Enhanced CO2 methanation at mild temperature on Ni/zeolite from kaolin: effect of metal–support interface

• Main Authors: Novia Amalia Sholeha, Novia Amalia Sholeha, Mohamad, Surahim, Bahruji, Hasliza, Prasetyoko, Didik, Nurul Widiastuti, Nurul Widiastuti, Abdul Fatah, Nor Aiza, Abdul Jalil, Aishah, Taufiq Yap, Yun Hin
• Format: Article
• Language: English
• Published: Royal Society of Chemistry 2021
• Subjects: TP Chemical technology
• Online Access: http://eprints.utm.my/id/eprint/95544/1/AishahAbdulJalil2021_EnhancedCO2MethanationAtMildTemperatureOnNiZeolite.pdf; http://eprints.utm.my/id/eprint/95544/; http://dx.doi.org/10.1039/d1ra01014j

Catalytic CO2 hydrogenation to CH4 offers a viable route for CO2 conversion into carbon feedstock. The research aimed to enhance CO2 conversion at low temperature and to increase the stability of Ni catalysts using zeolite as a support. NaZSM-5 (MFI), NaA (LTA), NaY (FAU), and NaBEA (BEA) synthesized from kaolin were impregnated with 15% Ni nanoparticles in order to elucidate the effect of surface area, porosity and basicity of the zeolite in increasing Ni activity at mild temperature of ~200 °C. A highly dispersed Ni catalyst was produced on high surface area NaY meanwhile the mesoporosity of ZSM-5 has no significant effect in improving Ni dispersion. However, the important role of zeolite mesoporosity was observed on the stability of the catalyst. Premature deactivation of Ni/NaA within 10 h was due to the relatively small micropore size that restricted the CO2 diffusion, meanwhile Ni/NaZSM-5 with a large mesopore size exhibited catalytic stability for 40 h of reaction. Zeolite NaY enhanced Ni activity at 200 °C to give 21% conversion with 100% CH4 selectivity. In situ FTIR analysis showed the formation of hydrogen carbonate species and formate intermediates at low temperatures on Ni/NaY, which implied the efficiency of electron transfer from the basic sites of NaY during CO2 reduction. The combination of Ni/NaY interfacial interaction and NaY surface basicity promoted CO2 methanation reaction at low temperature.