Cu改进CeO_(2)纳米棒表面氧空位和羟基官能团:催化CO_(2)和甲醇直接合成碳酸二甲酯  

Cu-modified CeO_(2)nanorods:enhanced surface oxygen vacancies and hydroxyl groups for direct synthesis of dimethyl carbonate from CO_(2)and methanol

作　　者：张迪 孙铭 丁靖 万辉 管国锋 ZHANG Di;SUN Ming;DING Jing;WAN Hui;GUAN Guofeng(College of Chemical Engineering,Nanjing Tech University,Nanjing 211800,China)

机构地区：[1]南京工业大学化工学院,江苏南京211800

出　　处：《南京工业大学学报(自然科学版)》2024年第6期613-624,共12页Journal of Nanjing Tech University(Natural Science Edition)

基　　金：国家自然科学基金(22278213)。

摘　　要：为了高效催化CO_(2)和甲醇直接合成碳酸二甲酯(DMC),采用水热法和沉积沉淀法相结合制备了Cu/CeO_(2)纳米棒催化剂。通过X线衍射(XRD)、透射电子显微镜(TEM)、H_(2)程序升温还原(H_(2)TPR)、CO_(2)程序升温脱附(CO_(2)TPD)、X线电子能谱(XPS)和热重分析(TGA)等表征手段对催化剂的结构和表面性质进行分析,研究了Cu的负载量和Cu/CeO_(2)焙烧温度对催化剂的表面性质和催化CO_(2)与甲醇直接合成DMC反应性能的影响。结果表明,当Cu的负载量(质量分数)为0.05%时,经过400℃焙烧后所得的Cu/CeO_(2)具有良好的催化CO_(2)和甲醇直接合成DMC效果。在反应温度150℃、CO_(2)压力为5 MPa和m(甲醇)/m(催化剂)为237.5时,DMC转化频率(TOF)达到9.0 mmol/(g·h),比纯CeO_(2)的DMC转化频率提升了38.6%。通过XPS、TG表征对催化剂表面氧空位和羟基进行半定量分析,研究发现,表面氧空位和羟基的协同作用增强了CO_(2)和甲醇的活化和共转化,进而提高催化性能。In order to efficiently catalyze the direct synthesis of dimethyl carbonate(DMC)from CO_(2)and methanol,Cu/CeO_(2)nanorod catalysts were prepared by using a combination of hydrothermal and deposition-precipitation methods.The structure and surface properties of the catalyst were analyzed by X-ray diffraction(XRD),transmission electron microscopy(TEM),H_(2)temperature-programmed reduction(H_(2)-TPR),CO_(2)temperature-programmed desorption(CO_(2)-TPD),X-ray photoelectron spectroscopy(XPS),and thermogravimetric analysis(TGA).The effects of Cu loading and calcination temperature of Cu/CeO_(2)on the surface properties and catalytic performance in the direct synthesis of DMC from CO_(2)and methanol were investigated.The results showed that with a Cu loading(mass percentage)of 0.05%and calcination at 400℃,the Cu/CeO_(2)catalyst exhibited excellent catalytic performance in the direct synthesis of DMC from CO_(2)and methanol.The turnover frequency(TOF)of DMC reached 9.0 mmol/(g·h)under reaction conditions of 150℃,CO_(2)pressure of 5 MPa and a methanol/catalyst mass ratio of 237.5,representing a 38.6%increase compared to pure CeO_(2).Semi-quantitative analysis of oxygen vacancies and hydroxyl groups on the catalyst surface by XPS and TG revealed that the synergistic effect of surface oxygen vacancies and hydroxyl groups enhanced the activation and co-conversion of CO_(2)and methanol,thereby improving the catalytic performance.

关 键 词：CO_(2) 碳酸二甲酯 CeO_(2) CU 焙烧温度 

分 类 号：TQ201[化学工程—有机化工]