The development of new ‘carbon utilization’ technologies from carbon dioxide (CO2) is necessary for the global decarbonization of our fossil fuel-based society and economy. However, current CO2-based chemical methodologies are still far from attaining their maximum functional potential due to the lack of in-depth mechanistic understanding. Therefore, the rational design of catalysts to develop chemical processes from CO2, through the fundamental understanding of reaction mechanisms (i.e., pieces of the puzzle), is of vital importance. To realize this ambition, we have developed an efficient one-pot catalytic process to convert CO2 directly to light olefins or aromatics (Figure 1) with high yields per pass. A unique combination of redox-acid bifunctional system (consisting an iron-based catalyst in combination with a highly acidic zeolite) has been employed, which exhibits analogous productivity from CO2 as Fisher-Tropsch processes based on synthesis gas. Herein, by employing a combination of advanced solid-state NMR spectroscopy (including proton-driven spin-diffusion using phase-alternated-recoupling-irradiation-schemes and hetero-nuclear correlation), UV-Raman spectroscopy as well as confocal fluorescence microscopy, we provide a detailed characterization of the reactive intermediates and the nature of the active catalyst material. This multi-spectroscopic approach also delicately distinguishes the reasonings behind the reactivity diffidence among two different classes of bifunctional catalytic systems (Figure 1). The acquired knowledge from this micro-spectroscopic approach will also be useful for the development of the few generations of superior and/or upgraded catalyst materials for the valorization of CO2.

Elucidation of reaction mechanisms of bifunctional metal oxide-zeolite catalyzed hydrogenation of carbon dioxide to hydrocarbons

2019 Spring National Meeting

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