What should people do with the huge amount of CO 2 captured? CO 2 to CO is a promising way for using carbon resources because CO is one component of syngas for the production of many important synthesis intermediates such as dimethyl oxalate (DMO). Hydrogenation of DMO provides an economical and eco-friendly approach for the synthesis of methyl glycolate, ethylene glycol (EG), and ethanol, which is often determined by the reaction conditions and catalysts with different active sites. Thus, DMO or EG is also an important carbon carrier or CO 2 utilization product. Also, DMO hydrogenation is a representative reaction for studying the structure−activity relationship in CO/C−O bond hydrogenation. Therefore, this work provides a comprehensive review of the progress in DMO hydrogenation from the perspective of constructing and stabilizing the active sites. The silver and copper based catalysts with different structures and morphologies used for DMO hydrogenation have been discussed with regard to their catalytic performance and reaction mechanism. The synergy of Cu 0 and Cu + in DMO hydrogenation has been questioned, and new active sites are proposed with more experimental evidence. New reaction routes, hybrid active sites, and the effect of catalyst structure on the active sites for DMO hydrogenation have been achieved and reviewed. Moreover, a strategy of introducing organic additives to improve EG yield and stabilize copper species has been described. This work may help advance the understanding of active sites in DMO hydrogenation and guide the future rational design and fabrication of highly stable and low-cost DMO hydrogenation catalysts.

No abstract

Fujian Institute of Research on the Structure of Matter, Chinese Academy of Sciences has achieved the industrialization of the first generation catalysts for coal to ethylene glycol for the first time in 2009. However, there are still lots of aspects to be improved, such as high noble metal loading and toxic Cr in catalyst of ester hydrogenation. To improve the catalysts, we have done systematic deep research about the nanostructures of catalysts, and revealed facet effect, size effect, synergistic effect, support effect, and so on. A series of catalysts preparation technologies have been developed to achieve the efficient utilization of noble metals. The Pd loadings of dehydrogenation catalyst and CO oxidative coupling catalyst have been dropped from 2.5% to 0.9% and 2.0% to 0.13%, respectively, while the catalytic performances are enhanced greatly. The toxic Cu-Cr in ester hydrogenation catalyst has been upgraded to green Cu-Si. The new catalysts for coal to ethylene glycol with advancement have been successfully developed with independent intellectual property rights.