Catalyst Preparation & Research
WANG Xiaolong, WANG Panpan, LI Yanpeng, LI Tong, ZHOU Yunyun, WU Ping, LI Nina
For improving the catalytic performance of Cu-based catalyst in CO2 hydrogenation to methanol,the conventional Cu/Zn/Al catalyst,HCT-Cu/Zn/Al catalyst with hydrotalcite as precursor and HCT-Cu/Zn/Al/Mg catalyst were prepared by co-precipitation method.The effects of hydrotalcite precursors and MgO additives on copper species dispersion,copper specific surface area,catalyst basic site,carbon dioxide hydrogenation activity and stability were investigated.Through SEM,N2O-TPD,H2-TPR,CO2-TPD and TEM characterization,it was found that the preparation of catalyst with hydrotalcite as the precursor system could promote the dispersion of copper species,increase the specific surface area of copper,and increase the strong alkaline sites of the catalyst surface.More importantly,the limiting effect of hydrotalcite could inhibit the sintering of copper species and improve the stability of the catalyst.In addition,MgO additive could further increase the specific surface area of copper,increase the strong alkaline sites on the catalyst surface,and inhibit the sintering of copper species.HCT-Cu/Zn/Al/Mg catalyst with hydrotalcite as precursor was used under the conditions of reaction temperature 250 ℃,reaction pressure 5 MPa,V(H2)∶V(CO2)=3∶1 and space velocity (GHSV)=10 000 mL·(g·h)-1.The methanol spatio-temporal yield was as high as 0.57 g·(g·h)-1,and methanol spatio-temporal yield was still 0.53 g·(g·h)-1 after reaction for 50 h,showing good stability.