Faculty seminar "Toward industrializing CO2 hydrogenation to heavy hydrocarbons via novel and efficient tandem catalysts: Experimental and theoretical approaches" | Faculty of Chemistry at the Gdańsk University of Technology

Seminar 22^nd April 2026, 9:15, C.222 ChA

The Faculty of Chemistry at Gdańsk University of Technology cordially invites you to a seminar that will take place on April 22, 2026, at the Faculty of Chemistry, Gdańsk University of Technology, at 9:15 in room 222, Chemistry A Building.

Title: Toward industrializing CO₂ hydrogenation to heavy hydrocarbons via novel and efficient tandem catalysts: Experimental and theoretical approaches

Speaker: Prof. Samrand Saeidi, Department of Applied and Environmental Chemistry, Interdisciplinary Excellence Centre, University of Szeged, Rerrich Béla tér 1, Szeged 6720, Hungary; Email: samrand.saeidi@chem.u-szeged.hu

Abstract: The hydrogenation of CO₂ into valuable hydrocarbons represents a cornerstone strategy for sustainable energy and chemical production. Fe-based catalysts have emerged as promising candidates due to their high efficiency in the CO₂ hydrogenation toward C₂–C₄ olefins and C₅₊ hydrocarbons. Iron-based catalysts are particularly attractive due to their ability to drive both the reverse water–gas shift and Fischer–Tropsch reactions, yet their inherent phase complexity often hinders precise control over activity and selectivity. In this work, we present a rational tandem catalyst design wherein the key functional phases—Na‑promoted Fe3O4 (oxide) and phase‑pure Fe5C2 (carbide)—are synthesized separately and subsequently integrated. This decoupled approach enables systematic investigation of three critical parameters: the oxide/carbide mass ratio, the spatial proximity between the two phases, and the catalyst reduction pretreatment.

Our results demonstrate that an optimal oxide/carbide ratio (70 : 30 by weight) significantly enhances CO₂ conversion, attributed to synergistic effects that promote controlled reduction of the oxide phase and strengthen CO2 adsorption. Reducing the spatial distance between the two phases—by preparing mixed‑powder pellets—markedly improves selectivity toward C2–C4 olefins and C5+ hydrocarbons while suppressing methane formation, underscoring the importance of rapid intermediate (CO) transfer from oxide to carbide sites. Furthermore, reduction pretreatment induces the formation of graphitic carbon layers on the catalyst surface, which favor chain growth and lead to high selectivities (≈40 % for C2–C4 olefins and ≈35 % for C5+) at around 40 % CO2 conversion. In contrast, non‑reduced catalysts develop amorphous carbon that directs selectivity toward lighter paraffins and methane.

Based on these mechanistic insights, we propose a novel reactor configuration—a packed‑bed membrane reactor—to further increase CO2 conversion by in‑situ removal of water or hydrocarbon products, thereby shifting the thermodynamic equilibrium. The combination of a rationally designed tandem catalyst with advanced reactor engineering offers a promising pathway toward industrial‑scale CO2 hydrogenation, and ongoing theoretical efforts aim to unravel the molecular‑level interplay between catalyst phases and carbon morphology to guide future catalyst optimization.