Methanation of CO2 over zeolite-promoted Ni/Al2O3 nanocatalyst under atmospheric pressure

Abstract

Zeolite was added at different weight percentages as a promoter to 10% Ni/Al2O3 and tested under atmospheric pressure for CO2 methanation for the first time. The influence of operational conditions and stability of the catalysts were investigated. The highest CO2 conversion of 99% and CH4 selectivity of 56% were achieved with 2% zeolite added catalyst at 350 degrees C reaction temperature. The textural and morphological characteristics of the non-promoted and zeolite promoted catalysts were established with Scanning electron microscopy, Fourier transform infrared spectrophotometer, BET analyser and X-Ray diffractometer. The addition of 2% zeolite increased the specific surface area of the catalyst while sustaining similar Ni metal surface area to the non-promoted one. However, at higher zeolite content, the CH4 selectivity reduced considerably due to the reduced Ni dispersion and specific surface area. The calcination temperature of 400 degrees C, H-2/CO2 ratio of 4, GHSV of 72,000 SmL(gcat h)(-1) resulted in the highest CH4 selectivity. The 2% zeolite added catalyst demonstrated superior resistance to deactivation in comparison to the non-promoted catalyst showing potential as a low-cost catalyst for further optimization studies.