Photocatalytic H{sub 2} production from spinels ZnGa{sub 2−x}Cr{sub x}O{sub 4} (0≤x≤2) solid solutions

Journal Article · Thu Oct 15 00:00:00 EDT 2015 · Journal of Solid State Chemistry

DOI:https://doi.org/10.1016/J.JSSC.2015.05.029· OSTI ID:22486793

Xu, Xiaoxiang ^[1]; Xie, Yinghao ^[1]; Ni, Shuang ^[2]; Azad, Abul K. ^[3]; Cao, Tongcheng ^[1]

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1. Shanghai Key Lab of Chemical Assessment and Sustainability, Department of Chemistry, Tongji University, 1239 Siping Road, Shanghai 200092 (China)
2. Science and Technology on Plasma Physics Laboratory, Laser Fusion Research Center, China Academy of Engineering Physics, Mianyang 621900 (China)
3. Faculty of Integrated Technologies, Universiti Brunei Darussalam, Jalan Tunku Link, Gadong BE1410 (Brunei Darussalam)

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.

• OSTI ID: 22486793
• Journal Information: Journal of Solid State Chemistry, Vol. 230; Other Information: Copyright (c) 2015 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0022-4596
• Country of Publication: United States
• Language: English

Related Subjects

37 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