Dehydrogenation of homocyclic liquid organic hydrogen carriers (LOHCs) over Pt supported on an ordered pore structure of 3-D cubic mesoporous KIT-6 silica

• Published in: Applied catalysis. B, Environmental Environmental, 2022-06, Vol.307, p.121169, Article 121169
• Main Authors: Ahn, Chang-Il, Kwak, Yeonsu, Kim, Ah-Reum, Jang, Munjeong, Badakhsh, Arash, Cha, Junyoung, Kim, Yongmin, Jo, Young Suk, Jeong, Hyangsoo, Choi, Sun Hee, Nam, Suk Woo, Yoon, Chang Won, Sohn, Hyuntae
• Format: Article
• Language: English
• Subjects: Aluminum oxide; Catalysts; Catalytic activity; Coking; Dehydrogenation; Hydrogen; Hydrogen production; KIT-6; Liquid organic hydrogen carriers; Methylcyclohexane; Molecular structure; Ordered mesoporous silica; Particle size; Particle size distribution; Reaction time; Selectivity; Silica; Silicon dioxide; Size distribution
• ISSN: 0926-3373; 1873-3883
• DOI: 10.1016/j.apcatb.2022.121169

Pt supported on ordered mesoporous silica (KIT-6) catalyst was examined for the dehydrogenation of homocyclic liquid organic hydrogen carriers (LOHCs, 1: MCH, 2: hydrogenated biphenyl-based eutectic mixture (H-BPDM)) conditions. The longer pore-residence time of the MCH molecules in the 3D bicontinuous pore structure of the Pt/KIT-6 catalyst strongly affected the catalytic activity because a higher MCH concentration was achieved in the vicinity of the Pt active sites. Pt/KIT-6 catalyst exhibited a higher surface area, pore volume, and Pt dispersion with narrower particle size distribution (average Pt particle size: ~1.3 nm). Therefore, higher LOHC conversion with faster hydrogen production occurred, with a higher hydrogen selectivity over Pt/KIT-6 compared with Pt/SiO2 and Pt/Al2O3. Long-term experiment results indicated that the Pt/KIT-6 catalytic activity was stable over the reaction time than that of the other catalysts. No significant structural collapse occurred in KIT-6 during the dehydrogenation. Carbon coking was observed for all three samples. [Display omitted] •Pt was supported on order mesoporous silica with a 3-D pore structure (KIT-6).•Pt/KIT-6 exhibited excellent LOHC dehydrogenation activity and high H2 selectivity.•Pt/Al2O3 and Pt/SiO2 revealed formation of partially dehydrogenated products.•Pt was confined in the KIT-6 mesopores showing narrow particle size distribution.•Longer pore-residence time was achieved attributed to the 3-D structure of KIT-6.