Direct synthesis of ethanol via CO₂ hydrogenation using supported gold catalysts

Abstract

An efficient titania supported Au nanocluster (NC) has been prepared for the direct synthesis of useful EtOH from CO and H. The unique creation of an excellent synergistic effect between Au NCs and the underlying TiO support, especially the anatase crystal phase with abundant oxygen vacancies, can achieve the high performance for EtOH synthesis under moderate and practical conditions.

Remarkable Carbon Dioxide Hydrogenation to Ethanol on a Palladium/Iron Oxide Single‐Atom Catalyst

“…For the 0.1Pd/Fe 3 O 4 catalyst, the selectivity towards ethanol was 97.5 % at 300 °C, and the activity was 413 mmol EtOH g Pd −1 h −1 (Table , entry 1). This result is among the highest catalytic activities ever reported for the synthesis of ethanol from CO 2 hydrogenation . At increasing temperatures, the selectivity towards ethanol decreased at the expense of CO, but propanol and trace amounts of butanol were produced, in particular at 400 °C (Table , entries 2 and 3).…”

“…[6] Alternatively,s upported catalysts based on Rh [7] and Pt [8] as well as CoMoS [9] have also shown the ability to convert syngas into ethanol. Recently,s mall Au nanoparticles supportedo nT iO 2 capable of simultaneously activating H 2 and CO 2 , [10] as well as bimetallic Pd-Cu nanoparticles supported on TiO 2 and active forC ÀCc oupling, [11] have shown high selectivity towarde thanol in the hydrogenation of CO 2 in batch-operation mode. Motivated by recent advances in single-atom catalysis (SAC), [12] herein we report on aP d/Fe 3 O 4 catalyst containing Pd single atoms that exhibitso utstanding selectivity and yield toward ethanol in CO 2 hydrogenation under mild conditions.Three Pd/Fe 3 O 4 catalysts werep repared containing 0.11, 0.38, and 3.0 wt %P d, as measured by inductively coupled plasma opticale missions pectrometry (ICP-OES).…”

“…The series of Pd/Fe 3 O 4 samples was first investigateda sp repared for the hydrogenation of CO 2 at 300-400 8Ca nd atmospheric pressure under dynamic conditions in ap acked-bed reactor with af eed gas composition of 10 all the products present, and the activity values normalized on the basis of the weight of Pd or on the basis of the calculated surfacea rea of Pd are compiled in Ta ble 1( entries 1-9). Remarkably,t he Pd/Fe 3 O 4 catalysts showed,i na ddition to CO, outstanding selectivity towards the formationo fa lcohols, particularly ethanol.…”

“…This result is among the highestc atalytic activities ever reported for the synthesis of ethanolf rom CO 2 hydrogenation. [10,11] At increasing temperatures,t he selectivity towards ethanold ecreased at the expense of CO, but propanol andt race amounts of butanol were produced, in particular at 400 8C( Ta ble 1, entries 2a nd 3). This was accompanied by an increase in CO 2 conversion.T he high selectivity towarde thanol and the total absence of hydrocarbon production on 0.1Pd/Fe 3 O 4 are remarkable.…”

“…This was accompanied by an increase in CO 2 conversion.T he high selectivity towarde thanol and the total absence of hydrocarbon production on 0.1Pd/Fe 3 O 4 are remarkable. Ta king into account that ab lank run overt he bare Fe 3 O 4 support yielded only CO at high temperatures (Table1,e ntries [10][11][12], it is likely that the first step in the reaction is the transformation of CO 2 into CO over the Fe 3 O 4 support through the RWGS reaction, and then Pd assists in the CÀCc oupling. This schemei s reinforced by the fact that higher partial pressures of CO at high temperatures favor the formation of propanol, possibly through aC O-insertion-type mechanism.…”