β-AgAl1-xGaxO2 Solid-Solution Photocatalysts: Continuous Modulation of Electronic Structure toward High-Performance Visible-Light Photoactivity
- 10 March 2011
- journal article
- research article
- Published by American Chemical Society (ACS) in Journal of the American Chemical Society
- Vol. 133 (20), 7757-7763
- https://doi.org/10.1021/ja110691t
Abstract
A series of β-AgAl1-xGaxO2 solid-solution materials were explored as novel visible-light-sensitive photocatalysts. These Ag-based solid solutions crystallize in a homogeneous crystal structure with orthorhombic symmetry but possess continuously modulated band gaps from 2.19 to 2.83 eV by decreasing the ratios of Ga/Al. Their photoactivities for iso-propanol degradation were found to be dependent on the variation of chemical compositions. Among them, the β-AgAl0.6Ga0.4O2 sample showed the highest photocatalytic performance, which simultaneously exhibited 35 and 63 times higher activities than two terminus materials, β-AgAlO2 and β-AgGaO2, respectively. The apparent quantum efficiency of this sample for iso-propanol photodegradation achieved up to 37.3% at the wavelength of 425 ± 12 nm. The theoretical calculation based on density functional theory demonstrated that the levels of valence band maximum of β-AgAl1-xGaxO2 are similar, but the levels of conduction band minimum are gradually negatively shifted with the increase of the ratio of Ga/Al, thereby continuously narrowing the band gap. Nevertheless, the highest activity observed on β-AgAl0.6Ga0.4O2 may be attributed to its optimized band structure, which adapts the balance between effective visible-light absorption and adequate redox potentials.Keywords
This publication has 43 references indexed in Scilit:
- Effective decolorizations and mineralizations of organic dyes over a silver germanium oxide photocatalyst under indoor-illumination irradiationApplied Catalysis A: General, 2009
- New Series of Solid-Solution Semiconductors (AgNbO3)1−x(SrTiO3)x with Modulated Band Structure and Enhanced Visible-Light Photocatalytic ActivityThe Journal of Physical Chemistry C, 2009
- A Systematical Study on Photocatalytic Properties of AgMO2 (M = Al, Ga, In): Effects of Chemical Compositions, Crystal Structures, and Electronic StructuresThe Journal of Physical Chemistry C, 2009
- Heterogeneous photocatalyst materials for water splittingChemical Society Reviews, 2008
- Ag+- and Pb2+-Doped SrTiO3 Photocatalysts. A Correlation Between Band Structure and Photocatalytic ActivityThe Journal of Physical Chemistry C, 2007
- Photophysical and Photocatalytic Properties of Ca1-xBixVxMo1-xO4 Solid SolutionsThe Journal of Physical Chemistry B, 2006
- Daylight Photocatalysis by Carbon‐Modified Titanium DioxideAngewandte Chemie-International Edition, 2003
- Correlation of crystal and electronic structures with photophysical properties of water splitting photocatalysts InMO4 (M=V5+,Nb5+,Ta5+)Journal of Photochemistry and Photobiology A: Chemistry, 2002
- Visible-Light Photocatalysis in Nitrogen-Doped Titanium OxidesScience, 2001
- Photoemission study ofdelafossitesCo, Ni)Physical Review B, 2000