Stable Iron Nitride-Molybdenum Nitride/HZSM-5 Hybrid Catalysts for Direct CO2-to-Aromatics Conversion via Synergistic CO2-FTS Route

Objective

This project aims to develop a highly efficient and stable tandem catalytic system for the direct conversion of CO2 to benzene, toluene, and xylene (BTX). Current methanol-mediated routes suffer from low CO2 conversion and rapid deactivation due to temperature mismatch and catalyst instability. To address this, we propose a modified CO2-based Fischer-Tropsch synthesis (CO2-FTS) pathway using a bifunctional catalyst system: O2-passivated Fe2N/γ-Mo2N coupled with strategically modified HZSM-5 zeolite. The catalyst design employs a MoOₓ/γ-Mo2N support with abundant oxygen vacancies for efficient CO2 activation via reverse water-gas shift. Controlled O2 passivation creates interfacial Fe-O-Mo species that act as dynamic oxygen buffers, protecting the active Fe2N phase from oxidation and enhancing durability. The HZSM-5 component is engineered through dealumination and silanation to optimize acid site distribution and pore architecture, maximizing BTX selectivity while suppressing heavy aromatics and coke formation. Advanced characterization techniques, including modulation excitation spectroscopy (MES) coupled with operando XAS and DRIFTS, will be employed to resolve surface dynamics and reaction intermediates under working conditions. The project targets high performance metrics of >45% CO2 conversion and >80% BTX selectivity within the aromatic fraction. This multidisciplinary approach combining innovative catalyst design, sophisticated zeolite engineering, and cutting-edge operando diagnostics offers a sustainable and industrially relevant route for CO2 valorization into high-value chemicals.