Production of methanol from carbon dioxide using palladium-copper-zinc loaded on MCM-41: Comparison of catalysts synthesized from flame spray pyrolysis and sol-gel method using silica source from rice husk ash

Carbon dioxide hydrogenation is an industrially important reaction to convert excess carbon dioxide to value added compounds such as hydrocarbon, carbon monoxide, and methanol. In this study, copper (Cu)-zinc (Zn) loaded on Mobil Composition of Matter No. 41 (MCM-41) promoted with palladium (Pd) was used as a catalyst in carbon dioxide hydrogenation reaction for methanol production. The MCM-41 supports synthesized via sol-gel process and flame spray pyrolysis were compared regarding their use in carbon dioxide hydrogenation. The effect of metal loading and the role of palladium were investigated. The carbon dioxide hydrogenation was conducted under conditions-T = 250 degrees C, P = 25 bar, hydrogen:carbon dioxide = 3:1 (by volume). The experimental results show that the MCM-41 was successfully synthesized by both methods. The promoted catalysts with palladium show the changes in catalyst morphology, temperature reduction, specific surface area, average pore size, and pore volume. The promoted catalysts also exhibit higher performance than the catalyst without promoter. The catalyst containing 15% palladium, 25% copper, and 25% zinc (by weight) loaded on MCM-41 gave the highest performance of 25% methanol selectivity and 112 g/kg(cat)h space time yield of methanol due to the synergetic effect of copper-palladium and high dispersion of metals that promoted the methanol production. (C) 2016 Elsevier Ltd. All rights reserved.