Ce-modified Ni nanoparticles encapsulated in SiO2 for COx-free hydrogen production via ammonia decomposition

•Core-shell structured Ce–NiO@SiO2 catalysts were prepared for hydrogen production via ammonia decomposition.•Ce-modification resulted in the high-surface-area catalysts with small sized Ni particles, enhancing the activity.•SiO2 shell effectively prevented the Ni catalysts from sintering during ammonia decomposition.•High catalytic activity and stability of the core–shell structured Ce–NiO@SiO2 catalysts were achieved.

Ce-modified Ni nanoparticles encapsulated in SiO2 were prepared, and used as efficient catalyst for COx-free hydrogen production via ammonia decomposition. Due to the introduction of an appropriate amount of Ce, the catalyst's properties were altered by enhancing NiO dispersion and reducing NiO particle size with high-surface-area. And the catalysts are highly stable owing to the SiO2 shell preventing the enwrapped core particles from aggregation at high reaction temperature. High catalytic activity of the almost total conversion of ammonia at 650 °C with H2 producing rate of 33.24 mmol gcat−1 min−1 is achieved on the prepared stable core–shell structured Ce–Ni@SiO2 catalysts, which is higher than Ce–NiO and Ni@SiO2 catalysts.

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