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Author Xu, Xiaoxiang ♦ Xie, Yinghao ♦ Ni, Shuang ♦ Azad, Abul K. ♦ Cao, Tongcheng
Source United States Department of Energy Office of Scientific and Technical Information
Content type Text
Language English
Subject Keyword INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY ♦ ABSORPTION ♦ CHROMATES ♦ COMPARATIVE EVALUATIONS ♦ CRYSTAL STRUCTURE ♦ DENSITY OF STATES ♦ ELECTRONIC STRUCTURE ♦ GALLIUM OXIDES ♦ HYDROGEN PRODUCTION ♦ OPTICAL PROPERTIES ♦ PHOTOCATALYSIS ♦ SOLID SOLUTIONS ♦ SOLIDS ♦ SPIN ORIENTATION ♦ SPINELS ♦ SURFACES ♦ VALENCE ♦ VISIBLE RADIATION ♦ ZINC COMPOUNDS
Abstract Solid solutions of ZnGa{sub 2−x}Cr{sub x}O{sub 4} (0≤x≤2) were successfully prepared by solid state reactions. Introducing Cr into ZnGa{sub 2}O{sub 4} crystal structure significantly improves its light absorption and greatly enhances its photocatalytic activity. An optimized Cr content (x=1.5 for ZnGa{sub 0.5}Cr{sub 1.5}O{sub 4}) was found for the solid solutions with the highest photocatalytic hydrogen production rate (~775 μmol/h). Compositional analysis suggests there is a strong enrichment of Cr at the surface of sample ZnGa{sub 0.5}Cr{sub 1.5}O{sub 4} compared with other samples. Theoretical calculations suggest their electronic structures involve spin-polarized conduction band (CB) and valence band (VB) that are mainly composed of Cr 3d orbitals. The highest photocatalytic activity observed in ZnGa{sub 0.5}Cr{sub 1.5}O{sub 4} is probably due to the higher Cr content at the surface that favors the Cr 3d orbital overlapping. - Graphical abstract: Electronic structure and density of states of ZnGa{sub 2}O{sub 4} after partially substituting Ga with Cr. - Highlights: • Complete solid solution can be formed between ZnGa{sub 2}O{sub 4} and ZnCr{sub 2}O{sub 4}. • Optical properties and catalytic activity are improved by adding Cr into ZnGa{sub 2}O{sub 4}. • An optimized Cr content exists for the highest activity. • Enrichment of Cr in the surface is beneficial for a better performance.
ISSN 00224596
Educational Use Research
Learning Resource Type Article
Publisher Date 2015-10-15
Publisher Place United States
Journal Journal of Solid State Chemistry
Volume Number 230


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