FTIR Study of the Adsorption of Methanol on Clean and Ca-Promoted Pd/SiO2 Catalysts

Cabilla, Griselda C.; Bonivardi, Adrian Lionel; Baltanás, Miguel Angel

doi:10.1006/jcat.2001.3253

Cited by 48 publications

(47 citation statements)

References 39 publications

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“…1). Several bands appeared in the CH stretching region (Table 1), which are identical to the ones obtained after exposing pure SiO 2 to methanol [17]. The most intense signals, at 2960 and 2860 cm À1 , are frequently assigned to the symmetric and asymmetric CH stretching of adsorbed methoxy, n as (CH 3 ) and n s (CH 3 ), respectively.…”

Section: Decomposition Of Methanol On Pd/siomentioning

confidence: 74%

“…2 shows the thermal evolution of the intensity of the most relevant IR bands of the surface species. The concentration of stable methoxy species steadily decreased with heating, but they still remained on the surface of the silica even at 723 K [17]. Concurrently, the concentrations of HCO and CO S also decreased on the palladium surface, but neither CO L nor CO B were present from 448 K onward.…”

Section: Decomposition Of Methanol On Pd/siomentioning

confidence: 93%

“…CO + 2H 2 , proceeds fast on the palladium surface, even at sub-ambient temperature [17,22]. Moreover, IR signals attributed to CH 3 OH-Pd and CH 3 O-Pd were observed by exposing Pd/SiO 2 to methanol even at 213 K [17].…”

Section: Decomposition Of Methanol On Pd/siomentioning

confidence: 97%

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Mechanism of the decomposition of adsorbed methanol over a Pd/α,β-Ga2O3 catalyst

Collins

Baltanás

Bonivardi

2005

Applied Catalysis A: General

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Section: Decomposition Of Methanol On Pd/siomentioning

confidence: 74%

Section: Decomposition Of Methanol On Pd/siomentioning

confidence: 93%

See 1 more Smart Citation

Mechanism of the decomposition of adsorbed methanol over a Pd/α,β-Ga2O3 catalyst

Collins

Baltanás

Bonivardi

2005

Applied Catalysis A: General

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“…Subsequently, Pd catalysts supported on ZnO [15], Al 2 O 3 [16], La 2 O 3 [17], CeO 2 [18] and Nd 2 O 5 [17] were prepared and used in the selective hydrogenation of CO 2 into CH 3 OH. It well known that alkali and alkaline earth metals are effective promoters for enhancing the CH 3 OH synthesis activity of Pd/SiO 2 [19]. Thus, on the basis of the above experimental facts, Pd is found to be a good catalyst for CO 2 hydrogenation.…”

Section: Introductionmentioning

confidence: 88%

Pd-Promoter/MCM-41: A Highly Effective Bifunctional Catalyst for Conversion of Carbon Dioxide

et al. 2015

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As on today, the conversion of carbon dioxide into methanol has been considered as one of the top research priorities all over the world. In this work, a series of supported Pd catalysts was prepared by impregnation method with using Pd (NO 3 ) 2 as a precursor and employed as a catalyst in the synthesis of methanol from carbon dioxide. In this process, the surface area and pore volume of support affected the Pd dispersity and catalytic activity of supported Pd catalyst. At the same time, the catalytic performance was enhanced when the alkaline earth oxide CaO was used as a promoter, and the effect of the loading of Pd and promoter was investigated. The 12.1 % of CO 2 conversion and the 65.2 % of selectivity for methanol were obtained over the catalyst Pd 6 Ca 3 /MCM-41 at 9 h onstream. Graphical AbstractPd CaO 3H 2 CO 2

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“…Formyl species have also been found at this temperature, but they promptly disappear when the catalyst is heated and the formation of CO and H 2 prevails. [13,15] Methyl formate can form through the condensation of adsorbed methoxides with HCHO to form methoxymethanol intermediates (CH 3 OCH 2 OH) that then dehydrogenate to methyl formate. [16] The esterification of formic acid (HCOOH) intermediates formed by HCHO oxidation is also possible but the high selectivities to methyl formate reported here indicate that fast reactions through condensation of HCHO to methyl formate occur.…”

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confidence: 99%

Low Temperature‐High Selectivity Process over Supported Pd Nanoparticles in Partial Oxidation of Methanol

2011

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The most important challenge in gas phase heterogeneous catalysis is to reach high selectivity in a desired process. Many efforts are made at present to improve selectivity in high temperature reactions (> 350 8C); however, under high temperature, it seems very difficult to reach a very high (about 100 %) selectivity. The main reason for this is probably the difficulty (and maybe the impossibility) to separate the reactivity of the selective and non-selective active sites of the catalyst. In general, both sites form a part of the same structure of the active phase and they are located in a near proximity. Then, under the reaction conditions, the dynamic phenomena (oxidation and reduction rates, acid and base properties, restructuration of active sites and phases, formation of new phases, migration and reactivity of chemical species, formation of intermediates etc.) on which selectivity depends, are simultaneously involved and concern selective and non-selective sites. For these reasons, it could be stated that probably the only way to get high selectivity in gas phase heterogeneous catalysis is to work under "low temperature conditions".It is well known that the nanosize of the catalytic particles could play an important role in the design of new catalytic processes. The decrease in size increases the catalytic activity. The small size can provide a large amount of surface atoms, which results in the high catalytic activity per unit amount of metal. Because surface atoms tend to be coordinatively unsaturated, there is a large energy associated with this surface. The smaller the nanoparticles, the larger the contribution made by the surface energy to the overall energy of the system will be. On the other hand, when the particles are too small, quantum effects prevail over the classical size effect giving the particles new and unexpected properties. Therefore, it is absolutely necessary to use synthesis techniques capable of producing nanoparticles of the catalytic active phases with a tailored-size distribution. In contrast, the partial oxidation of methanol (POMeOH) is usually performed at a relatively high temperature (above 250 8C), but the selectivity of the reaction is very low. Several reaction products, such as formaldehyde and dimethoxymethane (on the redox sites) and dimethyl ether and carbon oxides (on the basic and acidic sites), can be obtained. [1][2][3] We report that methyl formate (MF) could be produced directly from methanol under the oxidation reaction conditions, with a very high selectivity, in a one step reaction performed on catalysts formed by Pd nanoparticles supported on TiO 2 at low temperature and under atmospheric pressure.The Pd/TiO 2 catalysts were prepared by using the water-inoil microemulsion method (Scheme 1). This method is interesting because the chemical reduction and then the precipitation from solutions is a highly versatile and simple method to perform the synthesis of small supported particles. It is well recognized that the size control of nanoparticles can be achieved by ...

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FTIR Study of the Adsorption of Methanol on Clean and Ca-Promoted Pd/SiO2 Catalysts

Cited by 48 publications

References 39 publications

Mechanism of the decomposition of adsorbed methanol over a Pd/α,β-Ga2O3 catalyst

Mechanism of the decomposition of adsorbed methanol over a Pd/α,β-Ga2O3 catalyst

Pd-Promoter/MCM-41: A Highly Effective Bifunctional Catalyst for Conversion of Carbon Dioxide

Low Temperature‐High Selectivity Process over Supported Pd Nanoparticles in Partial Oxidation of Methanol

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