Formation of different products during photo-catalytic reaction on TiO2 suspension in water with and without 2-propanol under diverse ambient conditions

Dey, G.R.; Pushpa, K. K.

doi:10.1163/156856707781749883

Cited by 25 publications

(21 citation statements)

References 52 publications

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“…The vinoxyl radical is in turn a known precursor of acetaldehyde, which is also observed among the products of CO 2 reduction. The proposed complex pathway avoids intermediates which would block the process before reaching methane, while the intertwined reduction and oxidation steps, as well as the recycling of CO 2 , partially account for the poor quantum efficiency of the CO 2 reduction process [117][118][119]. The glyoxal pathway appears to be an important step in understanding the mechanism of this reaction.…”

Section: Possible Reaction Pathways For Co 2 Reductionmentioning

confidence: 98%

Photocatalytic conversion of CO2 into value-added and renewable fuels

2015

Applied Surface Science

383

188

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Section: Possible Reaction Pathways For Co 2 Reductionmentioning

confidence: 98%

Photocatalytic conversion of CO2 into value-added and renewable fuels

2015

Applied Surface Science

383

188

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“…The formation of hydroxylated intermediates of halogenated aromatic compounds [28] during photo-catalytic degradation has established the phenomenon of • OH radical generation. As a continuation to our earlier work on chemical reduction of carbon dioxide both in commercially available CO 2 and in situ generated CO 2 through mineralization of organic compounds to different products [31][32][33][34][35] such as CO, CH 4 , etc., we have carried out benzene degradation/oxidation to phenol in an exhaustive way using TiO 2 photo-catalyst as a suspension in water. In this paper, we have presented an argument on the basis of the results obtained from the present work about the formation of phenol followed by the reactions with h ?…”

Section: Introductionmentioning

confidence: 79%

Significant roles of oxygen and unbound •OH radical in phenol formation during photo-catalytic degradation of benzene on TiO2 suspension in aqueous system

Dey

2009

Res Chem Intermed

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Studies on photo-catalytic degradation of benzene using TiO 2 photocatalyst as a suspension in water is reported. Degradation studies have been carried out using 350 nm UV light. Phenol, a photo-catalytic product of benzene, was monitored under varying experimental conditions such as amount of TiO 2 , concentration of benzene, photolysis time, ambient (air, O 2 , Ar, N 2 O and N 2 O-O 2 mixture), etc. The phenol yields in both aerated and O 2 -purged systems increased with the photolysis time. In contrast to oxygenated systems, the yields of phenol in deoxygenated (viz. Ar-purged and N 2 O-purged) systems were quite low (*30 lM) and remained steady. H 2 O 2 yields in all these systems were also monitored, and found lower than an order of magnitude as compared to phenol yields for the respective systems. The rate of phenol production in aerated 1 mM benzene solution containing 0.05% TiO 2 suspension was evaluated at 12.3 lM min -1 which is lower than the rate obtained in an O 2 -saturated system (22.4 lM min -1 ). The low yields of phenol in both Ar-and N 2 O-purged systems, and also the increasing trends in oxygenated systems, together reveal that, for the phenol formation with an enhanced rate, oxygen is essential. In the present study, it is implied that the photo-generated hole, which is mainly an • OH radical, is either freely available in the aqueous phase or migrates to the aqueous phase from the catalyst surface, to react with benzene to produce HO-adduct radical. Later, following reaction with oxygen, the adduct produces phenol. On the other hand, h ? and surface adsorbed • OH radical, being trapped/bonded due to rigid association with the catalyst surface, were not able to generate phenol under similar experimental conditions. The mechanism of phenol formation with TiO 2 photolysis in an aqueous system is rechecked, on the basis of present results on h ? /surface adsorbed • OH radical/unbound • OH radical scavenging by benzene, collectively with previous reports on various systems.

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“…In the CO 2 -purged system containing TiO 2 suspension in water in the presence of 2-propanol, the yields of CO and CH 4 and their formation rates are higher than those obtained in the system without 2-propanol. CO generation has been known previously in TiO 2 system but in different systems, and its yield depends mainly on the reaction conditions [71,72,100]. The generation of methane in these systems has been explained previously as due to the free radical-induced reduction reaction of CO 2 .…”

Section: Methane Yield Has Been Reported To Be Higher In the Aerated mentioning

confidence: 92%

“…Commercially available as well as laboratory-synthesized TiO 2 photocatalysts in different forms have been used for CO 2 reduction [26,[28][29][30][31][70][71][72][73][74][75] to generate different products such as HCOOH, HCHO, methanol, hydrocarbons, CO, etc. Extensive research on photochemical reduction of CO 2 has been carried out in the recent past to produce the above-mentioned products, which depend on various factors.…”

Section: Photochemical Reduction Of Comentioning

confidence: 99%

“…The formation rates and the yields of CO and CH 4 in N 2 O-purged 2-propanol aqueous solution containing TiO 2 suspensions have been reported to be different [72]. The higher formation rate and the yield of CO compared with CH 4 under identical conditions indicate that the all of the CO generated during CO 2 reduction does not convert to CH 4 instantly.…”

Section: Methane Yield Has Been Reported To Be Higher In the Aerated mentioning

confidence: 99%

See 1 more Smart Citation

Formation of different products during photo-catalytic reaction on TiO2 suspension in water with and without 2-propanol under diverse ambient conditions

Cited by 25 publications

References 52 publications

Photocatalytic conversion of CO2 into value-added and renewable fuels

Photocatalytic conversion of CO2 into value-added and renewable fuels

Significant roles of oxygen and unbound •OH radical in phenol formation during photo-catalytic degradation of benzene on TiO2 suspension in aqueous system

Transformation of Carbon Dioxide to Useable Products through Free Radical‐Induced Reactions

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