Thermocatalytic hydrogenation of CO2 into aromatics by tailor-made catalysts: Recent advancements and perspectives

Abstract

Considering the severe environmental issues brought by excessive carbon emissions, the utilization of CO2 as a feedstock for chemicals synthesis is gaining a lot of interest. CO2 hydrogenation into valuable chemicals using renewable energy is a promising strategy to alleviate the environmental pressures and reduce our strong dependence on fossil fuels simultaneously. Aromatics, as important chemicals in our daily life, can be synthesized by a tandem strategy that first converts CO2 into CO or methanol on Fe-based active sites or reducible metal oxides, respectively, and then sequentially conducts C-C coupling, dehydrogenation, and cyclization processes on acidic zeolites with unique topology structure for aromatics synthesis. This critical review focuses on the recent advancements in CO2 hydrogenation into high value-added aromatics (CTA), in particular the key factors, such as the catalytic component, the acidity distribution of the zeolite, and the proximity effect between different active sites that regulate the aromatics selectivity. The reaction network and mechanism during the tandem process will be discussed to guide the rational design of highly efficient bifunctional/multifunctional catalysts for direct synthesis of aromatics by CO2 hydrogenation. Furthermore, the development directions and obstacles of CO2 utilization by hydrogenation technology will be predicted to pave the way for the practical application of greenhouse gas CO2 for valuable aromatics synthesis. (Figure presented.).