Research Progress on CO2 Hydrogenation to Aromatics: Catalyst Design, Kinetic Modeling, and Reactor Engineering
Amid the global pursuit of carbon neutrality, the catalytic conversion of carbon dioxide (CO2) into high-value-added aromatics represents a critical frontier in sustainable chemistry. This process offers the dual benefit of mitigating greenhouse gas emissions while establishing a non-petroleum route for the production of indispensable platform chemicals. However, the practical realization of CO2 conversion is hindered by formidable challenges originating from the thermodynamic stability of CO2 and the kinetic challenges in C-C bond formation. This review provides a critical and comprehensive analysis of recent progress on CO2 hydrogenation to aromatics, focusing on the development of catalyst design, reaction kinetics, and reactor engineering, with the goal of accelerating industrial application. The two dominant reaction pathways, i.e., the methanol-intermediate and the olefin-intermediate routes, are summarized and progress in the design of efficient multifunctional catalysts for each pathway is given. A key point in bifunctional catalyst development is the challenge of balancing the synergy and separation of hydrogenation sites and acidic aromatization active sites. Synergy is crucial for driving the reaction equilibrium forward by rapidly consuming intermediates, whereas separation, often achieved through sophisticated architectures like core-shell structures, is vital for preventing deactivation, such as the migration of alkaline promoters into the zeolite (the aromatization component). Also, this review analyzes the kinetic modeling progress proposed for this complex, multi-step reaction system. For the initial CO2 conversion step, the authors highlighted the evolution of kinetic models, particularly the ongoing efforts to accurately quantify the critical water inhibition effect in methanol synthesis. For the subsequent aromatization stage, this review critically compares two distinct modeling strategies: the use of lumping models, which simplify the reaction network for robust engineering simulations, and the single-event microkinetic (SEMK) models, which offer profound mechanistic insights by considering elementary reaction steps. Furthermore, it is pointed out that these kinetic models serve as indispensable inputs for computational fluid dynamics (CFD) simulations, which guide the design, optimization, and scale-up of industrial reactors. These simulations can address practical engineering challenges such as thermal management to control hotspots and fluid dynamics to mitigate excessive pressure drop. By systematically bridging the conceptual gap from atomic-level catalyst design to macro-scale reactor optimization, this review provides theoretical guidance aimed at accelerating the engineering scale-up of this vital carbon utilization technology.