Effect of lanthanum loading in Fe-K/La-Al2O3 catalysts for CO2 hydrogenation to hydrocarbons

Abstract

Lanthanum-modified alumina supports prepared by the impregnation method have been used as supports for potassium-promoted iron catalysts in CO 2 hydrogenation. The catalysts have been characterized by X-ray diffraction, CO 2 chemisorption, temperature-programmed reduction (TPR) and temperature-programmed decarburization (TPDC) techniques. The selectivity towards total hydrocarbons and lower olefins (C 2 -C 4 ) was found to increase with increase in lanthanum content up to 4 wt% in Fe-K/La-Al 2 O 3 catalysts and to decrease above this lanthanum content. The TPR profiles of the catalysts of lanthanum-modified Al 2 O 3 shows the reduction of Fe 2 O 3 to iron(0) follows a threestage reduction mechanism through formation of the FeO phase. The TPDC profiles show the formation of three types of carbide species on the catalysts during the reaction. The activities of the catalysts are correlated with physico-chemical characteristics of the catalysts.

Recent advances in catalytic hydrogenation of carbon dioxide

“…Other additives including Zr, Zn, Mg, Ru, and La have also been investigated but promoting effect is nearly negligible. 106,127,129,[139][140][141][142] Iron-based catalysts dispersed on different supports have also been examined extensively and the product distributions are greatly dependent on supporting materials. 106 The support tends to act purely as a stabilizer to avoid sintering of active particles during the reaction.…”

Catalyst Development for CO2 Hydrogenation to Fuels

“…Among the oxides, Al 2 O 3 , SiO 2 and TiO 2 , alumina exhibited a better performance in terms of activity and low methane selectivity 3. Mixed oxides of aluminium and lanthanum16 or MgO17 improved the performance of supported Fe–K. Zeolite Y has also been applied as a support for alkaline‐doped Fe 18.…”

CO2 Hydrogenation: Supported Nanoparticles vs. Immobilized Catalysts

“…CO + CO → C + CO 2 (7) The role of promoters, such as K, [37] Na, [37b] Li, [37b] Mn [37a,38] and La [39] species, is considered to enhance the activity of the catalyst in RWGS (due to improvement of CO/CO 2 adsorption) and the carburization of Fe or Co species. In addition, Mn has R=Cl, TON=7200 2-(b) Jessopetal., 2002 [42b] R=OAc, TOF=95000 h [46] CO 2 to formate TOF=99100h -1 N ( t Bu) 2 P P( t Bu) 2 Ru CO Cl H 9 Pidko et al, 2014 [44] CO 2 to formate TOF=1892000 h -1 N N P( t Bu) 2 Ru CO H Cl 12 Milstein et al, 2015 [49] Captured CO 2 (oxazolidinone) to methanol Yield: 92% Fig.…”