纳米CeO_2的制备及液相合成碳酸二甲酯的研究

Preparation of nano-CeO_2 and its application to synthesis of Dimethyl carbonate by liquid phase catalysis

利用水热法控制水热温度和硝酸铈溶液的浓度制备了不同的纳米Ce O2颗粒,利用CO2-TPD技术和XRD表征分析了CO2和CH3OH在催化剂表面上的化学吸附和催化剂的粒径大小,并考察了其催化性能。研究结果表明,水热温度对制备纳米Ce O2催化剂的粒径大小影响显著,随着水热温度的升高,纳米Ce O2的粒径逐渐减小;随着硝酸铈浓度的增加,粒径先增加后减小。纳米二氧化铈的粒径大小对催化活性有显著的影响,且在100℃和150℃时的碱性位数量多少决定催化剂的催化性能,碱性位数量适中时催化效果较好。

Nano-Ce O2 was prepared by hydrothermal method at different hydrothermal temperatures and different concentration of cerous nitrate,CO2-TPD and XRD were used to analyze chemical adsorption of CO2 and CH3OH on the surface of catalyst and the particle size of catalyst,respectively,and the catalytic performance was studied. The results indicate that there is a significant effect of the hydrothermal temperature on particle size of nano-Ce O2,and particle size of nano-Ce O2 decreases gradually with the increase of hydrothermal temperature; and with the increase of concentration of cerous nitrate,the particle sizes increase firstly and then decrease. The particle size of nano-Ce O2 has a significant effect on catalytic performance,and the number of basic site of nano-Ce O2at100℃ and 150℃ decides catalytic performance of catalyst,and catalytic effect is better when the number of basic site is moderate.