Insights into the Nature of Formate Species in the Decomposition and Reaction of Methanol over Cerium Oxide Surfaces: A Combined Infrared Spectroscopy and Density Functional Theory Study

Lustemberg, Pablo G.; Bosco, Marta V.; Bonivardi, Adrian Lionel; Busnengo, H. F.; Ganduglia‐Pirovano, M. V.

doi:10.1021/acs.jpcc.5b05070

Cited by 52 publications

(57 citation statements)

References 70 publications

(114 reference statements)

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“…The previously calculated barriers for the formation of acetaldehyde through HC scission from the LD and SU ethoxy species on the CeO 2 (111) surface [48], provide support to our proposal, since a larger energy barrier was found for the formation of acetaldehyde through -HC scission in the case of the LD species (2.08 eV) as compared to the barrier for the process through -HC scission in the case of the SU ethoxy species (1.11 eV). It is important to note that the here reported theoretical calculations predict OH groups to have a decisive impact on the adsorbed ethoxy species (see Supporting Information), similar as previously reported for formate on ceria [49].…”

Section: Adsorption Of Ethanol On Ceo 2 and Cegao Xsupporting

confidence: 86%

Controlled selectivity for ethanol steam reforming reaction over doped CeO2 surfaces: The role of gallium

Vecchietti

Lustemberg

Fornero

et al. 2020

Applied Catalysis B: Environmental

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The ethanol steam reforming reaction, together with the adsorption and decomposition of ethanol was studied on CeO 2 and gallium-doped ceria (CeGaO x) by a combined experimental and theoretical approach using infrared spectroscopy (IR), mass spectrometry (MS) and density functional theory (DFT) calculations. At 100°C, different types of monodentate ethoxy species were identified as standing-up (SU) on Ce 4+ and lying-down (LD) on Ce 4+ and Ga 3+ , with the alkyl chain more perpendicular or parallel to the surface, respectively. It is suggested that the incorporation of Ga into the ceria lattice changes the decomposition pathway of LD species, which converts to acetate instead of ethylene, attributed to the increased lattice oxygen lability in the CeOGa interface upon doping and the propensity to form GaH surface species. Under ethanol steam reforming conditions, Ga doping of ceriabased materials has a drastic effect by improving the H 2 :CO 2 ratio, changing the product distribution and reducing coke formation.

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Section: Adsorption Of Ethanol On Ceo 2 and Cegao Xsupporting

confidence: 86%

Controlled selectivity for ethanol steam reforming reaction over doped CeO2 surfaces: The role of gallium

Vecchietti

Lustemberg

Fornero

et al. 2020

Applied Catalysis B: Environmental

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“…After methanol adsorption (CH 3 OH/He, 100 °C) on the reference ceria sample (Fig. 4a, b), the spectrum shows bands at 2942, 2911, 2888 and 2840 cm − 1 (ν C-H), attributed to the stretching vibrations of the surface methoxy -OCH 3 groups [50][51][52][53]. At the lower frequency range, their bending equivalents are the bands at 1463, 1371, 1355, 1103 and 1056 cm − 1 .…”

Section: Methanol Adsorptionmentioning

confidence: 99%

Towards Methane Combustion Mechanism on Metal Oxides Supported Catalysts: Ceria Supported Palladium Catalysts

et al. 2019

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The application of methane as a fuel in the automotive industry shows an increasing tendency, but its release into the atmosphere is detrimental due to its very high greenhouse effect. For this reason, new solutions for cleaning systems of exhaust gas from methane engines are in demand. This study focuses on thorough characterisation of active centres, structure-activity relationships, and reaction steps on palladium ceria supported catalysts of different loading, using the in situ FTIR method with different surface probe molecules. The results show substantial activity of low loading Pd/CeO 2 catalyst, correlated with its high dispersion. Three types of active centres were found on the catalyst surface: acidic and redox on both the ceria and palladium oxide surfaces, and basic ones on the palladium oxide. The reaction on the Pd/CeO 2 catalyst was shown to proceed via the formation of monodentates, which were a stable reaction intermediate in the temperature range between 150 and 250 °C. The assignment of the intermediates was supported by the in situ FTIR sorption experiments with CO, CH 4 used as probe molecules.

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“…52 As for the WGS reaction, it is reported that the high oxygen storage capacity is beneficial to the catalyst activity as the oxygen could operate in a redox mode. [53][54][55][56] Table 2 shows the quantitative analysis of oxygen species in the reduced catalysts. The amount of lattice oxygen per surface area increases with an increasing amount of CeO 2 because the CeO 2 is known to have an oxygen storage capacity.…”

Section: Reduction Profile (Tpr) Of Fresh Catalystsmentioning

confidence: 99%

Sulfur resistant La_xCe_1−xNi_0.5Cu_0.5O₃ catalysts for an ultra-high temperature water gas shift reaction

Oemar

Bian

Hidajat

et al. 2016

Catal. Sci. Technol.

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A series of La x Ce 1−x Ni 0.5 Cu 0.5 O 3 catalysts was synthesized to study the effect of Ce substitution for La. XRD results show that only a small amount of Ce (10%) is allowable to substitute La to maintain the perovskite structure. The La 0.9 Ce 0.1 Ni 0.5 Cu 0.5 O 3 catalyst has the smallest metal particle size and the highest oxygen mobility among all tested catalysts as observed from the XRD, TPD-O 2 , and XPS results of reduced catalysts. These two factors are very important in achieving the highest catalytic activity of the La 0.9 Ce 0.1 Ni 0.5 Cu 0.5 O 3 catalyst in a water gas shift reaction at 450-650°C. In the presence of H 2 S, the catalytic activity at lower temperature was suppressed due to the formation of stable SO 4 2− species on the metal. However, since the amounts of surface oxygen species and adsorbed H 2 S are much lower at high temperature, the formation of SO 4 2− species is not observed, resulting in higher catalytic activity. The presence of H 2 S at high temperature enhances the formation of formate species, which can decompose to produce methane as the side product of the water gas shift reaction. IntroductionThe Water Gas Shift (WGS) reaction is one of the key reactions for hydrogen production in industry. The reaction is favorable at a low reaction temperature due to exothermicity. However, the reaction rate is lower at lower temperatures. Hence, the WGS reaction is industrially performed in two stages, i.e. high temperature WGS at 350-450°C to increase the reaction rate using an Fe-Cr catalyst, followed by low temperature WGS at 200-250°C to convert the remaining CO in the system using a Cu-Zn catalyst. With current growing interest in hydrogen production via biomass gasification technology which produces sulfur containing syngas, it is important to develop a new catalyst having high activity and stability not only at low (200-250°C) and high temperature (350-450°C) WGS reactions but also at ultra high temperatures (500-650°C) in the presence of a wide range of sulfur concentration. It is understood that biomass gasification is usually performed at high temperatures of 700-900°C. The syngas produced from the biomass gasification has a temperature of 700°C while the conventional WGS reaction requires lower reaction temperatures (200-450°C ). Hence, the syngas needs cooling for the reaction to take place, which means energy loss. The ultra high temperature WGS reaction can minimize the energy loss due to cooling of syngas. The consequences of having a sulphur resistant WGS catalyst is that the downstream hydrogen separation process should have sulphur resistant properties as well. Hence, there is growing interest in sulphur resistant H 2 separation membranes. 1 Various types of sulfur-resistant catalysts have been reported in the literature, such as W-based catalysts, 2,3 Mobased catalysts 4-7 lanthanide oxysulfide La 2 O 2 S, 8,9 noble metal catalysts (Rh,10,(11)(12)(13)), and phosphide catalysts. 14 Sulphided CoMo catalysts in promoted and unpromoted systems have been extensively...

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Insights into the Nature of Formate Species in the Decomposition and Reaction of Methanol over Cerium Oxide Surfaces: A Combined Infrared Spectroscopy and Density Functional Theory Study

Cited by 52 publications

References 70 publications

Controlled selectivity for ethanol steam reforming reaction over doped CeO2 surfaces: The role of gallium

Controlled selectivity for ethanol steam reforming reaction over doped CeO2 surfaces: The role of gallium

Towards Methane Combustion Mechanism on Metal Oxides Supported Catalysts: Ceria Supported Palladium Catalysts

Sulfur resistant La_xCe_1−xNi_0.5Cu_0.5O₃ catalysts for an ultra-high temperature water gas shift reaction

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Insights into the Nature of Formate Species in the Decomposition and Reaction of Methanol over Cerium Oxide Surfaces: A Combined Infrared Spectroscopy and Density Functional Theory Study

Cited by 52 publications

References 70 publications

Controlled selectivity for ethanol steam reforming reaction over doped CeO2 surfaces: The role of gallium

Controlled selectivity for ethanol steam reforming reaction over doped CeO2 surfaces: The role of gallium

Towards Methane Combustion Mechanism on Metal Oxides Supported Catalysts: Ceria Supported Palladium Catalysts

Sulfur resistant LaxCe1−xNi0.5Cu0.5O3 catalysts for an ultra-high temperature water gas shift reaction

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Sulfur resistant La_xCe_1−xNi_0.5Cu_0.5O₃ catalysts for an ultra-high temperature water gas shift reaction