铁锆复合氧化物催化甲醇与CO2直接合成 DMC反应性能

采用溶胶-凝胶法制备的铁锆复合氧化物催化甲醇与CO2直接合成碳酸二甲酯（DMC）反应，其催化活性远高于氧化铁和氧化锆，当铁锆摩尔比为5：1时，其催化活性是氧化锆的2倍。利用XRD、XPS、IR、TPD和N2物理吸附-脱附等技术对催化剂进行了表征。结果表明，氧化铁主要以六方晶相的α-Fe2O3形式存在，氧化锆主要以四方晶相存在，铁锆之间发生了相互作用，使铁锆复合氧化物表面L酸增强和少量B酸产生。L酸的增强和B酸的产生是催化剂催化活性增加的主要原因，并对催化剂的催化作用机理进行了探讨。

Direct Synthesis of Dimethyl Carbonate from Methanol and Carbon Dioxide over Fe-Zr-O Catalyst

The Fe-Zr-O catalyst, prepared by sol-gel process, appears higher catalytic activity than Fe2O3 and ZrO2 alone in the direct synthesis of dimethyl carbonate (DMC) from methanol and carbon dioxide. The catalytic activity of the catalyst with iron zirconium molar ratio 5 is about two times higher than that of ZrO2. The working catalysts were characterized by IR, N2 adsorption/desorption, XRD, TPD-CO2(NH3), XPS. As a result, the ferric oxide mainly presents rhombohedral crystal and zirconia shows tetragonal crystal. There occurs interaction between iron and zirconium. The surface of Fe-Zr-O composite has Bronsted acid sites and stronger Lewis acid sites. Stronger Lewis acid and Bronsted acid increase the catalytic activity in the direct synthesis of dimethyl carbonate from methanol and carbon dioxide. The catalytic mechanism is presented in the paper.