纳米LaFeO_3-TiO_2光催化还原CO_2

Photocataltic reduction of CO_2 by nanometer LaFeO_3-TiO_2

采用柠檬酸络合-溶胶-凝胶法制备LaFeO3-TiO2纳米催化剂,并用TG-DTA、FT-IR、UV-Vis、XRD对其表征,研究煅烧温度、LaFeO3复合量对光催化催化还原CO2制甲醇性能影响及反应优化条件。结果表明,LaFeO3与TiO2的复合可以抑制TiO2的晶相转变,拓宽催化剂光响应范围,提高光催化性能。优化条件为:催化剂煅烧温度为800℃,复合质量分数为3%的LaFeO3,催化剂用量为2.0g/L,反应时间为7h,CO2流量为200mL/min,反应温度为90℃,反应液中NaOH和Na2SO3的浓度均为0.10mol/L,甲醇的产率达325.49μmol/g。并初步探讨了LaFeO3-TiO2光催化还原CO2机理。

LaFeO3-TiO2 nanocatalyst was prepared by a citric-sol-gel method. The catalyst was characterized by TG- DTA, FTIR,UV--Vis and XRD technology. The effect of calcining temperature, LaFeO3 compounding quantity and reac- tion optimization conditions on the activity of photocatalytic reduction of CO2 to methanol were studied. It showed that in- corporation of LaFeO3 could effectively inhibit phase transformation from anatase phase to rutile and broaden the catalyst light-response range, thereby improving the photocatalytic performance. Catalyst was calcined at 800℃, the composite quali- ty score of LaFeO3 was 3 % , the amount of catalyst was 2.0g/L , the reaction time was 7h, CO2 flow 200mL/min, the reac- tion temperature was 90℃, the concentration of NaOH and Na2SO3 were 0. 10mol/L, yield of methanol reached 325. 49μmol/g. Mechanism of CO2 photocatalytic reduction on LaFeO3-TiO2 catalyst was proposed.