ZnZrOx integrated with chain-like nanocrystal HZSM-5 as efficient catalysts for aromatics synthesis from CO2 hydrogenation

Direct CO2 hydrogenation to high-value chemicals and fuels have received considerable attention. Nevertheless, efficiently producing aromatics with controllable aromatics distribution remains a great challenge. Herein, we report a series of bifunctional catalysts composed of highly active ZnZrOx oxides and nanocrystal HZSM-5 zeolites with the b-axis length ranging from 0.06 to 1.41 mu m, which enable direct CO2 hydrogenation into aromatics with high selectivity of 55-75 %. The CO2 conversion is up to 17.5 % with CO selectivity as low as 23.8 % mainly due to the affluent Brunsted acid sites and a large number of mesopores in HZSM-5 nanocrystal clusters with chain-like morphology. We demonstrate that a proper extension of the b-axis length of HZSM-5 can increase the selectivity of para-xylene (PX) while shortening the length of b-axis favors the formation of tetrame-thylbenzene (TeMB). The maximum selectivities of PX and TeMB in aromatics can reach to 28.9 % and 74.1 %, respectively.

Automated summary

In this study, a series of bifunctional catalysts composed of highly active ZnZrOx oxides and nanocrystal HZSM-5 zeolites were used to achieve direct CO2 hydrogenation into aromatics with high selectivity. The extension of the b-axis length of HZSM-5 was found to increase the selectivity of para-xylene (PX) while shortening the length favored the formation of tetramethylbenzene (TeMB), with maximum selectivities reaching 28.9% and 74.1%, respectively.