| 烧绿石结构Y2-xMgxRu2O7-δ(x=0.05、0.1、0.15)的制备及其OER催化活性 |
| Pyrochlore Structure Y2-xMgxRu2O7-δ (x=0.05, 0.1, 0.15): Preparation and OER Catalytic Performance |
| 作者 | 单位 | E-mail | | 韩天茹 | 桂林理工大学, 有色金属及材料加工新技术教育部重点实验室, 桂林 541004
桂林理工大学材料科学与工程学院, 桂林 541004 | | | 吴静静 | 桂林理工大学, 有色金属及材料加工新技术教育部重点实验室, 桂林 541004
桂林理工大学材料科学与工程学院, 桂林 541004 | | | 屈紫馨 | 桂林理工大学, 有色金属及材料加工新技术教育部重点实验室, 桂林 541004
桂林理工大学材料科学与工程学院, 桂林 541004 | | | 唐鑫 | 桂林理工大学, 有色金属及材料加工新技术教育部重点实验室, 桂林 541004
桂林理工大学材料科学与工程学院, 桂林 541004 | xtang@glut.edu.cn |
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| 摘要: 采用溶胶-凝胶法制备系列的镁掺杂Y2-xMgxRu2O7-δ（YMRO-x，x=0.05、0.1、0.15）催化剂，通过X射线光电子能谱对其进行价态分析发现，采用小离子半径的Mg2+取代烧绿石结构中处于A位的部分Y3+，进一步增加了烧绿石结构中氧缺陷数量，也引发了部分Ru4+转变为Ru5+，释放电子到表面，促进了氧析出反应（OER）。其中YMRO-0.1催化剂的含氧缺陷浓度最高，其催化活性最高。在达到10 mA·cm-2电流密度时，相比于RuO2（358 mV）、Y2Ru2O7-δ（294 mV），YMRO-0.1仅需施加265 mV过电位并且其Tafel斜率相对于RuO2（88 mV·dec-1）和Y2Ru2O7-δ（64 mV·dec-1）仅为45 mV·dec-1。此外，由于氧空位增多，即活性位点增多，降低了自由基从金属位点脱附的吉布斯自由能，促进了OER催化性能。第一性原理表明，替位原子MgY与氧空位形成复合体，可以降低氧空位形成能，同时随着Mg2+引入，带隙变小，电荷迁移能也随之变小，进而可以得到更高的催化活性。 |
| 关键词: 催化 电化学 第一性原理计算 溶胶-凝胶法 |
| 基金项目: 广西自然科学基金（No.2018GXNSFBA050013）资助。 |
| Abstract: Herein, pyrochlore structure Y2-xMgxRu2O7-δ (YMRO-x, x=0.05, 0.1, 0.15) catalysts were prepared by solgel method. The X-ray photoelectron spectroscopy was employed to analyze the surface chemical composition and valence state of as-synthesized YMRO. The results showed that oxygen defects were increased when Mg2+ partially substituted Y3+ of A site in pyrochlore (A2B2O7-δ). Especially, YMRO-0.1 catalyst possessed the most extraordinary performance in oxygen evolution reaction (OER). Reaching current density of 10 mA·cm-2 only required 265 mV overpotential, outperformed the RuO2 (358 mV), Y2Ru2O7-δ (294 mV), YMRO-0.05 (282 mV) and YMRO-0.15 (281 mV). The Tafel slope of YMRO-0.1 was 45 mV·dec-1, much smaller than that of RuO2 (88 mV·dec-1), YRO (64 mV·dec-1), YMRO-0.05 (51 mV·dec-1) and YMRO-0.15 (52 mV·dec-1), having the fastest kinetic process. Turning to stability test of YMRO-0.1, the potential moved little in 12 h, compared with Y2Ru2O7-δ which shifted up 30 mV under acidic environment. Moreover, first principle calculation indicated that the substitution atom MgY formed a complex with oxygen vacancies, favored the formation of oxygen vacancies, narrowed the band gap, and lowered the charge-transfer-energy. In addition, the excellent OER reactivity can be partly attributed to the Ru5+ ions. Due to the introduction of Mg, the Ru4+ ions at central active site was oxidized to Ru5+ ions, donating electron to surface and accelerating the process of oxygen evolution reaction. As a result, the active sites also minimized Gibbs free energy of oxygen radical desorption, which promoted the OER. Based on the results, YMRO should be a promising OER catalytic material which can stably work in acid environment. |
| Keywords: catalysis electrochemistry ab initio calculations sol-gel processes |
| 投稿时间：2020-08-30 修订日期：2020-12-09 |
| 摘要点击次数: 1971 |
| 全文下载次数: 1325 |
| 韩天茹,吴静静,屈紫馨,唐鑫.烧绿石结构Y2-xMgxRu2O7-δ(x=0.05、0.1、0.15)的制备及其OER催化活性[J].无机化学学报,2021,37(2):285-294. |
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