Exploring the ternary interactions in Cu–ZnO–ZrO2 catalysts for efficient CO2 hydrogenation to methanol

Abstract

The synergistic interaction among different components in complex catalysts is one of the crucial factors in determining catalytic performance. Here we report the interactions among the three components in controlling the catalytic performance of Cu–ZnO–ZrO2 (CZZ) catalyst for CO2 hydrogenation to methanol. The in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) measurements under the activity test pressure (3 MPa) reveal that the CO2 hydrogenation to methanol on the CZZ catalysts follows the formate pathway. Density functional theory (DFT) calculations agree with the in situ DRIFTS measurements, showing that the ZnO–ZrO2 interfaces are the active sites for CO2 adsorption and conversion, while the presence of metallic Cu is also necessary to facilitate H2 dissociation and to provide hydrogen resource. The combined experiment and DFT results reveal that tuning the interaction between ZnO and ZrO2 can be considered as another important factor for designing high performance catalysts for methanol generation from CO2.

Rational Engineering of Multilayered Co3O4/ZnO Nanocatalysts through Chemical Transformations from Matryoshka‐Type ZIFs

“…Figure a,b displays CO 2 adsorption spectra before and after the desorption process (viz., N 2 purge) over five‐layer and six‐layer ZDMOs. Under CO 2 flows, the absorption bands in the range 3600–3800 cm −1 could be assigned to the combinational bands (i.e., rovibrational bands) overtones of the gaseous CO 2 , which is a linear triatomic molecule with three basic vibrations . The intense bands at 2360 and 2343 cm −1 can be ascribed to stretching vibrations of the gaseous CO 2 .…”

Synthesis of monocarboxylic acids via direct CO2 conversion over Ni–Zn alloy catalysts

“…Furthermore, this is the rst reported synthesis of PA via the direct catalytic hydrogenation of CO 2 . Even though ZnO is known to be an active catalyst for the synthesis of methanol via the hydrogenation of CO and CO 2 , the formation of methanol or higher alcohols over Ni-Zn alloy catalysts has not been reported 6,54,55 .…”

“…The direct conversion of CO 2 into fuels and chemicals using renewable H 2 that can be produced via water electrolysis or biomass conversion has received considerable attention because of its potential to mitigate global warming [1][2][3] . Different catalysts have been developed to effectively convert CO 2 into C 1 chemicals (e.g., methanol [4][5][6] , CO 7,8 , CH 4 9, 10 , and formic acid [11][12][13] ). However, because of the inherent inertness of CO 2 (∆G 0 298K = −394.4 kJ mol − 1 ) and high energy barrier of the C-C coupling reaction 14 , it is challenging to directly synthesize long-chain hydrocarbons and oxygenated species from CO 2 , with high selectivity.…”

Carbon‐Modified CuO/ZnO Catalyst with High Oxygen Vacancy for CO2 Hydrogenation to Methanol

“…As for the catalytic mechanism over Cu‐based catalysts, many researchers state that the metal–carrier interaction is the active site of methanol synthesis . The aforementioned characterizations of CO 2 ‐TPD (Figure ) and H 2 ‐TPD (Figure ) show that the adsorption and desorption of CO 2 are related to ZnO, and the adsorption and desorption of H 2 is related to Cu.…”

“…So H species migrating from the Cu surface to the carbon species that are adsorbed on the ZnO and Cu–ZnO interact to promote the synthesis of methanol. In addition, formate (HCOO − ) and methoxy (CH 3 O − ) are generally recognized as intermediates in the hydrogenation of CO 2 to methanol, in which the formation of formate (CO 3 2− + H* ↔ HCOO − + O 2− ) and formate hydrogenation (HCOO − + 4 H* ↔ CH 3 O − + H 2 O) is the rate‐determining step of methanol synthesis, and methoxy intermediates are the precursor of methanol synthesis, which is hydrolyzed to produce methanol (CH 3 O − + H 2 O ↔ CH 3 OH + OH − ) . The production of formate and methoxy intermediates depends on the hydrogenation process, so hydrogen spillover plays a critical role in the hydrogenation of CO 2 to methanol, which is a necessary step for the formation of intermediate products.…”