Infrared study of syngas adsorption on zirconia

Guglielminotti, E.

doi:10.1021/la00099a005

Cited by 76 publications

(79 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The vibrational, rotational and translational enthalpic and entropic contributions for a gas phase molecule considered as an ideal gas can be calculated with equations (S2) -(S8): [7] For an adsorbed molecule or for a surface, the rotational and translational contributions are converted into vibration modes, so that the only remaining terms are the vibrational ones -that can be calculated using the equations (S2) and (S5) -and the electronic energy E(i). For these phases, we also consider that the PVm term is very small with regard to the energetic terms, and is therefore neglected, and thus we consider H = U in this case.…”

Section: G(itp) = E(i) + Uvib(it) + Urot(it) + Utrans(it) + Pvm mentioning

confidence: 99%

“…After contacting pre-reduced Cu/ZrO2 with H2/CO2 mixture (3:1) at 230 °C and 1 bar, features appeared in the -CH ( Figure S6a) and -CO regions ( Figure S6b). The main broad -OCO features at 1593 cm -1 can be attributed to carbonate or bicarbonate (CO3* or (CO3H*), [7] and the bands at 2978, 2878, 2736, 1567 and 1387 cm -1 are characteristic of formate species adsorbed on zirconia (HCOO_ZrO2, ESI Section 5). [4d, [7][8] The presence of formate on copper cannot be excluded as a characteristic band at 1357 cm -1 is also observed.…”

mentioning

confidence: 99%

“…The main broad -OCO features at 1593 cm -1 can be attributed to carbonate or bicarbonate (CO3* or (CO3H*), [7] and the bands at 2978, 2878, 2736, 1567 and 1387 cm -1 are characteristic of formate species adsorbed on zirconia (HCOO_ZrO2, ESI Section 5). [4d, [7][8] The presence of formate on copper cannot be excluded as a characteristic band at 1357 cm -1 is also observed. [4d] Increasing the reaction pressure to 5 bars (Figure S6a-b) or higher pressures resulted in the appearance of new features at 2942, 2828 cm -1 and the characteristic C-O stretching frequencies at 1154 and 1049 cm -1 that were attributed to methoxy adsorbed on zirconia.…”

mentioning

confidence: 99%

See 2 more Smart Citations

CO₂‐to‐Methanol Hydrogenation on Zirconia‐Supported Copper Nanoparticles: Reaction Intermediates and the Role of the Metal–Support Interface

et al. 2017

View full text Add to dashboard Cite

Methanol synthesis via CO2 hydrogenation is a key step in methanol-based economy. This reaction is catalyzed by supported copper nanoparticles and displays strong support or promoter effects. Zirconia is known to enhance both the methanol production rate and the selectivity. Nevertheless, the origin of this observation and the reaction mechanisms associated with the conversion of CO2 to methanol still remain unknown. Here, we present a mechanistic study of the hydrogenation of CO2 on Cu/ZrO2. Using kinetics, in situ IR and NMR spectroscopies and isotopic labeling strategies, we examined the surface intermediates during CO2 hydrogenation at different pressures. Combined with DFT calculations, we show that formate species is the reaction intermediate and that the zirconia/copper interface is a key for its conversion to methanol.The catalytic hydrogenation of carbon dioxide to methanol is a key process in the sustainable methanol-based economy. [1] While copper-based catalysts are highly active for this transformation, [2] their activity and selectivity strongly depend on the support and/or the promoters. Understanding the copper-support interaction -its effect on the activity and product selectivity -has been a very intensive field of research over the last decade. While the reaction mechanisms and the nature of the active sites on Cu/ZnO systems have been extensively investigated, [3] copper supported on zirconia and related materials also exhibits high activity and selectivity in CO2 hydrogenation to methanol (Eq. 1) by minimizing the formation of CO, a byproduct often resulting from the competitive reverse water-gas shift reaction (Eq. 2). [4] CO2 + 3H2 = CH3OH + H2O ∆rH° (500 K) = -62 kJ.mol -1 (1) CO2 + H2 = CO + H2O ∆rH° (500 K) = +40 kJ.mol -1 (2)Although the copper-zirconia interface was proposed to play a key role in the selective formation of methanol, [4c, 4e-g] the active site and the reaction mechanism, including the role of the interface on methanol selectivity, are still not understood. In fact, mechanistic investigations using Diffuse Reflectance IR Fourier Transform spectroscopy (DRIFTS) led to opposite conclusions: formate is an intermediate in methanol formation [4c, 4d] vs. CO2 is first reduced to CO that is in turn hydrogenated to methanol through a carboxyl intermediate. [4f] Herein, by using a combined experimental and computational approach on realistic models, we investigated the reaction mechanism of CO2 hydrogenation to methanol on a Cu/ZrO2 catalyst. Kinetic investigation, in situ and ex situ spectroscopies -FTIR and NMRtogether with isotopic labeling and computational modelling showed that methanol is a primary product formed by the hydrogenation of formate as a reaction intermediate. First, narrowly dispersed copper nanoparticles supported on monoclinic zirconia were prepared by a molecular approach. [5] Grafting of [Cu(O t Bu)]4 on the surface hydroxyl groups of the support ( Figure S1-S2, Scheme S1) followed by a treatment under H2 at 500 °C for 5 h [6] yields smal...

show abstract

Section: G(itp) = E(i) + Uvib(it) + Urot(it) + Utrans(it) + Pvm mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

CO₂‐to‐Methanol Hydrogenation on Zirconia‐Supported Copper Nanoparticles: Reaction Intermediates and the Role of the Metal–Support Interface

et al. 2017

View full text Add to dashboard Cite

show abstract

“…2. The latter species has been assigned either tribridged 7,25,70,71 , bibridged 29,53,61,63 or simply presumed as multicoordinated OH groups 18,19,23,59 . In this work, the term multicoordinated is generally used to refer to this species.…”

Section: Crystal Structure and Surfacesmentioning

confidence: 99%

“…2200 cm −1 ) can be removed by evacuation at room temperature and CO on Zr 3+ (at ca. 2110 cm −1 ) is slightly more strongly bound to the zirconia surface, yet also possible to evacuate at room temperature 29 . The observed IR band intensities of the (CO) H and (CO) L species with increasing CO pressures are in line with their heats of adsorption: the (CO) H with a higher heat of adsorption has a higher intensity at low pressures and and vice versa at higher pressures 27 .…”

Section: Linear Co Species Formation and Stabilitymentioning

confidence: 99%

Review: monoclinic zirconia, its surface sites and their interaction with carbon monoxide

Kouva

Honkala

Lefferts

et al. 2015

Catal. Sci. Technol.

150

138

View full text Add to dashboard Cite

show abstract

Surface Characterization of Zirconia-Coated Alumina as Support for Pt Particles

Souza¹,

Aranda²,

Perez³

et al. 2001

phys. stat. sol. (a)

View full text Add to dashboard Cite

ZrO 2 /Al 2 O 3 samples were prepared by impregnation of the alumina powder with a solution of zirconium hydroxide in nitric acid, containing ZrO 2 in the range of 1-20 wt%. Platinum was impregnated by incipient wetness technique, using an aqueous solution of H 2 PtCl 6 . The surface coverage of zirconia on alumina, as probed by XPS and ISS, increased up to 10 wt% of ZrO 2 and above this concentration crystallites of zirconia nucleated, which decreases the BET surface area. XRD measurements indicated that the average size of these crystallites was about 1 nm. ISS data of Pt/ZrO 2 and Pt/10%ZrO 2 /Al 2 O 3 catalysts, after reduction at 773 K indicated an increase in the surface population of Zr atoms which are able to catch CO. This interaction was also probed by FTIR spectra of CO adsorbed on Pt/ZrO 2 catalyst, where an intense band at 2130 cm --1 , associated to CO adsorption on Pt-ZrO x interface, was observed.

show abstract

Infrared study of syngas adsorption on zirconia

Cited by 76 publications

References 0 publications

CO₂‐to‐Methanol Hydrogenation on Zirconia‐Supported Copper Nanoparticles: Reaction Intermediates and the Role of the Metal–Support Interface

CO₂‐to‐Methanol Hydrogenation on Zirconia‐Supported Copper Nanoparticles: Reaction Intermediates and the Role of the Metal–Support Interface

Review: monoclinic zirconia, its surface sites and their interaction with carbon monoxide

Surface Characterization of Zirconia-Coated Alumina as Support for Pt Particles

Contact Info

Product

Resources

About

Infrared study of syngas adsorption on zirconia

Cited by 76 publications

References 0 publications

CO2‐to‐Methanol Hydrogenation on Zirconia‐Supported Copper Nanoparticles: Reaction Intermediates and the Role of the Metal–Support Interface

CO2‐to‐Methanol Hydrogenation on Zirconia‐Supported Copper Nanoparticles: Reaction Intermediates and the Role of the Metal–Support Interface

Review: monoclinic zirconia, its surface sites and their interaction with carbon monoxide

Surface Characterization of Zirconia-Coated Alumina as Support for Pt Particles

Contact Info

Product

Resources

About

CO₂‐to‐Methanol Hydrogenation on Zirconia‐Supported Copper Nanoparticles: Reaction Intermediates and the Role of the Metal–Support Interface

CO₂‐to‐Methanol Hydrogenation on Zirconia‐Supported Copper Nanoparticles: Reaction Intermediates and the Role of the Metal–Support Interface