Egg-shell-type Ni supported on MgAl2O4 pellets as catalyst for steam methane reforming: Enhanced coke-resistance and pellet stability

• Published in: Catalysis today Vol. 352; pp. 157 - 165
• Main Authors: Cho, Eunkyung, Yu, Yeon Jeong, Kim, Youngji, Phan, Tuan Ngoc, Park, Dasom, Ko, Chang Hyun
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.08.2020
• Subjects: Egg-shell-type catalysts; High coke resistance; Low steam-to-carbon ratio; Nickel-based catalysts; Steam methane reforming; Tube-shaped pellet catalysts; Low steam-to-carbon ratio; Egg-shell-type catalysts; Nickel-based catalysts; Tube-shaped pellet catalysts; High coke resistance; Steam methane reforming
• ISSN: 0920-5861; 1873-4308
• DOI: 10.1016/j.cattod.2019.11.013

[Display omitted] •Nickel-based egg-shell-type catalyst was prepared on tube-shaped MgAl2O4 pellet.•Prepared catalysts showed comparable catalytic activity in steam methane reforming.•The egg-shell-type catalyst exhibited superior coke resistance and pellet stability. The steam methane reforming (SMR) reaction generally occurs on the surface of pellet catalysts due to the high reaction rate. We herein prepared egg-shell-type pellet catalysts using tube-shaped MgAl2O4 pellets as a support for effective utilization of the catalytically active component (nickel) by selectively localizing the metallic nickel particles in the outer region of the pellets. Formation of the egg-shell-type catalysts was confirmed by cross-sectional imaging and scanning electron microscopy-energy dispersive X-ray spectroscopy. As a comparison, the homo-type catalysts, in which nickel was uniformly distributed throughout the pellet, were also prepared. In the SMR reaction with a steam to carbon ratio (S/C) of 3, the catalytic activity of the egg-shell-type catalyst with Ni loading of 3.5 wt.% matched or exceeded that of the homo-type catalyst with Ni loading of 5 wt.% despite the lower Ni loading of the former, over the entire weight hourly space velocity range (6,000–24,000 mL·gcat–1 h–1). To rapidly evaluate coke formation with the given pellet catalysts, experiments were performed with an S/C of 0.5. Under this condition, the methane conversion of the given catalysts was similar. However, the egg-shell-type catalysts showed better coke resistance and pellet stability than the homo-type catalyst. Overall, the egg-shell-type catalysts exhibit excellent properties in terms of long-term stability and carbon resistance. Thus, the egg-shell-type catalysts are more suitable for SMR reactions than the conventional homo-type catalyst.