scholarly journals Elucidating the role of H2O in promoting the formation of methacrylic acid during the oxidation of methacrolein over heteropolyacid compounds

2020 ◽  
Author(s):  
SARAYUTE CHANSAI ◽  
Yuki Kato ◽  
Wataru Ninomiya ◽  
Christopher Hardacre
Keyword(s):  
Selective Oxidation ◽  
Mass Spectrometer ◽  
Methacrylic Acid ◽  
In Situ Drifts ◽  
Keggin Type

The involvement of water in the selective oxidation of MAL to MAA over a pure Keggin-type H3PMoO12O40 catalyst was investigated using an in-situ DRIFTS reactor coupled with a mass spectrometer...

scholarly journals Experimental and Theoretical Studies of Sonically Prepared Cu–Y, Cu–USY and Cu–ZSM-5 Catalysts for SCR deNOx

Catalysts ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 824
Author(s):  
Przemysław J. Jodłowski ◽  
Izabela Czekaj ◽  
Patrycja Stachurska ◽  
Łukasz Kuterasiński ◽  
Lucjan Chmielarz ◽  
...  
Keyword(s):  
Ion Exchange ◽  
Ultrasonic Irradiation ◽  
Active Phase ◽  
Spectroscopic Studies ◽  
In Situ Drifts ◽  
Ft Ir ◽  
Diffuse Reflectance Infrared ◽  
Experimental And Theoretical Studies

The objective of our study was to prepare Y-, USY- and ZSM-5-based catalysts by hydrothermal synthesis, followed by copper active-phase deposition by either conventional ion-exchange or ultrasonic irradiation. The resulting materials were characterized by XRD, BET, SEM, TEM, Raman, UV-Vis, monitoring ammonia and nitrogen oxide sorption by FT-IR and Diffuse Reflectance Infrared Fourier Transform Spectroscopy (DRIFTS). XRD data confirmed the purity and structure of the Y/USY or ZSM-5 zeolites. The nitrogen and ammonia sorption results indicated that the materials were highly porous and acidic. The metallic active phase was found in the form of cations in ion-exchanged zeolites and in the form of nanoparticle metal oxides in sonochemically prepared catalysts. The latter showed full activity and high stability in the SCR deNOx reaction. The faujasite-based catalysts were fully active at 200–400 °C, whereas the ZSM-5-based catalysts reached 100% activity at 400–500 °C. Our in situ DRIFTS experiments revealed that Cu–O(NO) and Cu–NH3 were intermediates, also indicating the role of Brønsted sites in the formation of NH4NO3. Furthermore, the results from our experimental in situ spectroscopic studies were compared with DFT models. Overall, our findings suggest two possible mechanisms for the deNOx reaction, depending on the method of catalyst preparation (i.e., conventional ion-exchange vs. ultrasonic irradiation).

Insights into the role of a structural promoter (Ba) in three-way catalyst Pd/CeO2–ZrO2 using in situ DRIFTS

2015 ◽  
Vol 5 (5) ◽  
pp. 2688-2695 ◽  
Author(s):  
Linyan Yang ◽  
Xue Yang ◽  
Siyu Lin ◽  
Renxian Zhou
Keyword(s):  
In Situ Drifts ◽  
Three Way Catalyst

Doping with Ba, especially when the content is 5 wt.%, accelerates the dissociation of NOx and facilitates the formation of intermediates due to the outstanding electron-donating ability of Ba.

Role of water on ozonation of cinnamaldehyde to benzaldehyde under Ca(OH)2 catalysis: A combined in situ DRIFTS and DFT study

2021 ◽  
Vol 569 ◽  
pp. 151071
Author(s):  
Xuan Luo ◽  
Yaru Hou ◽  
Xinling Xie ◽  
Zuzeng Qin ◽  
Hongbing Ji ◽  
...  
Keyword(s):  
Dft Study ◽  
In Situ Drifts

Main aspects of the selective oxidation of isobutane to methacrylic acid catalyzed by Keggin-type polyoxometalates

2001 ◽  
Vol 71 (1-2) ◽  
pp. 97-110 ◽  
Author(s):  
Fabrizio Cavani ◽  
Roberto Mezzogori ◽  
Anne Pigamo ◽  
Ferruccio Trifirò ◽  
Eric Etienne
Keyword(s):  
Selective Oxidation ◽  
Methacrylic Acid ◽  
Keggin Type ◽  
Acid Catalyzed

Elucidating the Role of CO in the NO Storage Mechanism on Pd/SSZ-13 with in Situ DRIFTS

2022 ◽  
Author(s):  
Inhak Song ◽  
Konstantin Khivantsev ◽  
Yong Wang ◽  
János Szanyi
Keyword(s):  
In Situ Drifts ◽  
Storage Mechanism
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