K{sub 4}Nb{sub 6}O{sub 17}-derived photocatalysts for hydrogen evolution from water: Nanoscrolls versus nanosheets

Journal Article · Tue Jul 15 04:00:00 EDT 2008 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/j.jssc.2008.06.021· OSTI ID:21128359

Sarahan, Michael C ^[1]; Carroll, Elizabeth C; Allen, Mark; Larsen, Delmar S ^[1]; Browning, Nigel D ^[2]

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1. Chemistry Department, University of California, One Shields Avenue, Davis, CA 95616 (United States)
2. Chemistry and Materials Science Department, University of California, One Shields Avenue, Davis, CA 95616 (United States)

The layered hexaniobate K{sub 4}Nb{sub 6}O{sub 17} is known as a photocatalyst for methanol dehydrogenation and hydrogen evolution from water under ultraviolet (UV) light. Here we show that the activity is retained in propylammonium- (PA) or tetrabutylammonium- (TBA) stabilized H{sub 2}K{sub 2}Nb{sub 6}O{sub 17} nanosheets and TBA-stabilized H{sub 4}Nb{sub 6}O{sub 17} nanoscrolls that can be obtained by exfoliation of K{sub 4}Nb{sub 6}O{sub 17} followed by cation exchange. The catalytic activity of the exfoliated systems is comparable to K{sub 4}Nb{sub 6}O{sub 17}, with scrolls being most active in water, and PA sheets giving enhanced H{sub 2} rates due to sacrificial electron donor action of PA. Femtosecond absorption spectra for TBA scrolls and PA sheets exhibit broad features between 450 and 700 nm due to trapped holes and electrons. Electron-hole recombination follows approximately second-order kinetics, with rates of decay similar for sheets and scrolls. In addition, catalysts were characterized with UV/vis and fluorescence spectroscopy and transmission electron microscopy. - Graphical abstract: Nanosheets and nanoscrolls composed of individual niobate layers from K{sub 4}Nb{sub 6}O{sub 17} are active for hydrogen generation from water and aqueous methanol under UV irradiation.

• OSTI ID: 21128359
• Journal Information: Journal of Solid State Chemistry, Journal Name: Journal of Solid State Chemistry Journal Issue: 7 Vol. 181; ISSN 0022-4596; ISSN JSSCBI
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
ABSORPTION SPECTRA
BINDING ENERGY
DEHYDROGENATION
FLUORESCENCE SPECTROSCOPY
HOLES
HYDROGEN
INTERSTITIAL HYDROGEN GENERATION
ION EXCHANGE
KINETICS
LAYERS
METHANOL
NANOSTRUCTURES
NIOBATES
PHOTOCATALYSIS
POTASSIUM COMPOUNDS
SHEETS
TRANSMISSION ELECTRON MICROSCOPY
ULTRAVIOLET RADIATION
WATER