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<p>For CO<sub>2</sub> hydrogenation over iron-based catalysts, revealing the promoting effect of manganese and the nature of catalytically active sites remains a challenge that hinders targeted catalyst design. Here we elucidate the manganese-modulated restructuring of such catalysts during preconditioning and CO<sub>2</sub> hydrogenation using in situ X-ray absorption spectroscopy. The reaction-induced decoration of the surface of iron carbide with a MnO-containing layer is essential to hinder methane formation in favour of C<sub>2</sub>–C<sub>4</sub> olefins and C<sub>5+</sub> hydrocarbons. The selectivity changes were rationalized via spatially resolved steady-state and time-resolved (micro)kinetic tests combined with density functional theory calculations. The promoter affects the ability of iron carbide to generate surface species from H<sub>2</sub>, CO<sub>2</sub> and C<sub>2</sub>H<sub>4</sub>, thus controlling the surface C/H ratio, which is decisive for product selectivity. Consequently, the design of efficient multi-component heterogeneous catalysts requires a thorough understanding of the optimal catalyst architecture and, in particular, how to generate and stabilize it under reaction conditions.</p><p></p>

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Understanding Mn-modulated restructuring of Fe-based catalysts for controlling selectivity in CO2 hydrogenation to olefins

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2025年6月2日

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  • Qingxin Yang,
  • Elizaveta A. Fedorova,
  • Dong-Bo Cao,
  • Erisa Saraçi,
  • Vita A. Kondratenko,
  • Carsten R. Kreyenschulte,
  • Henrik Lund,
  • Stephan Bartling,
  • Jana Weiß,
  • Dmitry E. Doronkin,
  • Jan-Dierk Grunwaldt,
  • Angelika Brückner,
  • Haijun Jiao,
  • Evgenii V. Kondratenko

摘要

For CO2 hydrogenation over iron-based catalysts, revealing the promoting effect of manganese and the nature of catalytically active sites remains a challenge that hinders targeted catalyst design. Here we elucidate the manganese-modulated restructuring of such catalysts during preconditioning and CO2 hydrogenation using in situ X-ray absorption spectroscopy. The reaction-induced decoration of the surface of iron carbide with a MnO-containing layer is essential to hinder methane formation in favour of C2–C4 olefins and C5+ hydrocarbons. The selectivity changes were rationalized via spatially resolved steady-state and time-resolved (micro)kinetic tests combined with density functional theory calculations. The promoter affects the ability of iron carbide to generate surface species from H2, CO2 and C2H4, thus controlling the surface C/H ratio, which is decisive for product selectivity. Consequently, the design of efficient multi-component heterogeneous catalysts requires a thorough understanding of the optimal catalyst architecture and, in particular, how to generate and stabilize it under reaction conditions.