Higher alcohol synthesis via syngas over CoMn catalysts derived from hydrotalcite-like precursors.

A series of CoMn catalysts derived from hydrotalcite precursors with different Co/Mn molar ratios were prepared and applied for higher alcohols synthesis (HAS) via syngas. The physical and chemical properties of as-prepared catalysts were investigated by various characterization methods such as BET, XRD, TPR, TG, SEM, HRTEM and EDS. The results showed that the proper Co/Mn molar ratio can increase the specific surface area, improve the reducibility, and form regular layered structure to provide more uniform distribution of active sites, thereby enhancing the catalytic activity and alcohol selectivity. When the Co/Mn ratio of catalyst reached 2, the highest space time yield (STY) and selectivity of alcohol were obtained. Moreover, the CoMn catalyst with layered structure showed higher activity and yield of alcohol under high reaction temperature than that without layered structure. Characterization results indicated that the layered structure catalyst can provide larger surface area, smaller particles size, and stronger interaction between Co and Mn, as well as resist the separation of Co, Mn and prevent the aggregation, thus improving the catalytic performance of CoMn catalysts for higher alcohols synthesis. In addition, the CoMn catalyst obtain derived from hydrotalcite precursors presented great stability for keeping active site highly disperse on the layer during the long reaction time. [ABSTRACT FROM AUTHOR]