci,Academia Sinica, Nano Science and Technology Program,Academia Sinica), F. Y. Fu (Institute of Optoelectronic Science, NTOU, Center for Condensed Matter Sciences,NTU), P. Raghunath (Center for Interdisciplinary Molecular Science,NCTU), I. Shown (Inst. of Atomic and Molecular Sci., Academia Sinica), W. F. Chen (National Taiwan University), T. H. Shen (Inst. of Atomic and Molecular Sciences, Academia Sinica), M. C. Lin (Center for Interdisciplinary Molecular Science,NCTU), C. H. Lee (Dept of Engineering and System Science, NTHU), J. S. Hwang (Institute of Optoelectronic Science, NTOU), L. C. Chen (CCMS, National Taiwan University), and K. H. Chen (Inst. of Atomic and Molecular Sciences, Academia Sinica)
The conversion of atmospheric carbon dioxide (CO2) into solar fuels by imitation of a natural photosynthesis using only water vapor and sunlight for energy has attracted widespread attention recently. One of the key challenges is to design a photocatalyst that can bind and activate the CO2 molecule with smallest possible activation energy and produce selective solar fuel production. In this contribution, we report a combined experimental and computational studies on Ni nanocluster loaded black TiO2 (Ni@TiO2[Vo]) with built-in dual active sites for selective photocatalytic CO2 conversion. Our findings reveal that, the synergistic effect of deliberately induced unsaturated Ni nanocluster and oxygen vacancies provide (1) energetically stable CO2 binding sites with lowest activation energy (0.08eV), (2) highly reactive sites, (3) fast electron transfer pathway, (4) enhanced light harvesting by lowering the band gap. The Ni@TiO2[Vo] photocatalyst has demonstrated highly selective and enhanced photocatalytic activity of more than 18 times higher solar fuel production than the commercial TiO2 (P-25). An insight to the mechanism of interfacial charge transfer and product formation mechanism are explored. The proposed approach to adsorb and activate CO2 molecule on dual active sites can be applied to design other catalysts for photocatalytic CO2 reduction.