Heterojunction WO<sub>3</sub>–BiVO<sub>4</sub> Photoanodes for TEMPO-Mediated Benzyl Alcohol Dehydrogenation in Organic Media

McMillan, Nelli Klinova; Wortley, Jacob; Nguyen, Khanh; Lopez, Diego A.; Leem, Gyu; Sherman, Benjamin D.

doi:10.1021/acsaenm.3c00549

“…Meanwhile, the highly reproducible and stable transient photocurrent responses of Bi–Mo/CN-2 in 5 photoperiods under continuous switching visible light irradiation indicate the prolonged lifetime on Bi–Mo/CN-2. In addition, EIS was also used to test the separation and transfer efficiencies of photogenerated electron–hole pairs . In EIS analysis, the size of the arc radius reflects the charge separation and transfer efficiency, and the smallest arc radius of Bi–Mo/CN-2 indicates that the synthesized Bi–Mo/CN-2 has the smallest charge transfer impedance (Figure b), which effectively suppresses the recombination of photogenerated electron–hole pairs.…”

Section: Resultsmentioning

confidence: 99%

Highly Selective Photooxidation of Benzyl Alcohol to Benzaldehyde by Bi–Mo/g-C₃N₄ in Aqueous Solution

Sheng,

He,

Cao

et al. 2024

Ind. Eng. Chem. Res.

1

0

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Although photooxidation of benzyl alcohol to benzaldehyde in aqueous solution is an important chemical process, its selectivity cannot be readily controlled due to the overoxidation of benzaldehyde. In this study, a series of Bi–Mo/CN photocatalysts are synthesized, and their reactivity in photooxidation of benzyl alcohol under visible light is compared. Bi–Mo/CN-2 exhibits high photocatalytic reactivity in the conversion of benzyl alcohol (51%) with a high selectivity toward benzaldehyde of 99.9%. In this process, the formed Bi–OO• and Bi–OOH selectively oxidize benzyl alcohol to benzaldehyde via the H-abstraction pathway after O2 is photoreduced on Bi–Mo/CN, accompanied by the formation of H2O2. Meanwhile, the doped Mo utilizes the produced H2O2 or Bi–OOH to produce Mo–O2 peroxo, which not only contributes to the selective oxidation of benzyl alcohol to benzaldehyde but also effectively prevents overoxidation of benzaldehyde. This work provides new insight into designing novel photocatalysts for selective oxidation of organic substrates.

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Programmable C−N Bond Formation through Radical‐Mediated Chemistry in Plasma‐Microdroplet Fusion

Grooms,

Huttner,

Stockwell

et al. 2024

Angewandte Chemie

0

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Non‐thermal plasma discharge produced in the wake of charged microdroplets is found to facilitate catalyst‐free radical mediated hydrazine cross‐coupling reactions without the use of external light source, heat, precious metal complex, or trapping agents. A plasma‐microdroplet fusion platform is utilized for introduction of hydrazine reagent that undergoes homolytic cleavage forming radical intermediate species. The non‐thermal plasma discharge that causes the cleavage originates from a chemically etched silica capillary. The coupling of the radical intermediates gives various products. Plasma‐microdroplet fusion occurs online in a programmable reaction platform allowing direct process optimization and product validation via mass spectrometry. The platform is applied herein with a variety of hydrazine substrates, enabling i) self‐coupling to form secondary amines with identical N‐substitutions, ii) cross‐coupling to afford secondary amine with different N‐substituents, iii) cross‐coupling followed by in‐situ dehydrogenation to give the corresponding aryl‐aldimines with two unique N‐substitutions, and iv) cascade heterocyclic carbazole derivatives formation. These unique reactions were made possible in the charged microdroplet environment through our ability to program conditions such as reagent concentration (i.e., flowrate), microdroplet reactivity (i.e., presence or absence of plasma), and reaction timescale (i.e., operational mode source). The selected program is implemented in a co‐axial spray format.

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Programmable C−N Bond Formation through Radical‐Mediated Chemistry in Plasma‐Microdroplet Fusion

Grooms,

Huttner,

Stockwell

et al. 2024

Angew Chem Int Ed

0

View full text Add to dashboard Cite

Non‐thermal plasma discharge produced in the wake of charged microdroplets is found to facilitate catalyst‐free radical mediated hydrazine cross‐coupling reactions without the use of external light source, heat, precious metal complex, or trapping agents. A plasma‐microdroplet fusion platform is utilized for introduction of hydrazine reagent that undergoes homolytic cleavage forming radical intermediate species. The non‐thermal plasma discharge that causes the cleavage originates from a chemically etched silica capillary. The coupling of the radical intermediates gives various products. Plasma‐microdroplet fusion occurs online in a programmable reaction platform allowing direct process optimization and product validation via mass spectrometry. The platform is applied herein with a variety of hydrazine substrates, enabling i) self‐coupling to form secondary amines with identical N‐substitutions, ii) cross‐coupling to afford secondary amine with different N‐substituents, iii) cross‐coupling followed by in‐situ dehydrogenation to give the corresponding aryl‐aldimines with two unique N‐substitutions, and iv) cascade heterocyclic carbazole derivatives formation. These unique reactions were made possible in the charged microdroplet environment through our ability to program conditions such as reagent concentration (i.e., flowrate), microdroplet reactivity (i.e., presence or absence of plasma), and reaction timescale (i.e., operational mode source). The selected program is implemented in a co‐axial spray format.

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Heterojunction WO₃–BiVO₄ Photoanodes for TEMPO-Mediated Benzyl Alcohol Dehydrogenation in Organic Media

Cited by 3 publications

References 42 publications

Highly Selective Photooxidation of Benzyl Alcohol to Benzaldehyde by Bi–Mo/g-C₃N₄ in Aqueous Solution

Highly Selective Photooxidation of Benzyl Alcohol to Benzaldehyde by Bi–Mo/g-C₃N₄ in Aqueous Solution

Programmable C−N Bond Formation through Radical‐Mediated Chemistry in Plasma‐Microdroplet Fusion

Programmable C−N Bond Formation through Radical‐Mediated Chemistry in Plasma‐Microdroplet Fusion

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Heterojunction WO3–BiVO4 Photoanodes for TEMPO-Mediated Benzyl Alcohol Dehydrogenation in Organic Media

Cited by 3 publications

References 42 publications

Highly Selective Photooxidation of Benzyl Alcohol to Benzaldehyde by Bi–Mo/g-C3N4 in Aqueous Solution

Highly Selective Photooxidation of Benzyl Alcohol to Benzaldehyde by Bi–Mo/g-C3N4 in Aqueous Solution

Programmable C−N Bond Formation through Radical‐Mediated Chemistry in Plasma‐Microdroplet Fusion

Programmable C−N Bond Formation through Radical‐Mediated Chemistry in Plasma‐Microdroplet Fusion

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Product

Resources

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Heterojunction WO₃–BiVO₄ Photoanodes for TEMPO-Mediated Benzyl Alcohol Dehydrogenation in Organic Media

Highly Selective Photooxidation of Benzyl Alcohol to Benzaldehyde by Bi–Mo/g-C₃N₄ in Aqueous Solution

Highly Selective Photooxidation of Benzyl Alcohol to Benzaldehyde by Bi–Mo/g-C₃N₄ in Aqueous Solution