CO ₂ Methanation over Nickel Supported on Zeolite 5A Pellets Produced by Different Binders

Nickel supported on a zeolite Linde Type A 5A (zeolite LTA 5A) catalyst (Ni/zeolite LTA 5A) was fabricated into cylindrical pellets using two types of binders: methylcellulose (MC) with poly(vinyl alcohol) (PVA) and glutinous flour (GF). Carbon dioxide methanation was conducted under atmospheric pressure at 200–500 °C. The gas hourly space velocity (GHSV) was varied from 1,125 to 15,000 h–1, corresponding to volumetric flow rates of 60–500 mL/min. The conversion of carbon dioxide to methane decreased as GHSVs increased. Fabricated catalysts produced higher methane yields than the catalyst powder, with CO2-to-CH4 conversion rates of 70–90% and 10–90%, respectively. The CO2 conversion of the catalyst with MC+PVA approached 90% at 400 °C, superior to that of the catalyst with GF, which reached 84% at the same temperature and a volumetric flow rate of 60 mL min–1. The most active temperature for CO2 methanation was 400 °C, and nearly all catalysts were selective to methane, with selective rates exceeding 80%. The stabilities of the fabricated catalysts were tested over 96 h. The stability of the catalyst with MC+PVA was noncomparable to that of the catalyst with GF, since the catalyst with MC+PVA exhibited a 1–6% reduction in activity after 36 h, owing to nickel metal sintering, whereas the catalyst with GF binder exhibited minor fluctuations and remained stable within 96 h. The employed catalysts lost their configurated shapes, existing only as small particles due to binder decomposition.