Simultaneous impregnation of Ni and an additive via one-step melt-infiltration: Effect of alkaline-earth metal (Ca, Mg, Sr, and Ba) addition on Ni/γ-Al2O3 for CO2 methanation

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 428; p. 131393
• Main Authors: Cho, Eui Hyun, Park, Young-Kwon, Park, Kwang Yeol, Song, Dahye, Koo, Kee Young, Jung, Unho, Yoon, Wang Rai, Ko, Chang Hyun
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 15.01.2022
• Subjects: Alkaline-earth metal; Nickel catalyst; One-step melt-infiltration method; Simultaneous impregnation; Simultaneous impregnation; Nickel catalyst; Alkaline-earth metal; One-step melt-infiltration method
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2021.131393

[Display omitted] •One-step melt-infiltration method is useful for preparing high-Ni-loaded catalyst.•Alkaline earth metals (Ca, Ba, Sr, and Ba) enhance the catalytic activity of Ni/Al2O3.•Ca-Ni/Al2O3 shows the best activity among the alkaline-metal-promoted samples.•Ca addition improves the reducibility of NiO and CO2 adsorption ability. As part of carbon energy recycling, the CO2 methanation process in the power to gas technology, which converts the electricity grid into a gas grid [CO2 + 4H2 (produced by surplus electricity) → CH4] using a catalytic process, has been developed in the countries such as Germany and Denmark. To achieve an efficient catalytic process, the design of low-cost and high-efficiency catalysts is required. In this study, highly loaded Ni/Al2O3 catalysts (30 wt%) were prepared using the alkaline-earth metals (Mg, Ca, Sr, and Ba) via one-step melt-infiltration (OSMI) method. The Ni active sites were investigated, and the effectiveness of each alkaline-earth metal (Ca, Mg, Sr, and Ba) was determined. The catalytic activity was investigated in the temperature range of 275–400 °C and weight gas hourly velocity (WHSV) of 160,000 mL·gcat−1·h−1 under atmospheric pressure. Ni and alkaline-earth metals were uniformly dispersed into the pore structure of the alumina support. The average metallic Ni particle size of each catalyst was similar (~11 nm), and no severe Ni sintering was observed even at a Ni loading of 30 wt%. Mg-promoted Ni/Al2O3 catalyst was unsuitable for the OSMI method because the reduction of the Ni active sites was not completely accomplished at 400 °C. Ca-promoted Ni/Al2O3 catalyst afforded the best catalytic activity among other metal-promoted Ni/Al2O3 catalysts. Ca increased the CO2 adsorption amount and reducibility of the Ni active sites, and the optimum Ca loading was 5 wt%. However, the over-loading of Ca (10 wt%) was harmful to the catalytic activity of the Ni active sites.