Photolysis of aqueous poly(vinyl alcohol) solution by heterogeneous TiO<sub>2</sub>/Pt catalyst

Nishimoto, Sei‐ichi; Ohtani, Bunsho; Shirai, Hiroshi; Kagiya, Tsutomu

doi:10.1002/pol.1985.130230304

Cited by 5 publications

(5 citation statements)

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“…The noble metal (or its oxide) deposits have been interpreted to act as a catalyst for the H 2 evolution by e - , i.e., they reduce the activation energy for water reduction. Isotope distribution studies for the photocatalytic splitting of water have proved the catalytic effect of Pt deposits. , Kraeutler and Bard have reported the photocatalytic preparation of TiO 2 −Pt from aqueous solution of chloroplatinic acid (H 2 PtCl 6 ) and used for decarboxylation of acetic acid, the photo-Kolbe reaction, producing methane and carbon dioxide under deaerated conditions. , By using platinized TiO 2 photocatalysts in the absence of O 2 , generally, hydrogen evolution proceeds as a counter reaction of oxidation by h + , e.g., primary and secondary alcohols are converted into aldehydes and ketones with the evolution of equimolar amount of H 2 . − Pt loading also gives a decisive effect for these reactions; a significant amount of the products was seen only when Pt was loaded effectively. Thus, an extensive number of reactions by TiO 2 −Pt under deaerated conditions have been reported so far, but the limited number of investigations showed the mechanism and the relation between properties of Pt deposits and photocatalytic activities.…”

Section: Introductionmentioning

confidence: 99%

Role of Platinum Deposits on Titanium(IV) Oxide Particles: Structural and Kinetic Analyses of Photocatalytic Reaction in Aqueous Alcohol and Amino Acid Solutions

et al. 1997

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Photocatalytic reaction at 298 K by platinum-loaded titanium(IV) oxide (TiO 2 -Pt) particles suspended in deaerated aqueous solutions of 2-propanol or (S)-lysine (Lys) was investigated. The TiO 2 catalysts with various amounts of Pt loadings were prepared by impregnation from aqueous chloroplatinic acid solution onto a commercial TiO 2 (Degussa P-25) followed by hydrogen reduction at 753 K. The physical properties of deposited Pt, e.g., particle size, surface area, and electronic state, were studied respectively by transmission electron microscopy, volumetric gas adsorption measurement, and X-ray photoelectron spectroscopy as well as infrared spectroscopy of adsorbed carbon monoxide. The increase in Pt amount mainly resulted in an increase of the number of Pt deposits, not of their size. The catalysts were suspended in the aqueous solutions and photoirradiated at a wavelength >300 nm under an argon (Ar) atmosphere. The overall rate of photocatalytic reactions for both 2-propanol and Lys, corresponding to the rate of consumption of these substrates, was negligible without Pt loading, increased drastically with the loading up to ca. 0.3%, and was almost constant or a little decreased by the further loadings. However, the rate of formation of pipecolinic acid (PCA) from Lys was improved gradually with a increase of Pt loading up to ca. 2 wt %. These dependences were discussed as a function of Pt surface area, which is employed as a measure that includes the properties of both number and size of Pt deposits. For the photocatalytic dehydrogenation of 2-propanol, the rate dependence could be interpreted semiquantitatively with the model that only the TiO 2 particles loaded with at least one Pt deposit can photocatalyze, but the reaction rate is independent of the number of Pt deposits. Therefore, the overall rate is proportional to the number of Pt-loaded TiO 2 particles. On the other hand, for the interpretation of the rate of PCA and H 2 productions, the number of Pt deposits on each TiO 2 particle had to be taken into account. The efficient production of PCA at higher Pt loadings was attributed to the reduction of a Schiff base intermediate produced via oxidation of Lys with positive holes and subsequent intramolecular condensation at the Pt deposit that is close to the site for the oxidation. Otherwise, photoexcited electrons are consumed for H 2 production and the intermediate remains unreduced or undergoes further oxidation. It was suggested that the intermediate produced at the TiO 2 surface sites within a distance of several nanometers from the Pt deposit undergoes efficient reduction to PCA. Thus, the importance of the distribution of Pt deposits for the preparation of highly active and selective TiO 2 -Pt photocatalyst has been clearly demonstrated.

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Section: Introductionmentioning

confidence: 99%

Role of Platinum Deposits on Titanium(IV) Oxide Particles: Structural and Kinetic Analyses of Photocatalytic Reaction in Aqueous Alcohol and Amino Acid Solutions

et al. 1997

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“…By using platinized TiO 2 photocatalysts in the absence of O 2 , generally, hydrogen evolution proceeds as a counter reaction of oxidation by h ? , e.g., primary and secondary alcohols are converted into aldehydes and ketones with the evolution of H 2 [10,11]. Earlier we reported the defluoridation of PFBA using Pt-TiO 2 -P25.…”

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confidence: 98%

RETRACTED ARTICLE: Nano Pt–TiO2 for an efficient one-pot photocatalytic synthesis of quinaldines from anilines and ethanol

2011

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Nanosized platinum particles loaded on the TiO 2 nanoparticles were prepared to assess its photocatalytic activity in simple one-pot synthesis of quinaldines from anilines in ethanol using UV light. The catalyst was characterized by X-ray diffraction (XRD), high-resolution transmission electron microscopy, X-ray photoelectron spectra (XPS), Brunauer-Emmer-Teller surface area, atomic force microscope and diffuse reflectance spectra. XRD patterns revealed that the crystal structure of Pt-TiO 2 resembled anatase phase of TiO 2 . The UV-Vis spectra indicated an increase in absorption of visible light when compared to TiO 2 . XPS analysis reveals that platinum particles are present mainly in metallic form. Furthermore, TEM analysis showed non-spherical-shaped Pt-TiO 2 nanoparticles of the diameter 10-30 nm. Upon irradiation in the presence of Pt-TiO 2 , aniline and oxidation products derived from ethanol undergo condensation-cyclization to afford quinaldines. Higher efficiency of Pt-TiO 2 than Au-TiO 2 in the conversion of aniline to quinaldines is due to the higher work function of Pt.

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“…Nishimoto et al investigated pH-regulated photocatalysis with a TiO 2 /Pt suspension for the degradation of a PEG polymer in an aqueous solution. [9] Compared with watersoluble polymers, the photodegradation of insoluble polymers in TiO 2 aqueous dispersions has received relatively less attention. In 1996, some researchers carried out photocatalytic degradation of polymers, such as polyvinylchloride (PVC) particles, polyvinylidene chloride (PVLC) co-polymer, and PVC films in a TiO 2 suspension aqueous solution under UV light and/ or natural sunlight.…”

Section: Acetonitrilementioning

confidence: 99%

“…Nishimoto et al. investigated pH‐regulated photocatalysis with a TiO 2 /Pt suspension for the degradation of a PEG polymer in an aqueous solution [9] . Compared with water‐soluble polymers, the photodegradation of insoluble polymers in TiO 2 aqueous dispersions has received relatively less attention.…”

Section: Photocatalytic Conversionmentioning

confidence: 99%

Plastic Waste Conversion by Leveraging Renewable Photo/Electro‐Catalytic Technologies

Li,

Ma,

Zhao

et al. 2024

ChemSusChem

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Plastics have revolutionized our lives; however, the exponential growth of their usage has led to a global crisis. More sustainable strategies are needed to address this dilemma and transform the plastics economy from a linearity to a circular model. Herein, we systematically summarize the recent progress in renewable energy‐driven plastic conversion strategies, including photocatalysis, electrocatalysis, and their integration. By introducing the significant works, the design principles, mechanisms, and system regulations, we decipher and compare the various aspects of plastic conversion. These approaches show high reactivity and selectivity under environmentally benign conditions and provide alternative reaction pathways for plastic conversion. Plastic upcycling as a chemical feedstock can yield value‐added chemicals and fuels, contributing to the establishment of a sustainable and circular economy. Additionally, several innovations in reaction engineering and system designs are presented. Finally, the challenges and perspectives of sustainable energy‐driven plastic conversion technologies are comprehensively discussed.

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Photolysis of aqueous poly(vinyl alcohol) solution by heterogeneous TiO₂/Pt catalyst

Cited by 5 publications

References 21 publications

Role of Platinum Deposits on Titanium(IV) Oxide Particles: Structural and Kinetic Analyses of Photocatalytic Reaction in Aqueous Alcohol and Amino Acid Solutions

Role of Platinum Deposits on Titanium(IV) Oxide Particles: Structural and Kinetic Analyses of Photocatalytic Reaction in Aqueous Alcohol and Amino Acid Solutions

RETRACTED ARTICLE: Nano Pt–TiO2 for an efficient one-pot photocatalytic synthesis of quinaldines from anilines and ethanol

Plastic Waste Conversion by Leveraging Renewable Photo/Electro‐Catalytic Technologies

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Photolysis of aqueous poly(vinyl alcohol) solution by heterogeneous TiO2/Pt catalyst

Cited by 5 publications

References 21 publications

Role of Platinum Deposits on Titanium(IV) Oxide Particles: Structural and Kinetic Analyses of Photocatalytic Reaction in Aqueous Alcohol and Amino Acid Solutions

Role of Platinum Deposits on Titanium(IV) Oxide Particles: Structural and Kinetic Analyses of Photocatalytic Reaction in Aqueous Alcohol and Amino Acid Solutions

RETRACTED ARTICLE: Nano Pt–TiO2 for an efficient one-pot photocatalytic synthesis of quinaldines from anilines and ethanol

Plastic Waste Conversion by Leveraging Renewable Photo/Electro‐Catalytic Technologies

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Photolysis of aqueous poly(vinyl alcohol) solution by heterogeneous TiO₂/Pt catalyst