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Popova, G. Ya.

doi:10.1023/a:1026681321584

Cited by 98 publications

(32 citation statements)

References 15 publications

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“…During UV irradiation, new bands appeared (Figures 4 and S-4), assigned to mono and bidentate formate species adsorbed on the catalyst surface. 12,13,27,28 These species are commonly described as intermediates in the photooxidation of alcohols. 12,15,16,[29][30][31][32][33][34] We observed different vibration bands for bidentate formates on TiO 2 -L (maxima at 1600, 1373 and 1356 cm -1 ) and on TiO 2 -P25 (maxima at 1570, 1379, 1362 cm -1 ), probably because of a difference in the nature of the formation/adsorption site.…”

Section: Photocatalytic Activity and Selectivity Of Tio 2 -L And Tio ...mentioning

confidence: 99%

Operando Infrared (IR) Coupled to Steady-State Isotopic Transient Kinetic Analysis (SSITKA) for Photocatalysis: Reactivity and Mechanistic Studies

et al. 2013

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This paper reports the coupling of operando IR and SSITKA (Steady State Isotopic Transient Kinetic Analysis) for air purification studies from VOCs by photocatalysis. Methanol photooxidation has been used as a model reaction. A new photocatalyst (TiO 2 -L) has been studied and compared to the reference material TiO 2 -P25. The TOF and reaction rate have been calculated and compared. We show that TOF values are not really available in heterogeneous photocatalysis where the number of active site can vary from one TiO 2 material to the other and from one experimental setup to the other. The influence of methanol concentration and reaction temperature on photocatalytic activity and on selectivity was also investigated. TiO 2 -L is more active than TiO 2 -P25 at low methanol concentration and more selective at high methanol concentrations. SSITKA clarified the role of the surface formate species in the reaction mechanism. Most of these formate species are spectators and are not the main intermediates in alcohol photooxidation. A graduation was found in the efficiency of active sites on photocatalyst surfaces.

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Section: Photocatalytic Activity and Selectivity Of Tio 2 -L And Tio ...mentioning

confidence: 99%

Operando Infrared (IR) Coupled to Steady-State Isotopic Transient Kinetic Analysis (SSITKA) for Photocatalysis: Reactivity and Mechanistic Studies

et al. 2013

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“…It shows a spontaneous decrease of methanol bands after UV irradiation. New bands appearing during the photooxidation were assigned to CO 2 (2400-2200 cm -1 ), -C=O (1820-1670cm -1 ) and C-H vibration modes (1275-1100 cm -1 ) 25 . The IR-gas spectra during photooxidation (at RT) are presented in Figure 10.…”

Section: Photooxidation Reactivity and Temperature Effectmentioning

confidence: 99%

“…The bands detected at 2870, 1560 and 1370 cm -1 are assigned respectively to ν s (CH), ν as (COO) and ν s (COO) vibrations of bidentate formate species adsorbed on the catalyst surface. Those observed at 1715 and 1650 cm -1 are assigned to ν(C=O) vibrations of formic acid (or methylformate) hydrogen bonded and co-ordinately bonded to Lewis acid sites, respectively 13,25,26,27 (the IR spectra vs. time and temperature during photooxidation of methanol at different temperature are presented in Figure I in the supplementary materials). The IR band at 1570 cm -1 reached a maximum at 120°C which means that the temperature favours the formation of bidentate formate, thus explaining the increase of methanol photooxidation.…”

Section: Concentration Effectmentioning

confidence: 99%

New Operando IR Technique to Study the Photocatalytic Activity and Selectivity of TiO₂ Nanotubes in Air Purification: Influence of Temperature, UV Intensity, and VOC Concentration

et al. 2012

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The photooxidation of methanol, n-hexane and carbon monoxide using TiO 2nanotubes (TNTs) has been investigated by a new IR-operando technique. Following the photocatalytic reaction by time resolved IR spectroscopy coupled with mass spectrometry (MS) allowed a surface study of the photocatalyst with on line analysis of the products. The identification of the species adsorbed on the photocatalyst surface and those detected in the gas phase led to further clarify the photooxidation mechanisms. The characterization of the photocatalyst has been performed by IR, Raman, UV-visible, XRD, N 2 -sorption, SEM and TEM techniques. The activity and selectivity of the photocatalyst have been determined by quantitative studies using gas-IR and MS. For comparison, photooxidation reactions, using TiO 2 -P25 as reference, have been performed under the same conditions. The influence of different parameters such as temperature, VOC concentrations and UV irradiation intensities on the reactivity and selectivity of the photocatalytic reaction has been investigated. The 2 temperature effect has been shown by TPD measurements (from RT to 200°C). The TNTs material showed a higher reactivity and CO 2 -selectivity in comparison with TiO 2 -P25.

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“…Experimentally Fourier transform infrared spectroscopy report the coexistence of two different adsorption structures, a bidentate mode and an unsymmetrical structure 51 . This is in agreement with our result that the monodentate and bidentate bridging modes are energetically similar and likely to coexist.…”

Section: Anatase (101)mentioning

confidence: 99%

DSSC Anchoring Groups: A Surface Dependent Decision

O’Rourke¹,

Bowler²

2014

Preprint

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Electrodes in dye sensitised solar cells (DSSCs) are typically nanocrystalline anatase TiO 2 with a majority (101) surface exposed. Generally the sensitising dye employs a carboxylic anchoring moiety through which it adheres to the TiO 2 surface. Recent interest in exploiting the properties of differing TiO 2 electrode morphologies, such as rutile nanorods exposing the (110) surface and anatase electrodes with high percentages of the (001) surface exposed, begs the question of whether this anchoring strategy is best, irrespective of the majority surface exposed. Here we address this question by presenting density functional theory calculations contrasting the binding properties of two promising anchoring groups, phosphonic acid and boronic acid, to that of carboxylic acid. Anchor-electrode interactions are studied for the prototypical anatase (101) surface, along with the anatase (001) and rutile (110) surfaces. Finally the effect of using these alternative anchoring groups to bind a typical coumarin dye (NKX-2311) to these TiO 2 substrates is examined. Significant differences in the binding properties are found depending on both the anchor and surface, illustrating that the choice of anchor is necessarily dependent upon the surface exposed in the electrode. In particular the boronic acid is found to show the potential to be an excellent anchor choice for electrodes exposing the anatase (001) surface.

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Untitled

Cited by 98 publications

References 15 publications

Operando Infrared (IR) Coupled to Steady-State Isotopic Transient Kinetic Analysis (SSITKA) for Photocatalysis: Reactivity and Mechanistic Studies

Operando Infrared (IR) Coupled to Steady-State Isotopic Transient Kinetic Analysis (SSITKA) for Photocatalysis: Reactivity and Mechanistic Studies

New Operando IR Technique to Study the Photocatalytic Activity and Selectivity of TiO₂ Nanotubes in Air Purification: Influence of Temperature, UV Intensity, and VOC Concentration

DSSC Anchoring Groups: A Surface Dependent Decision

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Untitled

Cited by 98 publications

References 15 publications

Operando Infrared (IR) Coupled to Steady-State Isotopic Transient Kinetic Analysis (SSITKA) for Photocatalysis: Reactivity and Mechanistic Studies

Operando Infrared (IR) Coupled to Steady-State Isotopic Transient Kinetic Analysis (SSITKA) for Photocatalysis: Reactivity and Mechanistic Studies

New Operando IR Technique to Study the Photocatalytic Activity and Selectivity of TiO2 Nanotubes in Air Purification: Influence of Temperature, UV Intensity, and VOC Concentration

DSSC Anchoring Groups: A Surface Dependent Decision

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New Operando IR Technique to Study the Photocatalytic Activity and Selectivity of TiO₂ Nanotubes in Air Purification: Influence of Temperature, UV Intensity, and VOC Concentration