XAFS analysis for quantification of the gallium coordinations in Al2O3-supported Ga2O3 photocatalysts

16th International Conference on X-ray Absorption Fine Structure

Akatsuka, M.^1 ; Yoshida, T.^2 ; Yamamoto, N.^1 ; Yamamoto, M.^1 ; Ogawa, S.^1 ; Yagi, S.^2

Graduate School of Engineering, Nagoya University, Nagoya

464-8603, Japan^1

Eco Topia Science Institute, Nagoya University, Nagoya

464-8603, Japan^2

关键词: Arc tangent functions;    CO2 reduction;    Coordination structures;    Loading amount;    Photocatalytic activities;    Tetrahedral coordination;    XANES analysis;    XANES spectra;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/712/1/012056/pdf
DOI  :  10.1088/1742-6596/712/1/012056

来源: IOP

【 摘 要 】

Ga2O3loaded Al2O3samples (Ga2O3/Al2O3) were prepared to change coordination structures around Ga atoms. Ga K-edge XANES spectra of the Ga2O3/Al2O3samples showed two peaks assigned to Ga atoms having tetrahedral coordination structure (Ga(t)) and octahedral one (Ga(o)). Curve-fitting analysis of XANES spectra was carried out with a set of pseudo- Voight and arctangent functions, and the fractions of Ga(t) and Ga(o) were quantitatively estimated from the ratio of the peak areas. EXAFS curve-fitting analysis also evaluated the fractions of Ga(t) and Ga(o) and they were in good agreement with those obtained by XANES analysis. It was revealed that the fraction of Ga(t) increased with the decrease in the loading amount of Ga2O3due to the interaction of Ga species with Al2O3. The fractions of Ga(t) and Ga(o) might relate to the photocatalytic activity for CO2reduction with H2O over the Ga2O3/Al2O3samples.