Ultrathin-Film Titania Photocatalyst on Nanocavity for CO2\n Reduction with Boosted Catalytic Efficiencies
Wang, Nam Sun
Mohammed, Omar F.
Ooi, Boon S.
KAUST DepartmentChemical Science Program
Computer, Electrical and Mathematical Sciences and Engineering (CEMSE) Division
Electrical Engineering Program
KAUST Solar Center (KSC)
Material Science and Engineering Program
Physical Science and Engineering (PSE) Division
Ultrafast Laser Spectroscopy and Four-dimensional Electron Imaging Research Group
Online Publication Date2018-09-19
Print Publication Date2018-11
Permanent link to this recordhttp://hdl.handle.net/10754/628796
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AbstractPhotocatalytic CO2 reduction with water to hydrocarbons represents a viable and sustainable process toward greenhouse gas reduction and fuel/chemical production. Development of more efficient catalysts is the key to mitigate the limits in photocatalytic processes. Here, a novel ultrathin-film photocatalytic light absorber (UFPLA) with TiO2 films to design efficient photocatalytic CO2 conversion processes is created. The UFPLA structure conquers the intrinsic trade-off between optical absorption and charge carrier extraction efficiency, that is, a solar absorber should be thick enough to absorb majority of the light allowable by its bandgap but thin enough to allow charge carrier extraction for reactions. The as-obtained structures significantly improve TiO2 photocatalytic activity and selectivity to oxygenated hydrocarbons than the benchmark photocatalyst (Aeroxide P25). Remarkably, UFPLAs with 2-nm-thick TiO2 films result in hydrocarbon formation rates of 0.967 mmol g−1 h−1, corresponding to 1145 times higher activity than Aeroxide P25. This observation is confirmed by femtosecond transient absorption spectroscopic experiments where longer charge carrier lifetimes are recorded for the thinner films. The current work demonstrates a powerful strategy to control light absorption and catalysis in CO2 conversion and, therefore, creates new and transformative ways of converting solar energy and greenhouse gas to alcohol fuels/chemicals.
CitationSong H, Wu W, Liang J-W, Maity P, Shu Y, et al. (2018) Ultrathin-Film Titania Photocatalyst on Nanocavity for CO2\n Reduction with Boosted Catalytic Efficiencies. Global Challenges: 1800032. Available: http://dx.doi.org/10.1002/gch2.201800032.
SponsorsH.S. and W.W. contributed equally to this work. This material is based upon work supported by, or in part by, the U.S. Army Research Laboratory and the U.S. Army Research Office under Contract/Grant No. W911NF-17-1-0363. This project was also partially supported by National Science Foundation (Grant Nos. CMMI1562057 and ECCS1507312).
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