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Natural Kaolin-Based Ni Catalysts for CO2Methanation: On the Effect of Ce Enhancement and Microwave-Assisted Hydrothermal Synthesis
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Document Title
Natural Kaolin-Based Ni Catalysts for CO2Methanation: On the Effect of Ce Enhancement and Microwave-Assisted Hydrothermal Synthesis
Author
Aimdate K.,Srifa A.,Koo-Amornpattana W.,Sakdaronnarong C.,Klysubun W.,Kiatphuengporn S.,Assabumrungrat S.,Wongsakulphasatch S.,Kaveevivitchai W.,Sudoh M.,Watanabe R.,Fukuhara C.,Ratchahat S.
Name from Authors Collection
Affiliations
Department of Chemical Engineering, Faculty of Engineering, Mahidol University, Nakhon Pathom, 73170, Thailand; Synchrotron Light Research Institute, Nakhon Ratchasima, 30000, Thailand; National Nanotechnology Center (NANOTEC), National Science and Technology Development Agency, Pathum Thani, 12120, Thailand; Center of Excellence in Catalysis and Catalytic Reaction Engineering, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, 10330, Thailand; Bio-Circular-Green-Economy Technology and Engineering Center, BCGeTEC, Department of Chemical Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok, 10330, Thailand; Department of Chemical Engineering, Faculty of Engineering, King Mongkut's University of Technology North Bangkok, Bangkok, 10800, Thailand; Department of Chemical Engineering, National Cheng Kung University, Tainan City, 70101, Taiwan; Hierarchical Green-Energy Materials (Hi-GEM) Research Center, National Cheng Kung University, Tainan City, 70101, Taiwan; Amano Institute of Technology, Hamamatsu, Shizuoka, 431-1305, Japan; Department of Applied Chemistry and Biochemical Engineering, Graduate School of Engineering, Shizuoka University, Hamamatsu, Shizuoka, 432-8561, Japan
Type
Article
Source Title
ACS Omega
ISSN
24701343
Year
2021
Volume
6
Issue
21
Page
13779-13794
Open Access
All Open Access, Gold, Green
Publisher
American Chemical Society
DOI
10.1021/acsomega.1c01231
Abstract
Natural kaolin-based Ni catalysts have been developed for low-temperature CO2 methanation. The catalysts were prepared via a one-step co-impregnation of Ni and Ce onto a natural kaolin-derived metakaolin using a microwave-assisted hydrothermal method as an acid-/base-free synthesis method. The influences of microwave irradiation and Ce promotion on the catalytic enhancement including the CO2 conversion, CH4 selectivity, and CH4 yield were experimentally investigated by a catalytic test of as-prepared catalysts in a fixed-bed tubular reactor. The relationship between the catalyst properties and its methanation activities was revealed by various characterization techniques including X-ray fluorescence, X-ray diffraction, Brunauer-Emmett-Teller, scanning electron microscopy, selected area electron diffraction, transmission electron microscopy, elemental mapping, H2 temperature-programmed reduction, and X-ray absorption near-edge structure analyses. Among the two enhancement methods, microwave and Ce promotion, the microwave-assisted synthesis could produce a catalyst containing highly dispersed Ni particles with a smaller Ni crystallite size and higher catalyst reducibility, resulting in a higher CO2 conversion from 1.6 to 7.5% and a better CH4 selectivity from 76.3 to 79.9% at 300 °C. Meanwhile, the enhancement by Ce addition exhibited a great improvement on the catalyst activities. It was experimentally found that the CO2 conversion increased approximately 7-fold from 7.5 to 52.9%, while the CH4 selectivity significantly improved from 79.9 to 98.0% at 300 °C. Though the microwave-assisted synthesis could further improve the catalyst activities of Ce-promoted catalysts, the Ce addition exhibited a more prominent impact than the microwave enhancement. Cerium oxide (CeO2) improved the catalyst activities through mechanisms of higher CO2 adsorption capacity with its basic sites and the unique structure of CeO2 with a reversible valence change of Ce4+ and Ce3+ and high oxygen vacancies. However, it was found that the catalyst prepared by microwave-assisted synthesis and Ce promotion proved to be the optimum catalyst in this study. Therefore, the present work demonstrated the potential to synthesize a nickel-based catalyst with improved catalytic activities by adding a small amount of Ce as a catalytic promoter and employing microwave irradiation for improving the Ni dispersion. © 2021 The Authors. Published by American Chemical Society.
Industrial Classification
Knowledge Taxonomy Level 1
Knowledge Taxonomy Level 2
Knowledge Taxonomy Level 3
License
CC BY-NC-ND
Rights
Author
Publication Source
Scopus