Tandem Catalysis for CO₂ Hydrogenation to C₂–C₄ Hydrocarbons

Abstract

Conversion of carbon dioxide to C-C hydrocarbons is a major pursuit in clean energy research. Despite tremendous efforts, the lack of well-defined catalysts in which the spatial arrangement of interfaces is precisely controlled hinders the development of more efficient catalysts and in-depth understanding of reaction mechanisms. Herein, we utilized the strategy of tandem catalysis to develop a well-defined nanostructured catalyst CeO-Pt@mSiO-Co for converting CO to C-C hydrocarbons using two metal-oxide interfaces. C-C hydrocarbons are found to be produced with high (60%) selectivity, which is speculated to be the result of the two-step tandem process uniquely allowed by this catalyst. Namely, the Pt/CeO interface converts CO and H to CO, and on the neighboring Co/mSiO interface yields C-C hydrocarbons through a subsequent Fischer-Tropsch process. In addition, the catalysts show no obvious deactivation over 40 h. The successful production of C-C hydrocarbons via a tandem process on a rationally designed, structurally well-defined catalyst demonstrates the power of sophisticated structure control in designing nanostructured catalysts for multiple-step chemical conversions.

Shape‐Selective Zeolites Promote Ethylene Formation from Syngas via a Ketene Intermediate

“…Remarkably,t he selectivity of ethylene alone (excluding CO 2 )r eaches as high as 83 %, which is much higher than the 23 %o btained over ZnCrO x -MSAPO (see Figure S2). [3a] Such an ethylene selectivity is unprecedented in any other direct syngas conversion process [2,12] and also higher than that of the MTO processes reported so far. [1,13] Furthermore,t he selectivity of the byproduct CH 4 is only 5%.F igure 1B shows that CO conversion increases with the temperature and reaches 11 % at 390 8 8Cw hile C 2 = selectivity still remains at 71 %.…”

“…[1] In comparison, direct conversion of syngas into ethylene is attractive because it involves fewer operation units.This transformation has been under extensive study for over 50 years with efforts mainly focusing on modification of Fe-a nd Co-based FTS catalysts. [2] Despite significant pro-gress, [2c,e, 3] the C 2 = selectivity remains low and the highest C 2 selectivity (including C 2 = and ethane C 2 8 8)i sp redicted to be 30 %b yt he Anderson-Schultz-Flory (ASF) model in the conventional FTS (see Figure S1 in the Supporting Information).Previous studiesd emonstratedt hataselectivity of ethane as high as 83 %c an be obtained by applying ZSM-5 impregnatedw ithC r, Zn,a nd Al,b ut no ethylene,w hich is obviouslyamuch more valuable C 2 product, wasdetected. [4] A series of bifunctional catalystsw erer eportedt og iveC 2 -C 4 paraffinsa sp roducts, buta lson oe thylene.…”

Hydrogenation of Carbon Dioxide to C2–C4 Hydrocarbons Catalyzed by Pd(PtBu3)2–FeCl2 with Ionic Liquid as Cocatalyst

“…Although much progress has been made, the IL-mediated CO 2 hydrogenation to hydrocarbons has rarely been reported in the literature. Various ILs and solvents were examined in the hydrogenation of CO 2 catalyzed by Pd(PtBu 3 ) 2 and FeCl 2 in the presence of Xantphos, and the resultsa re listed in Ta ble 1a nd Table S1 in the Supporting Information. In this protocol, the combination of 1-butyl-3methylimidazolium hexafluorophosphate ( CO 2 = 2:1) at 9MPa, ay ield of 1.08 C-mmol was achieved, together with as electivity towards C 2 -C 4 hydrocarbons up to 98.3 C-mol %, much highert han those obtainedo ver the catalysts reported in the literature.…”

“…C 2 -C 4 hydrocarbonsa re the crucial chemical feedstocks for synthesizing value-added products such as detergents, polymerm aterials, and drugs. [2] The selective hydrogenation of CO 2 to C 2 -C 4 hydrocarbons is ap romising path, but it imposes major technological challenges owing to the thermodynamic stabilitya nd kinetic inertness of CO 2 and suffers from low selectivity towards to C 2 -C 4 hydrocarbons. [3] So far,s ome heterogeneousc atalysts have been developed for hydrogenation of CO 2 to C 2 -C 4 alkanes.…”

“…[4] In addition, the catalytic system wasstable and reusable. Various ILs and solvents were examined in the hydrogenation of CO 2 catalyzed by Pd(PtBu 3 ) 2 and FeCl 2 in the presence of Xantphos, and the resultsa re listed in Ta ble 1a nd Table S1 in the Supporting Information. It is clear that the ILs significantly influenced the reaction.…”