In Situ Spectroscopic Studies of Highly Transparent Nanoparticle Dispersions Enable Assessment of Trithiocarbonate Chain-End Fidelity during RAFT Dispersion Polymerization in Nonpolar Media

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).

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In-situ infrared spectroscopic studies of hydroxyl in amphiboles at high pressure

American Mineralogist ◽

10.2138/am-2016-5465 ◽

2016 ◽

Vol 101 (3) ◽

pp. 706-712 ◽

Cited By ~ 6

Author(s):

Elizabeth C. Thompson ◽

Andrew J. Campbell ◽

Zhenxian Liu

Keyword(s):

High Pressure ◽

Spectroscopic Studies ◽

Infrared Spectroscopic

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Insertion of Phosphenium Ions into a Bicyclo[1.1.0]Tetraphosphabutane Iron Complex

Molecules ◽

10.3390/molecules26133920 ◽

2021 ◽

Vol 26 (13) ◽

pp. 3920

Author(s):

Martin Weber ◽

Gábor Balázs ◽

Alexander V. Virovets ◽

Eugenia Peresypkina ◽

Manfred Scheer

Keyword(s):

Diffraction Analysis ◽

Room Temperature ◽

31P Nmr ◽

Spectroscopic Studies ◽

Iron Complex ◽

The Novel ◽

X Ray Diffraction ◽

X Ray ◽

Phosphenium Ions

By reacting [{Cp‴Fe(CO)2}2(µ,η1:1-P4)] (1) with in situ generated phosphenium ions [Ph2P][A] ([A]− = [OTf]− = [O3SCF3]−, [PF6]−), a mixture of two main products of the composition [{Cp‴Fe(CO)2}2(µ,η1:1-P5(C6H5)2)][PF6] (2a and 3a) could be identified by extensive 31P NMR spectroscopic studies at 193 K. Compound 3a was also characterized by X-ray diffraction analysis, showing the rarely observed bicyclo[2.1.0]pentaphosphapentane unit. At room temperature, the novel compound [{Cp‴Fe}(µ,η4:1-P5Ph2){Cp‴(CO)2Fe}][PF6] (4) is formed by decarbonylation. Reacting 1 with in situ generated diphenyl arsenium ions gives short-lived intermediates at 193 K which disproportionate at room temperature into tetraphenyldiarsine and [{Cp‴Fe(CO)2}4(µ4,η1:1:1:1-P8)][OTf]2 (5) containing a tetracyclo[3.3.0.02,7.03,6]octaphosphaoctane ligand.

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Toward a mechanistic understanding of electrocatalytic nanocarbon

Nature Communications ◽

10.1038/s41467-021-23486-1 ◽

2021 ◽

Vol 12 (1) ◽

Author(s):

Erik J. Askins ◽

Marija R. Zoric ◽

Matthew Li ◽

Zhengtang Luo ◽

Khalil Amine ◽

...

Keyword(s):

Spectroscopic Studies ◽

Synthetic Methods ◽

Computational Studies ◽

Molecular Models ◽

Chemical Production ◽

True Nature ◽

Catalytic Mechanisms ◽

Mechanistic Understanding ◽

Further Development

AbstractElectrocatalytic nanocarbon (EN) is a class of material receiving intense interest as a potential replacement for expensive, metal-based electrocatalysts for energy conversion and chemical production applications. The further development of EN will require an intricate knowledge of its catalytic behaviors, however, the true nature of their electrocatalytic activity remains elusive. This review highlights work that contributed valuable knowledge in the elucidation of EN catalytic mechanisms. Experimental evidence from spectroscopic studies and well-defined molecular models, along with the survey of computational studies, is summarized to document our current mechanistic understanding of EN-catalyzed oxygen, carbon dioxide and nitrogen electrochemistry. We hope this review will inspire future development of synthetic methods and in situ spectroscopic tools to make and study well-defined EN structures.

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