草酸二甲酯加氢过程中Cu/SiO2催化剂失活机制研究OA

Hydrogenation of dimethyl oxalate to ethylene glycol is a representative technological pathway for the efficient and clean utilization of coal,which has garnered widespread attention under the background of"carbon neutrality".Although the route has been industrialized,current industrial setups still face the issue of catalyst deactivation.To investigate the mechanism of catalyst deactivation,Cu/SiO2 catalyst was selected as the model catalyst.Through stability evaluation tests,combined with characterization methods such as XRD,TEM,N2 adsorption/desorption,TGA and XPS,changes in the catalytic performances and structures of calcined,reduced and deactivated Cu/SiO2 catalysts were analyzed.The results indicate that the main causes of Cu/SiO2 catalyst deactivation are the agglomeration of Cu particles,carbon deposition,and changes of valence state of active component Cu.Among them,the agglomeration of Cu particles can reduce the numbers of active sites exposed on the catalyst surface,leading to a decline in catalytic activity.Carbon deposition,generated through a series of side reactions of intermediate products,can cover partial active sites on the catalyst,also resulting in decreasing of catalytic activity.Changes of valence state of Cu during the reaction can disrupt the synergistic effect between Cu+and Cu0 in the catalytic hydrogenation process,leading to catalyst deactivation.