Na-α‿GeGaON Solid Solution Analogous to α‿SiAlON: Synthesis, Crystal Structure, and Potentiality as a Photocatalyst

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• 作者：Takayuki Suehiro ; Masataka Tansho ; Tadashi Shimizu
• 刊名：Inorganic Chemistry
• 出版年：2016
• 出版时间：March 7, 2016
• 年：2016
• 卷：55
• 期：5
• 页码：2355-2362
• 全文大小：516K
• ISSN：1520-510X

文摘

We demonstrated, for the first time, formation of the Na-α′-GeGaON (Na_mGe_12–(m+n)Ga_m+nO_nN_16–n) solid solution, an analogue of the well-established α′-SiAlON system. We successfully synthesized single-phase powder samples by reduction–nitridation of Na₂CO₃–GeO₂–Ga₂O₃, in the solubility range of m ≈ 0.8–1.7 with n ≈ 0.2–0.3. The Rietveld refinement of powder X-ray diffraction data for Na-α′-GeGaON was conducted on the basis of the space group P31c of α′-SiAlON, and the refinement converged with R_B = 1.78% and R_F = 1.02% for the composition of Na_1.26(1)Ge_10.50Ga_1.50O_0.24(1)N_15.76(1), indicating reliably the isomorphism between the SiAlON and GeGaON systems. The results of ²³Na solid-state nuclear magnetic resonance (NMR) spectroscopy clearly showed a single peak at the chemical shift of ∼16 ppm, further proving the accommodation of Na in the α′-GeGaON matrix with the expected coordination environment. The synthesized Na-α′-GeGaON exhibited stable photocatalytic activity for the evolution of H₂ from water under ultraviolet irradiation, which was comparable to that attained by β-Ge₃N₄.