Phase Controllable Synthesis of Well-Crystallized Rhodium Sulfides by the Hydrothermal Method

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• 作者：Wuxing Zhang ; Kazumichi Yanagisawa ; Sumio Kamiya ; Tatsuo Shou
• 刊名：Crystal Growth & Design
• 出版年：2009
• 出版时间：August 5, 2009
• 年：2009
• 卷：9
• 期：8
• 页码：3765-3770
• 全文大小：388K
• 年卷期：v.9,no.8(August 5, 2009)
• ISSN：1528-7505

文摘

We developed a simple hydrothermal method to synthesize crystalline Rh₂S₃ and Rh₁₇S₁₅ at 400 °C for 5 h with a S/Rh molar ratio of 3 and 0.9, respectively. The formation mechanisms of the rhodium sulfides were proposed by decomposition of the CO ligand and sulfur incorporation during the hydrothermal reaction. The crystallization of the sulfides was closely related to the S/Rh ratio, reaction temperature, and reaction time. The formation of Rh₂S₃ requires abundant sulfur (S/Rh = 3), while Rh₁₇S₁₅ can be synthesized with a stoichiometric composition (S/Rh = 0.9). The thermal analysis shows that the low crystalline products obtained by hydrothermal reactions at 220 °C with S/Rh = 3 and 0.9 crystallize to Rh₂S₃ and Rh₁₇S₁₅ at 400 and 310 °C, respectively. However, calcination of Rh₂S₃ at high temperatures in Ar is accompanied by the release of sulfur, which finally results in the transformation of Rh₂S₃ into Rh₃S₄ and Rh₁₇S₁₅ at 700 °C.