Ethylene trapping of palladium-impregnated zeolites for cold-start emission control

Ryu, Taekyung; Jeong, Jaehoon; Byun, Sang Woo; Kweon, Sungjoon; Park, Jiseok; Bae, Wo Bin; Kim, Do Yeong; Kim, Young Jin; Park, Min Bum; Kang, Sung Bong

doi:10.1016/j.cej.2022.136197

Cited by 18 publications

(12 citation statements)

References 44 publications

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“…This peak could be assigned to the adsorption of NH 3 on large PdO particles. 37,39 The absence of this peak at 1 and 2 wt % PdO/ZSM-5 samples is due to the uniform dispersion of PdO. However, at higher Pd loadings (3−5 wt %), the Pd species form larger PdO particles, as confirmed by XRD.…”

Section: ■ Results and Discussionmentioning

confidence: 83%

“…26−32 The presence of Pd + and Pd 0 may be due to partially reduced Pd species under a CO atmosphere. 31,37 These results suggest that PdO/ZSM-5 significantly enhances the adsorption capacity for CO compared to ZSM-5, promoting the activation of CO, which may contribute to the carbonylation process. We further examined the CO adsorption capacity of PdO species by CO-TPD experiments.…”

Section: ■ Results and Discussionmentioning

confidence: 84%

“…However, the intensity of the NH 3 desorption peak at the strong acid site around 360–390 °C did not show a significant change. This is attributed to the appearance of Pd 2+ after Pd immersion treatment of the zeolite, ,,, which generates a NH 3 desorption peak around 360–390 °C, overlapping with the position of the strong acid sites of zeolite. A new sharp desorption peak appeared around 270 °C when the Pd loading increased to 3 wt %, and the intensity of this peak increased with a further increase in Pd loading (as depicted in Figure ).…”

Section: Resultsmentioning

confidence: 99%

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Boosting the Production of Glycolic Acid from Formaldehyde Carbonylation via the Bifunctional PdO/ZSM-5 Catalyst

Cao,

Zhang,

Wang

et al. 2023

Ind. Eng. Chem. Res.

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The carbonylation of formaldehyde offers a promising, cost-effective, and environmentally friendly method for synthesizing glycolic acid, a crucial monomer in biodegradable plastics. This study highlights the development and optimization of a bifunctional PdO/ZSM-5 zeolite catalyst for this process. Investigations via various spectroscopic techniques reveal that Pd species, predominantly in the form of PdO, enhance the CO activation, thereby boosting the formaldehyde carbonylation reaction rate significantly. The optimal catalytic performance was observed with a Pd-loading of 2 wt %. Notably, excessive Pd loading was found to impede the catalytic performance by overoccupying acid sites, thereby reducing its capacity to activate formaldehyde. The concurrent activation of formaldehyde and CO at the Brønsted acid site and the PdO site, respectively, through a Langmuir–Hinshelwood mechanism is key to the enhanced catalytic performance. These findings underscore the importance of CO activation in improving the formaldehyde carbonylation process, offering vital insights for catalyst optimization.

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Section: ■ Results and Discussionmentioning

confidence: 83%

Section: ■ Results and Discussionmentioning

confidence: 84%

Section: Resultsmentioning

confidence: 99%

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Boosting the Production of Glycolic Acid from Formaldehyde Carbonylation via the Bifunctional PdO/ZSM-5 Catalyst

Cao,

Zhang,

Wang

et al. 2023

Ind. Eng. Chem. Res.

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“…Hydrocarbons, which are always present in vehicle exhaust, also impact the NO adsorption over Pd/SSZ-13 [33,[36][37][38][39][40]. In recent decades, it has been found that zeolites have the ability to store HCs at temperatures below 200 • C, while the presence of H 2 O was found to be detrimental for HC storage [7,41].…”

Section: Introductionmentioning

confidence: 99%

Mechanistic insight in the propylene derived distinct NO uptake and release behaviors on Pd/SSZ-13 for low-temperature NO adsorption

Zhao

Chen

Hill

et al. 2023

Chemical Engineering Journal

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“…Therefore, traditional TPR characterization can only provide some qualitative or semi-quantitative information, such as the ratio of hydrogen consumption in different reduction stages, rather than the exact number of hydrogen molecules consumed. , On the other hand, the TPR reaction of H 2 with the catalyst generates H 2 O molecules, which significantly affects the detection of TCD to hydrogen. − Hence, it is generally necessary to install a cold trap system in the instrument to remove the produced H 2 O molecules from the gas stream prior to the detection. − The use of cold traps brings complexity to the instrument construction and experimental operation and also increases the distance between the detector and the sample, which may lead to weak and delayed ex situ detection signals. Further, some highly active catalysts with ultra-low TPR temperatures have drawn much attention to achieve a green and sustainable development. − However, it is difficult for the existing TPR instruments to initiate TPR measurements from below the freezing point. , Therefore, developing an in situ H 2 -TPR measurement method with high sensitivity and wide operating temperature range is of great significance to meet the requirements of high-performance catalyst characterization.…”

Section: Introductionmentioning

confidence: 99%

In Situ Hydrogen Temperature-Programmed Reduction Technology Based on the Integrated Microcantilever for Metal Oxide Catalyst Analysis

Zhou

et al. 2022

Anal. Chem.

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Hydrogen temperature-programmed reduction (H 2 -TPR) technique is significant for catalyst characterization. The available instruments typically measure the H 2 consumption using a thermal conductivity detector (TCD), which is strongly affected by the produced H 2 O molecules. Herein, we demonstrate an in situ TPR technology based on a silicon microcantilever, in which resonance exciting/detecting components and heating electrodes for catalyst samples are integrated. The microcantilever-based H 2 -TPR technology requires only 20 ng of the sample and eliminates the requirements of TCD and cold trap. During the self-heating up to 1000 °C, reduction-induced mass change of the sample can be in situ measured with picogram-level resolution. Compared with the available instruments, the microcantilever-based H 2 -TPR technology directly and in situ measures the mass change of the sample, without using H 2 consumption to indirectly represent the reduction process, thus significantly improving the characterization accuracy. The microcantilever-based TPR technology has been successfully used to characterize various metal oxide catalysts with satisfactory accuracy. The in situ TPR results of the three CuO samples with different grain sizes clearly distinguish their different maximum temperatures, revealing the size effect of the catalyst. The microcantilever can also be placed in a low-temperature test chamber, enabling successful frozen H 2 -TPR analysis of catalysts with low reduction temperatures, such as PdO. Featuring simplified operation but high detecting accuracy, the microcantilever-based in situ H 2 -TPR technology is promising in the analytic applications of advanced catalysts.

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Ethylene trapping of palladium-impregnated zeolites for cold-start emission control

Cited by 18 publications

References 44 publications

Boosting the Production of Glycolic Acid from Formaldehyde Carbonylation via the Bifunctional PdO/ZSM-5 Catalyst

Boosting the Production of Glycolic Acid from Formaldehyde Carbonylation via the Bifunctional PdO/ZSM-5 Catalyst

Mechanistic insight in the propylene derived distinct NO uptake and release behaviors on Pd/SSZ-13 for low-temperature NO adsorption

In Situ Hydrogen Temperature-Programmed Reduction Technology Based on the Integrated Microcantilever for Metal Oxide Catalyst Analysis

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