The aim of this work was to explore the influences of urea as a precipitant on the structural and catalytic performances of Zr–Sn–O catalysts for direct synthesis of DMC from CO₂ and CH₃OH. Zr–Sn–O catalysts were characterized by XRD, TEM, Raman spectroscopy, XPS, NH₃-TPD, CO₂-TPD, and N₂ adsorption. The results confirmed that urea used as a precipitant had a significant impact on the particle size, amount of oxygen vacancies, acid–base properties, BET surface area, pore structures and catalytic performances of the studied catalysts. The Zr–Sn–O-57.5 catalyst exhibited high catalytic activity with a DMC yield of 1.74 mmol g_cat⁻¹ and methanol conversion of 0.28%. Furthermore, the catalytic performance of Zr–Sn–O catalysts is directly related to the BET surface area. Thus, this work provides a new strategy for preparing catalysts for the direct synthesis of DMC.

中文翻译：

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尿素在调节 Zr-Sn 基氧化物催化剂结构性能中的作用，用于 CO2 和甲醇直接合成碳酸二甲酯

这项工作的目的是探索尿素作为沉淀剂对 Zr-Sn-O 催化剂的结构和催化性能的影响，该催化剂用于从 CO ₂和 CH ₃ OH 直接合成 DMC。通过XRD、TEM、拉曼光谱、XPS、NH ₃ -TPD、CO ₂ -TPD和N ₂吸附对Zr-Sn-O催化剂进行了表征。结果证实，用作沉淀剂的尿素对所研究催化剂的粒径、氧空位量、酸碱性质、BET表面积、孔结构和催化性能有显着影响。Zr-Sn-O-57.5 催化剂表现出高催化活性，DMC 产率为 1.74 mmol g _cat ^-1甲醇转化率为0.28%。此外，Zr-Sn-O 催化剂的催化性能与 BET 表面积直接相关。因此，这项工作为制备直接合成DMC的催化剂提供了新的策略。