Natural Kaolin Derived Ruthenium Supported Nanoporous Geopolymer: A Sustainable Catalyst for CO2 Methanation

Abstract

Addressing the serious concern of excessive CO2 emission, CO2 methanation reaction for converting environmental CO2 to methane is a suitable way. Methane can be used not only as a fuel but also as a hydrogen carrier. In this study, the geopolymer is explored as a support which is synthesized using natural kaolin (GNK). This geopolymer support is used to disperse ruthenium (Ru) nanoparticles by a single-step hydrazine reduction method. The catalyst is characterized using various surface and bulk techniques. Further, the catalytic performance of ruthenium-supported Geopolymer (Ru/GNK) for CO2 methanation process is explored with varying Ru % loading and with varying flow rates. Catalyst stability is also checked for 20 h by time on stream isothermal experiment. The spent catalyst is characterized by O2-temperature programmed oxidation (O2-TPO) and X-ray photoelectron spectroscopy. Overall, the catalyst proved to be cost-effective and free from pretreatment requirement apart from the superior activity, high selectivity, and good stability.