| KIT-6负载CeO2催化CO2和甲醇合成碳酸二甲酯 |
| KIT-6 Supported CeO2 for Catalytic Synthesis of Dimethyl Carbonate from CO2 and Methanol |
| 作者 | 单位 | E-mail | | 史亚卜 | 太原理工大学, 煤科学与技术教育部和山西省重点实验室, 太原 030024 | | | 张国强 | 太原理工大学, 煤科学与技术教育部和山西省重点实验室, 太原 030024 | zgq198615@163.com | | 孙宇辰 | 太原理工大学, 煤科学与技术教育部和山西省重点实验室, 太原 030024 | | | 郑华艳 | 太原理工大学, 煤科学与技术教育部和山西省重点实验室, 太原 030024 | | | 李忠 | 太原理工大学, 煤科学与技术教育部和山西省重点实验室, 太原 030024 | lizhong@tyut.edu.cn | | 上官炬 | 太原理工大学, 煤科学与技术教育部和山西省重点实验室, 太原 030024 | | | 米杰 | 太原理工大学, 煤科学与技术教育部和山西省重点实验室, 太原 030024 | | | 刘守军 | 太原理工大学化学化工学院, 太原 030024 | | | 史鹏政 | 太原科瑞康洁净能源有限公司, 太原 030006 | |
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| 摘要: 采用不同老化温度（80、100、120和150℃）合成了一系列KIT-6载体，并通过浸渍法制备了相应的CeO2/KIT-6催化剂。结合X射线衍射、N2物理吸附、NH3程序升温脱附、CO2程序升温脱附、透射电子显微镜、傅里叶变换红外光谱和X射线光电子能谱等表征结果，详细考察了老化温度对KIT-6结构以及CeO2/KIT-6催化剂直接催化CO2和甲醇合成碳酸二甲酯（DMC）反应活性的影响。结果表明，不同老化温度下制备的KIT-6均保持其独特的三维孔道结构。随着老化温度升高，KIT-6比表面积先增大后减小，当老化温度为100℃时，KIT-6比表面积达到最大（683 m2·g-1）。KIT-6较高的比表面积有利于提高CeO2分散度，进而提高暴露的活性位点数量，催化活性随催化剂表面中等碱/酸性吸附位数量和Ce3+含量的增加而逐渐提高。其中，CeO2/100-KIT-6催化剂中CeO2颗粒尺寸最小（5.9 nm），暴露的活性位数量最高，催化活性最佳。随后，考察了反应温度和压力对CeO2/100-KIT-6催化活性的影响。随着反应温度提高，催化活性先升高后降低，当反应温度为140℃时，催化活性最高；且催化活性随反应压力的提高而逐渐增加。在反应温度为140℃、压力为6.8 MPa条件下，催化剂经6次循环后，DMC收率由15 mmol·gCeO2-1逐渐降低至2.8 mmol·gCeO2-1，原因归结为反应过程中CeO2纳米颗粒发生团聚，使暴露出的活性位数量减少。 |
| 关键词: CO2 CeO2/KIT-6 碳酸二甲酯 颗粒尺寸 活性位 |
| 基金项目: 山西省重点研发计划（国际科技合作项目）（No.201803D421011）资助。 |
| Abstract: A series of KIT-6 were synthesized by hydrothermal method at varied aging temperatures (80, 100, 120 and 150℃), which were used as supports to fabricate CeO2/KIT-6 catalysts. Combined with X-ray diffraction, N2-physisorption, temperature-programmed desorption of NH3 and CO2, transmission electron microscopy, Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy results, the effect of aging temperatures on the structure of KIT-6 and the catalytic activity of CeO2/KIT-6 for direct synthesis of dimethyl carbonate (DMC) from CO2 and methanol were investigated in detail. The results indicated that the KIT-6 synthesized at different aging temperatures maintained their unique three-dimensional pore structure. With the increasing aging temperature, the surface areas of KIT-6 firstly increased and then decreased, which attained the maximum (683 m2·g-1) as the aging temperature was 100℃. High surface areas of KIT-6 favor for the dispersion of CeO2 and thus improve the number of exposed active sites. The catalytic activity increases with the improved number of the medium base/acid adsorption sites and content of Ce3+. Herein, the particle size of CeO2 for CeO2/100-KIT-6 was the smallest (5.9 nm) and therefore the number of exposed active sites reached the maximum, which contributed to the optimal catalytic activity. Moreover, the effect of reaction temperature and pressure on the catalytic activity of CeO2/100-KIT-6 were studied. The results showed that the catalytic activity firstly increased and then decreased with the increasing reaction temperature, and attained the highest as the reaction temperature was 140℃. In addition, the catalytic activity increased with the increase of reaction pressure. Furthermore, the recycle stability of CeO2/100-KIT-6 was also studied under 140℃ and 6.8 MPa. The results showed that the DMC yield decreased from 15 mmol·gCeO2-1 to 2.8 mmol·gCeO2-1 after recycle six times, which is due to the decrease of active sites resulting from the agglomeration of CeO2 nanoparticles. |
| Keywords: CO2 CeO2/KIT-6 dimethyl carbonate particle size active sites |
| 投稿时间：2020-12-19 修订日期：2021-03-10 |
| 摘要点击次数: 1971 |
| 全文下载次数: 1121 |
| 史亚卜,张国强,孙宇辰,郑华艳,李忠,上官炬,米杰,刘守军,史鹏政.KIT-6负载CeO2催化CO2和甲醇合成碳酸二甲酯[J].无机化学学报,2021,37(6):1004-1016. |
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