Application of Infrared Spectroscopy in Catalysis: Impacts on Catalysts’ Selectivity

Concepción, Patricia

doi:10.5772/intechopen.80524

Cited by 5 publications

(2 citation statements)

References 78 publications

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“…Furthermore, the interaction between ammonia Lewis's base and the Brønsted and Lewis sites of the catalyst was evaluated through the IR spectra of the TCA/H-zeolite catalyst in Figure 3. The interaction of ammonia with the Lewis and Brønsted active sites was designated by the vibrations at wavenumbers of 1,450 cm −1 and 1,550 -1,640 cm −1 , respectively [30]. The surface porosity of a catalyst is an important property of the catalyst in supporting the catalytic performance.…”

Section: The Characteristics Of Tca/h-zeolite Catalystmentioning

confidence: 99%

The Catalytic Activity of TCA-Modified Indonesian Natural Zeolite During the Esterification of Sengon Wood Bio-Oil

et al. 2022

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The bio-oil produced from the pyrolysis of biomass is highly corrosive due to the high content of organic acids. These organic acids could be removed through an appropriate upgrading process, i.e., esterification using alcohols to form less polar esters. In this study, the bio-oil used as the feedstock in the esterification was produced from the pyrolysis of Sengon wood with a particle size of 297 µm at 600 °C. The esterification was performed at 70 °C in the presence of a trichloro acetic acid (TCA)-modified Indonesian H-zeolite catalyst with various weight ratios of bio-oil-to-methanol and reaction times under a constant stirring rate of 500 rpm. The esterification progress was indicated by the decrease in the total acid number of the bio-oil after esterification. No significant coke formation (< 0.05 wt%) was observed indicating that the suppression of repolymerisation could be achieved. This study showed that the esterification underwent in a fast rate, indicated by the decrease in the total acid number of the bio-oil by 47.85 % only over a 15-min esterification. Compared to the uncatalysed esterification, the TCA/zeolite-catalysed esterification showed a higher decrease in the total acid number of the bio-oil up to 65.83 %, due to the conversion of the carboxylic acids to esters. HIGHLIGHTS The TCA-modified Indonesian natural zeolite catalyst has been successfully prepared The presence of the TCA/Indonesian natural zeolite during the esterification of bio-oil produced from the pyrolysis of Sengon wood could greatly suppress the severe repolymerisation leading to coke formation The TCA/Indonesian natural zeolite-catalysed esterification of Sengon bio-oil underwent in a fast rate The TCA/Indonesian natural zeolite catalyst showed a good performance in this study in comparison with the uncatalysed esterification GRAPHICAL ABSTRACT

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Section: The Characteristics Of Tca/h-zeolite Catalystmentioning

confidence: 99%

The Catalytic Activity of TCA-Modified Indonesian Natural Zeolite During the Esterification of Sengon Wood Bio-Oil

et al. 2022

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“…A espectroscopia de infravermelho na catálise é aplicada na análise do mecanismo de reação, pois, é possível acompanhar "in situ" a evolução das espécies intermediárias ao longo do tempo de reação (CONCEPCIÓN, 2018).…”

Section: Métodos De Caracterizaçãounclassified

Preparação e caracterização de eletrocatalisadores à base de PtBi/C, PdBi/C e PtPdBi/C para a oxidação do etanol em meio alcalino em células a combustível

Lima¹

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SANTOS LIMA, Fabiana dos. Preparação e caracterização de eletrocatalisadores à base de PtBi/C, PdBi/C e PtPdBi/C para a oxidação do etanol em meio alcalino em células a combustível. 2021. 109 p. Tese (Doutorado em Tecnologia Nuclear) Instituto de Pesquisas Energéticas e Nucleares -IPEN-CNEN/SP. São Paulo.Environmental pollution and the high costs associated with the use of fossil fuels have motivated the development of alternative energy sources. In this sense, fuel cells are a promising alternative, as they enable the use of fuels from renewable sources, such as ethanol, which has a well-developed production system in Brazil.However, in the incomplete reaction of ethanol oxidation there is formation of intermediate species and by-products, which are adsorbed on the surface of the electrocatalyst causing its deactivation and consequent reduction of energy efficiency of the system, a limiting factor which can be minimized by the addition of metals such as bismuth to platinum and palladium. Therefore, the electrocatalysts PtBi/C (95:5), PdBi/C (95:5) e PtPdBi/C (90:5:5), were synthesized through reduction by sodium borohydride process. The electrocatalytic activity was analyzed through cyclic voltametry and chronoamperometry in alkaline medium with three different concentrations of ethanol (0.5, 1.0 and 2.0 mol.L -1 ) and direct ethanol unit cell tests. The electrocatalysts showed an average particle size between 5 and 8 nm, and the XPS spectra showed that the presence of bismuth did not cause a significant change in the binding energy values, which suggests that there was no formation of intermetallic compounds, in agreement with the data obtained from XRD, which did not indicate the formation of alloys, only the presence of peaks characteristic of the metals Pt and Pd. The results of ATR-FTIR show that the addition of Bi suppresses carbonate production and increases acetate yield independent of ethanol concentration, indicating the preferential occurrence of partial oxidation of ethanol. As for the electrocatalytic performance, the best results in current density were obtained with PtBi/C (95:5), which was about four times higher than Pt/C. Therefore, the results suggest that the association of bismuth with platinum is extremely beneficial and its high electrocatalytic activity can be attributed to the synergy between its constituents, considering the bifunctional mechanism.

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Infrared (IR) Spectroscopy

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2023

Springer Handbooks

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Application of Infrared Spectroscopy in Catalysis: Impacts on Catalysts’ Selectivity

Cited by 5 publications

References 78 publications

The Catalytic Activity of TCA-Modified Indonesian Natural Zeolite During the Esterification of Sengon Wood Bio-Oil

The Catalytic Activity of TCA-Modified Indonesian Natural Zeolite During the Esterification of Sengon Wood Bio-Oil

Preparação e caracterização de eletrocatalisadores à base de PtBi/C, PdBi/C e PtPdBi/C para a oxidação do etanol em meio alcalino em células a combustível

Infrared (IR) Spectroscopy

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