title: Spatial Separation of Charge Carriers in In2O3-x(OH)y Nanocrystal Superstructures for Enhanced Gas-Phase Photocatalytic Activity.
abstract: The development of strategies for increasing the lifetime of photoexcited charge carriers in nanostructured metal oxide semiconductors is important for enhancing their photocatalytic activity. Intensive efforts have been made in tailoring the properties of the nanostructured photocatalysts through different ways, mainly including band-structure engineering, doping, catalyst-support interaction, and loading cocatalysts. In liquid-phase photocatalytic dye degradation and water splitting, it was recently found that nanocrystal superstructure based semiconductors exhibited improved spatial separation of photoexcited charge carriers and enhanced photocatalytic performance. Nevertheless, it remains unknown whether this strategy is applicable in gas-phase photocatalysis. Using porous indium oxide nanorods in catalyzing the reverse water-gas shift reaction as a model system, we demonstrate here that assembling semiconductor nanocrystals into superstructures can also promote gas-phase photocatalytic processes. Transient absorption studies prove that the improved activity is a result of prolonged photoexcited charge carrier lifetimes due to the charge transfer within the nanocrystal network comprising the nanorods. Our study reveals that the spatial charge separation within the nanocrystal networks could also benefit gas-phase photocatalysis and sheds light on the design principles of efficient nanocrystal superstructure based photocatalysts.
authors.affiliation: Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University , 199 Ren'ai Road, Suzhou, Jiangsu 215123, People's Republic of China.|Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Le
authors.initials: L
authors.lastname: He
authors.affiliation: Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Thomas E
authors.initials: TE
authors.lastname: Wood
authors.affiliation: Singapore-Berkeley Research Initiative for Sustainable Energy (SinBeRISE) , 1 Create Way, Singapore 138602.|Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 21 Nanyang Link, Singapore 637371.
authors.forename: Bo
authors.initials: B
authors.lastname: Wu
authors.affiliation: Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Yuchan
authors.initials: Y
authors.lastname: Dong
authors.affiliation: Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Laura B
authors.initials: LB
authors.lastname: Hoch
authors.affiliation: Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Laura M
authors.initials: LM
authors.lastname: Reyes
authors.affiliation: Institute of Nanotechnology and Karlsruhe Nano Micro Facility, Karlsruhe Institute of Technology , Hermann-von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
authors.forename: Di
authors.initials: D
authors.lastname: Wang
authors.affiliation: Institute of Nanotechnology and Karlsruhe Nano Micro Facility, Karlsruhe Institute of Technology , Hermann-von-Helmholtz Platz 1, 76344 Eggenstein-Leopoldshafen, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Kübel
authors.affiliation: Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Chenxi
authors.initials: C
authors.lastname: Qian
authors.affiliation: Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Jia
authors.initials: J
authors.lastname: Jia
authors.affiliation: Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Kristine
authors.initials: K
authors.lastname: Liao
authors.affiliation: Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Paul G
authors.initials: PG
authors.lastname: O'Brien
authors.affiliation: Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Amit
authors.initials: A
authors.lastname: Sandhel
authors.affiliation: Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Joel Y Y
authors.initials: JY
authors.lastname: Loh
authors.affiliation: Laser Dynamics Laboratory, School of Chemistry and Biochemistry, Georgia Institute of Technology , 901 Atlantic Drive NW, Atlanta, Georgia 30332, United States.
authors.forename: Paul
authors.initials: P
authors.lastname: Szymanski
authors.affiliation: Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Nazir P
authors.initials: NP
authors.lastname: Kherani
authors.affiliation: Division of Physics and Applied Physics, School of Physical and Mathematical Sciences, Nanyang Technological University , 21 Nanyang Link, Singapore 637371.
authors.forename: Tze Chien
authors.initials: TC
authors.lastname: Sum
authors.affiliation: Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Charles A
authors.initials: CA
authors.lastname: Mims
authors.affiliation: Materials Chemistry and Nanochemistry Research Group, Solar Fuels Cluster, Center for Inorganic and Polymeric Nanomaterials, Departments of Chemistry, Chemical Engineering and Applied Chemistry, and Electrical and Computing Engineering, University of Toronto , 80 St. George Street, Toronto, Ontario M5S 3H6, Canada.
authors.forename: Geoffrey A
authors.initials: GA
authors.lastname: Ozin
keywords: charge separation; gas phase; metal oxide semiconductor; nanocrystal superstructures; photocatalysis