Graphene aerogel-supported ruthenium nanoparticles for COx-free hydrogen production from ammonia

• Published in: Applied catalysis. A, General General, 2021-01, Vol.610, p.117969, Article 117969
• Main Authors: Kocer, Tolga, Oztuna, F. Eylul Sarac, Kurtoğlu, Samira Fatma, Unal, Ugur, Uzun, Alper
• Format: Article
• Language: English
• Subjects: Aerogels; Ammonia; Ammonia decomposition; Catalysts; Conversion; COx-free hydrogen production; Electron density; Graphene; Graphene aerogel; Hydrogen; Hydrogen production; Nanoparticles; Promoter; Ruthenium; Supported ruthenium nanoparticles
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/j.apcata.2020.117969

[Display omitted] •Ruthenium was highly dispersed on graphene aerogel (GA) at high loadings.•13.6 wt% Ru on GA provided 71.5 % NH3 conversion at 450 °C with high stability.•K addition increased both Ru dispersion and electron density over Ru.•K-promoted catalyst displayed a stable and a record high activity at 450 °C. Ruthenium was highly dispersed on graphene aerogel (GA) at high loadings to achieve high performance in COx-free hydrogen production from ammonia. Catalytic performance measurements on ammonia decomposition showed that the GA-supported catalyst with a Ru loading of 13.6 wt% provides an ammonia conversion of 71.5 % at a space-velocity of 30,000 ml NH3 gcat−1 h−1 and at 450 °C, corresponding to a hydrogen production rate of 21.9 mmol H2 gcat−1 min−1. The addition of K increased the ammonia conversion to a record high value of 97.6 % under identical conditions, reaching a hydrogen generation rate of 30.0 mmol H2 gcat−1 min−1, demonstrated to be stable for at least 80 h. A comparison of the turnover frequencies of catalysts indicated that this increase in performance upon the addition of K originated from an increase in the number of the active Ru sites and the corresponding electron density available for reaction.