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<p>Ethanol steam reforming (ESR) offers a sustainable route for hydrogen production, yet its complex reaction network and elusive intermediates hinder catalyst optimization. Here, we identify the vinyloxy radical (CH<sub>2</sub>CHO) as the critical chain-carrying intermediate in ESR over Ni/La<sub>2</sub>O<sub>3</sub> catalysts, challenging the conventional view of acetyl radical (CH<sub>3</sub>CO) dominance. Through in situ synchrotron vacuum ultraviolet photoionization mass spectrometry with molecular beam sampling (SVUV-PI-MBMS), combined with density functional theory (DFT) calculations and microkinetic modeling, the dynamic speciation of gas-phase radicals and stable products are resolved across 473–1073 K. Experimental results reveal CH<sub>2</sub>CHO as the predominant intermediate, absent CH<sub>3</sub>CO detection. DFT calculations provide a theoretical foundation that supports the experimental observations, demonstrating that the CH<sub>2</sub>CHO-mediated pathway has a kinetic advantage over the CH<sub>3</sub>CO pathway. This finding aligns with kinetic simulation results, which reveal that CH<sub>2</sub>CHO controls 75% of the formaldehyde conversion flux. This work redefines the ESR mechanistic framework, offering a strategy to tailor catalytic pathways via intermediate control.</p>

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Vinyloxy radicals unveiled as critical intermediates in Ni/La2O3-catalyzed ethanol steam reforming for hydrogen production

  • 期刊论文

  • 出版模式：

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  • 发表日期：

    2025年12月7日

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  • Zaili Xiong,
  • Xiaokuan Ban,
  • Wenhao Yuan,
  • Meirong Zeng,
  • Yuwen Deng,
  • Jijun Guo,
  • Yang Ma,
  • Jiuzhong Yang,
  • Long Zhao,
  • Chusheng Chen,
  • Fei Qi

摘要

Ethanol steam reforming (ESR) offers a sustainable route for hydrogen production, yet its complex reaction network and elusive intermediates hinder catalyst optimization. Here, we identify the vinyloxy radical (CH2CHO) as the critical chain-carrying intermediate in ESR over Ni/La2O3 catalysts, challenging the conventional view of acetyl radical (CH3CO) dominance. Through in situ synchrotron vacuum ultraviolet photoionization mass spectrometry with molecular beam sampling (SVUV-PI-MBMS), combined with density functional theory (DFT) calculations and microkinetic modeling, the dynamic speciation of gas-phase radicals and stable products are resolved across 473–1073 K. Experimental results reveal CH2CHO as the predominant intermediate, absent CH3CO detection. DFT calculations provide a theoretical foundation that supports the experimental observations, demonstrating that the CH2CHO-mediated pathway has a kinetic advantage over the CH3CO pathway. This finding aligns with kinetic simulation results, which reveal that CH2CHO controls 75% of the formaldehyde conversion flux. This work redefines the ESR mechanistic framework, offering a strategy to tailor catalytic pathways via intermediate control.