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<p>Ammonia is a promising hydrogen carrier for a carbon-neutral energy economy, but its widespread application hinges on the development of highly efficient catalysts for low-temperature decomposition. Overcoming the high activation barriers for N–H bond cleavage, particularly for non-precious metal catalysts like cobalt, remains a formidable challenge. Herein, we report the design and synthesis of a novel Co catalyst supported on a Ce and N co-modified perovskite (Co@La<sub><i>x</i></sub>Ce<sub>1−<i>x</i></sub>AlO<sub>3−<i>y</i></sub>N<sub><i>z</i></sub>). The optimized Co@La<sub><i>x</i></sub>Ce<sub>1−<i>x</i></sub>AlO<sub>3−<i>y</i></sub>N<sub><i>z</i></sub> catalyst demonstrates exceptional performance, achieving 92.6% ammonia conversion with a hydrogen production rate of 9.7 mmol g<sup>−1</sup> min<sup>−1</sup> at a remarkably low temperature of 425 °C (gas hourly space velocity (GHSV) = 9000 mL h<sup>−1</sup> g<sub>cat</sub><sup>−1</sup>). This represents a 125 °C reduction in operating temperature compared to conventional Co-based catalysts under similar conditions. Mechanistic investigations using isotopic labeling and <i>in-situ</i> diffuse reflectance infrared Fourier transform spectroscopy reveal that the synergistic modification of Ce and N creates a unique LA-L(A+B)-LB active site configuration. This structure significantly lowers the Schottky barrier at the metal-support interface, promoting facile hydrogen spillover. Crucially, the reaction proceeds via an interfacial Mars-van Krevelen mechanism, a stark contrast to the traditional Langmuir-Hinshelwood pathway on conventional Co catalysts. This study provides new insights for developing low-temperature Co-based catalysts for ammonia decomposition.</p>

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Enhanced hydrogen spillover effect in low-temperature ammonia decomposition via N-coordination and O-vacancy-activated Co/LaxCe1−xAlO3−yNz catalyst

  • 期刊论文

  • 发表日期：

    2025年12月4日

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  • Cheng Zuo,
  • Qian Su,
  • Jing Wang,
  • Hui Zhao,
  • Min Wang,
  • Xishi Tai,
  • Xiangke Wang

摘要

Ammonia is a promising hydrogen carrier for a carbon-neutral energy economy, but its widespread application hinges on the development of highly efficient catalysts for low-temperature decomposition. Overcoming the high activation barriers for N–H bond cleavage, particularly for non-precious metal catalysts like cobalt, remains a formidable challenge. Herein, we report the design and synthesis of a novel Co catalyst supported on a Ce and N co-modified perovskite (Co@LaxCe1−xAlO3−yNz). The optimized Co@LaxCe1−xAlO3−yNz catalyst demonstrates exceptional performance, achieving 92.6% ammonia conversion with a hydrogen production rate of 9.7 mmol g−1 min−1 at a remarkably low temperature of 425 °C (gas hourly space velocity (GHSV) = 9000 mL h−1 gcat−1). This represents a 125 °C reduction in operating temperature compared to conventional Co-based catalysts under similar conditions. Mechanistic investigations using isotopic labeling and in-situ diffuse reflectance infrared Fourier transform spectroscopy reveal that the synergistic modification of Ce and N creates a unique LA-L(A+B)-LB active site configuration. This structure significantly lowers the Schottky barrier at the metal-support interface, promoting facile hydrogen spillover. Crucially, the reaction proceeds via an interfacial Mars-van Krevelen mechanism, a stark contrast to the traditional Langmuir-Hinshelwood pathway on conventional Co catalysts. This study provides new insights for developing low-temperature Co-based catalysts for ammonia decomposition.