Pt/WO3-TiO2/ZrO2-Al2O3甘油加氢体系中Al2O3的双功能催化作用研究

The bifunctional role of Al2O3 in Pt/WO3-TiO2 /ZrO2-Al2O3 catalyst for the improvement of hydrogenolysis of glycerol to 1,3-propanediol

摘要:

考察了WO3-TiO2/ZrO2-Al2O3四元氧化物中ZrO2:Al2O3质量比对Pt-WO3体系对质量分数30%甘油水溶液氢解制备1,3-丙二醇催化性能的影响，揭示了Al2O3组分在四元氧化物体系中的双功能作用。N2物理吸附脱附(BET)、X射线衍射(XRD)、傅里叶变换CO吸附及吡啶吸附红外光谱(FT-IR)、透射电镜(TEM)、程序升温还原(H2-TPR)等表征结果表明，氧化铝的掺入量直接影响到制备过程中WOx、ZrO2、TiO2等氧化物的晶相结构，进而影响到负载Pt纳米与载体的相互作用。在固定床反应器中，Pt-WO3-TiO2/ZrO2-Al2O3催化剂(Pt质量分数2%)上甘油转化率随着Al2O3质量比的升高逐渐降低，当ZrO2/Al2O3质量比为9:1时，催化活性最高，甘油转化率为38%，1,3-PDO选择性为49%，催化剂可稳定运行不低于100小时。

Abstract:

The influence of ZrO2/Al2O3 ratio on the catalytic performance of hydrogenolysis of glycerol over Pt supported on four-component oxides, namely WO3-TiO2-ZrO2-Al2O3 was systematically studied. The catalyst structure was characterized by several techniques such as BET, XRD, CO adsorption and pyridine adsorption FT-IR, and H2-TPR. The results suggested that introducing Al2O3 into the four-component oxides favors the dispersion of tetragonal phase ZrO2, on which highly dispersed Pt nanoparticles and monoclinic phase WO3 with strong metal-support interaction were formed. Thus formed structure benefits to the formation of Bronsted acid sites which improve the selectivity toward 1,3-propaneodiol. When ZrO2/Al2O3 was 9:1 in weight, the Pt/WO3-TiO2/ZrO2-Al2O3 catalyst showed 39% glycerol conversion and 1,3-PDO selectivity of 49% within 100 hours in a fixed-bed reactor.