Photocatalytic hydrogenation of acetophenone derivatives and diaryl ketones on polycrystalline titanium dioxide

Kohtani, Shigeru; Yoshioka, Eito; Saito, Kenji; Kudo, Akihiko; Miyabe, Hideto

doi:10.1016/j.catcom.2010.04.022

Cited by 51 publications

(44 citation statements)

References 31 publications

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“…This reaction was recently applied to a micro-reaction system by Matsushita et al [35,36]. Kohtani et al recently demonstrated that the P25 TiO2 powder exhibited the excellent photocatalytic activity to hydrogenate several aromatic ketones into corresponding secondary alcohols under the combination of UV light irradiation and deaerated conditions in ethanol as summarized in Table 3 [37]. Acetaldehyde was simultaneously produced in the oxidation of ethanol by h + generated in the VB or those trapped at the surface sites on TiO2.…”

Section: Hydrogenation Of Carbonyl Compoundsmentioning

confidence: 99%

“…acetophenone (Ar = C6H5, R = Me) to 1-phenylethanol in 97% yield (highlighted in gray color in Table 3). They also found that most of the reaction rates depend on the reduction potential (Ered) of substrates, except for 2,2,2-trifluoroacetophenone [37]. In general, aldehydes are more reactive than ketones because of electronic and steric factors.…”

Section: Hydrogenation Of Carbonyl Compoundsmentioning

confidence: 99%

“…2 [38,39]. In contrast, the photocatalytic hydrogenation did not occur upon TiO2, since the CB level of TiO2 is too positive to reduce the aliphatic ketones [37]. Yanagida and co-workers reported that acetaldehyde was reduced and oxidized upon the UV irradiated ZnS nano-crystallites (2 -5 nm) in water as depicted in Scheme 3 [38].…”

Section: Hydrogenation Of Carbonyl Compoundsmentioning

confidence: 99%

“…For examples, the selective hydrogenations were reported for the reactions of CH3C≡CH to CH3CH=CH2 on Pt/TiO2 (rutile) [17], the aromatic ketones to the corresponding secondary alcohols on the P25 TiO2 [37], the aliphatic ketones to the corresponding alcohols on the ZnS nano-crystallite [39], and nitroaromatics to the corresponding amino-compounds on TiO2 [67][68][69]. In addition, the selective formation of methanol from CO2 [53][54][55][56] and NH3 from NO3 - [65,66] has been received much attention to solve the environmental issues.…”

Section: Concluding Remarks and Future Directionsmentioning

confidence: 99%

“…[37] (summarized in Table 3) was supported by a Grant-in-Aid for Scientific Research (no. 21590052 and no.…”

Section: Acknowledgementmentioning

confidence: 99%

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Photocatalytic Hydrogenation on Semiconductor Particles

Kohtani¹,

Yoshioka²,

Miyabe³

2012

Hydrogenation

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Section: Hydrogenation Of Carbonyl Compoundsmentioning

confidence: 99%

Section: Hydrogenation Of Carbonyl Compoundsmentioning

confidence: 99%

Section: Hydrogenation Of Carbonyl Compoundsmentioning

confidence: 99%

Section: Concluding Remarks and Future Directionsmentioning

confidence: 99%

“…[37] (summarized in Table 3) was supported by a Grant-in-Aid for Scientific Research (no. 21590052 and no.…”

Section: Acknowledgementmentioning

confidence: 99%

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Photocatalytic Hydrogenation on Semiconductor Particles

Kohtani¹,

Yoshioka²,

Miyabe³

2012

Hydrogenation

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Probing the Role of Surface Energetics of Electrons and their Accumulation in Photoreduction Processes on TiO₂

Molinari

Maldotti²,

Амаделли

2014

Chemistry A European J

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We address the role of the energetics of photogenerated electrons in the reduction of 4-nitrobenzaldehyde on TiO2. This model molecule bears two functional groups featuring different reducibilities. Electrochemistry shows that reduction to 4-aminobenzyl alcohol occurs in entirely distinct potential ranges. Partial reduction of the -NO2 group, affording 4-aminobenzaldehyde, takes place through surface states at potentials positive of the flatband potential (E(fb)). Dark currents caused by reduction of the aldehyde group are observed only at potentials more negative than E(fb), and the process requires an electron accumulation regime. Photocatalysis with TiO2 suspensions agrees with the electrochemical data. In particular, reduction of the nitro group is a relatively fast process (k=0.059 s(-1)), whereas that of the aldehyde group is slower (k=0.001 s(-1)) and requires electron photoaccumulation. Control of the photogenerated charge is a prospective means for achieving chemoselective reductions.

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Recent Development in Defects Engineered Photocatalysts: An Overview of the Experimental and Theoretical Strategies

Zafar

et al. 2021

Energy & Environ Materials

119

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Photocatalysis is considered as one of the most appealing advanced technology in solution to the environmental problems and non-renewable energy resources depletion with a variety of applications such as synthesis, industry, water, and environmental remediation. [1][2][3][4][5] Although enormous research has been carried out with impressive advancement in photoactive materials, the process of photocatalysis still suffers from low efficiency and poor stability that is far below the requisites for practical applications. The three main key steps that governs photocatalysis includes light absorption, generation of electron-hole pairs, followed by their migration from the bulk to the surface and initiation of interfacial redox reactions upon their arrival at the active sites. [6,7] In order to boost up the photocatalytic efficiency, various approaches have been adopted such as doping, crystal facet exposure, synthesis parameters, reaction environments, hybridization, dimensions, and morphology tuning of photocatalysts. [8][9][10][11] However, the efficiency of these photocatalysts is still limited by their cost, wide band gap, lower stability and poor charge transfer kinetics. [12] In order to address the aforementioned issues, extensive research has been conducted to increase the surface area, such as nanowires, nanosheets, nanotubes, and other hierarchical nanostructures are developed with abundant active sites for redox reactions. [13][14][15][16][17] Similarly, to enhance charge separation, hetrojunctions were explored utilizing different semiconductors with appreciable band alignment. [18][19][20] Alternatively, effective light absorption with undoubtedly decreased recombination and improved photocatalytic performance through defect engineering have been reported. [21,22] Defects in semiconductors greatly alter carrier concentration and interface reaction affecting the overall process efficiency of a photocatalyst. Thus, defects are the most frequently investigated scenario for tuning the properties of photocatalyst. [23,24] However, defects are detrimental to photocatalysis in regard of the recombination centers and lack detailed explanation in terms of carrier concentration, transfer dynamics, band structure, and interface profiles. [25] The emerging trend of defect engineering still brought the opportunity of deliberately manipulating the photocatalyst properties. Although the influence of defects on photocatalytic performance has been previously elaborated in some reviews, their optimization and intrinsic role in photocatalysis is still elusive. [12,[25][26][27][28] Therefore, some novel strategies based on advanced modeling theoretical and experimental knowledge are of great need to elucidate the role of defects in photocatalysis. Subsequently, it has been suggested that different synthesis strategies offer different mechanisms thus altering the band structure, carrier mobility, and so reactivity (Figure 1). It therefore remains a challenging task to account the relationship between defect chemistry and per...

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Photocatalytic hydrogenation of acetophenone derivatives and diaryl ketones on polycrystalline titanium dioxide

Cited by 51 publications

References 31 publications

Photocatalytic Hydrogenation on Semiconductor Particles

Photocatalytic Hydrogenation on Semiconductor Particles

Probing the Role of Surface Energetics of Electrons and their Accumulation in Photoreduction Processes on TiO₂

Recent Development in Defects Engineered Photocatalysts: An Overview of the Experimental and Theoretical Strategies

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Photocatalytic hydrogenation of acetophenone derivatives and diaryl ketones on polycrystalline titanium dioxide

Cited by 51 publications

References 31 publications

Photocatalytic Hydrogenation on Semiconductor Particles

Photocatalytic Hydrogenation on Semiconductor Particles

Probing the Role of Surface Energetics of Electrons and their Accumulation in Photoreduction Processes on TiO2

Recent Development in Defects Engineered Photocatalysts: An Overview of the Experimental and Theoretical Strategies

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Product

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Probing the Role of Surface Energetics of Electrons and their Accumulation in Photoreduction Processes on TiO₂