Zn0.2Zr0.8Ox固溶体催化剂的制备及其催化甲醇合成性能

Preparation of Zn0.2Zr0.8Ox Solid Solution and Catalytic Properties for Methanol Synthesis

以Zn(NO3)2·6H2O、Zr(NO3)4·5H2O为原料,Na2CO3为沉淀剂,采用并流共沉淀法制备了一系列不同Zn/Zr摩尔比的双金属氧化物催化剂,其结构经XRD、BET、Raman光谱、TEM和H2-TPR表征。结果表明:Zn0.2Zr0.8Ox催化剂为固溶体结构,比表面积最大达46.2 m^2·g^-1,还原性能良好。以催化CO2加氢合成甲醇为目标反应,对不同Zn/Zr摩尔比的催化剂进行性能测试,并考察了反应温度和反应时间对Zn0.2Zr0.8Ox催化剂性能的影响。结果表明:反应温度250℃、空速GHSV为12000 mL·g^-1h^-1、反应压力2 MPa和H2/CO2(体积比)=3/1时,Zn0.2Zr0.8Ox固溶体催化剂催化活性最高,二氧化碳转化率达到了3.5%、甲醇选择性高达75.4%,甲醇收率达到2.6%,且催化剂能够稳定运行100 h而不失活。

A series of catalysts with different Zn/Zr molar ratios were prepared by co-precipitation using Zn(NO3)2·6H2O and Zr(NO3)4·5H2O as raw materials and Na2CO3 as precipitant.The structures and properties of catalysts were characterized by XRD,BET,Raman spectra,TEM and H2-TPR.The results showed that Zn0.2Zr0.8Ox catalyst was a solid solution with a largest specific surface area of 46.2 m^2·g^-1 and better reduction performance.The performance of catalysts with different Zn/Zr molar ratios were investigated for CO2 hydrogenation to methanol,and the effect of different reaction temperature and reaction time on the performance of Zn0.2Zr0.8Ox solid solution catalyst also were considered,the results show that at the reaction temperature of 250℃,the GHSV of 12,000 mL·g^-1h^-1,reaction pressure of 2 MPa and H2/CO2=3/1(volume ratio),the Zn0.2Zr0.8Ox solid solution catalyst has the highest CO2 conversion rate and methanol selectivity,CO2 conversion of 3.5%,methanol selectivity of up to 75.4%,and methanol yield of 2.6%.Moreover,the catalyst can run for 100 h without inactivation.