Characterization and modelling optimization on methanation activity using Box-Behnken design through cerium doped catalysts

Catalytic methanation reaction has been a promising technique for the conversion of CO2 to valuable fuel product, CH4 and thus reduces the emission of CO2 to the environment. Many catalysts have been investigated by this method yet some carbon depositions have occurred during reaction which leading to low conversion rate of CO2 to CH4. Therefore, cerium catalyst has been applied in this study for the investigation of catalytic activity utilizing response surface methodology (RSM) method (Box-Behnken Design) in order to achieve the highest CO2 conversion. The potential trimetallic oxide catalyst of Ru/Mn/Ce (5:35:60)/Al2O3 was chosen and the experimental parameters used were calcination temperature of 600–800 °C, ratio based loadings of 60–80 wt%, and catalyst dosage of 3–7 g with CO2 conversion to CH4 as a respond. The RSM optimum parameter of calcination temperature of 697.47 °C, ratio of 60.38% and catalyst dosage 6.94 g was tested. At these conditions, the results were verified experimentally (99.98% CO2 conversion), which was accurately close to the predicted value (100% CO2 conversion). Ru/Mn/Ce (5:35:60)/Al2O3 catalyst revealed the active species of CeO2 in XRD analysis with oxidation state Ce 4+ as supported by ESR analysis. When the calcination temperature was increased, the surface area decreases as observed in nitrogen adsorption supported with larger particle size as shown in FESEM. The reducibility of cerium catalyst was started at lower temperature

Optimization by Box-Behnken design of in-situ carbon dioxide conversion using lanthanum oxide

Lanthanum oxide based catalyst was revealed as one of potential catalyst to convert carbon dioxide to wealth product methane in simulated natural gas. To produce higher conversion of carbon dioxide, the Response Surface Methodology utilizing Box-Behnken design (BBD) was used to optimize the lanthanum oxide based catalysts by three critical parameters which were calcination temperature, based ratio and catalyst dosage. The maximum CO2 conversion was achieved at 1000oC calcination temperature using 7 g of catalyst for 60% based loading. The optimization result from BBD is in good agreement with experimental data. The optimize parameters gave 99% of CO2 conversion determined using Fourier Transformation Infrared (FTIR) and yielded about 50% of CH4 at reaction temperature of 400 °C. X-ray Diffraction (XRD) analysis showed an amorphous structure with RuO2 as active species and Field Emission Scanning Electron Microscope (FESEM) illustrated the catalyst surface was covered with small and dispersed particles with undefined shape. EDX analysis revealed that when the calcination temperature was increased, the mass ratio of Ru increased

Catalytic methanation over nanoparticle heterostructure of Ru/Fe/Ce/y-Al2O3 catalyst: performance and characterisation

A novel trimetal-oxides (Ru/Fe/Ce) supported on γ-Al2O3 catalyst was synthesised by simple impregnation method and the activity was investigated at atmospheric pressure. The results showed that Ru/Fe/Ce (5:10:85)/γ-Al2O3 catalyst calcined at 1000 °C for 5 h was effective and gave a 97.20% of CO2 conversion at 275 °C with 93.5% of CH4 formation. The catalyst possesses medium-strength basic sites with the best reduction temperature of <200 °C. The mesoporous structure was covered with small, dispersed particles of spherical in shape. The catalyst is formed by nanoparticles below 10 nm with a surface area of 51 m2/g. The physicochemical analyses showed that the active sites of the potential catalyst Ru/Fe/Ce (5:10:85)/γ-Al2O3 are RuO2 (tetragonal), Fe2O3 (rhombohedral), γ-Al2O3 (cubic), and CeO2 (cubic), with a good distribution on the catalyst surface