Alkaline earth metal promoted hydrogen production from ammonia decomposition over Ni/La2O3-based catalysts

• Published in: Applied catalysis. B, Environmental Environmental, 2024-07, Vol.348, p.123844, Article 123844
• Main Authors: Guo, Xiao-Yu, Wang, Jun-Hao, Zhang, Qian, Li, Ting-Zhou, Dong, Hao, Jia, Chun-Jiang, Li, Chen, Zhang, Ya-Wen
• Format: Article
• Language: English
• Subjects: Alkaline earth metal; Ammonia decomposition; Hydrogen production; Ni-based catalysts; Promoter
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2024.123844

The addition of appropriate promoters can modulate the chemical characteristics of heterogeneous catalysts so as to improve and optimize their catalytic performance. Here, we introduced SrO as both a support and a promoter to optimize the activity of Ni/La2O3-based catalysts for the ammonia decomposition reaction. A series of La1−xSrxNiO3-δ-600H2 catalysts were prepared by reducing La1−xSrxNiO3-δ (x = 0, 0.2, 0.33, 0.5, 0.67, 0.8, and 1) precursors under a H2/N2 atmosphere. The La0.5Sr0.5NiO3-δ-600H2 catalyst with a proper amount of Sr exhibited outstanding ammonia decomposition conversion rate (87.7%) and hydrogen production rate (29.4 mmol·gcat−1·min−1) at 550 °C with a GHSV of 30,000 mL·gcat−1·h−1. The presence of Sr induced the Ni species to be situated in a more electro-negative environment, thus facilitating the recombination of N atoms and N2 desorption; whereas Ni nanoparticles could be evenly dispersed by La2O3, which rendered the catalyst with high stability. Briefly, the synergistic effect of Sr increasing electron density of Ni species and La2O3 stabilizing Ni nanoparticles has greatly enhanced the catalytic performance. This work has demonstrated a new variety of promising noble metal-free catalysts toward the eventual application in hydrogen production from ammonia decomposition reaction. [Display omitted] •Catalysts of Ni/La2O3 with SrO as a promoter were prepared by reducing La1−xSrxNiO3-δ derived from a sol-gel method.•The catalyst with a proper amount of Sr (LaSr = 1:1) exhibited outstanding ammonia decomposition performance.•Sr increasing Ni species electron density along with La2O3 stabilizing Ni nanoparticles enhanced the catalytic performance.