Visible light promoted photocatalytic water oxidation: proton and electron collection via a reversible redox dye mediator

Walsh, Dominic; Sanchez‐Ballester, Noelia M.; Ting, Valeska P.; Ariga, Katsuhiko; Weller, Mark T.

doi:10.1039/c6cy00139d

Cited by 12 publications

(8 citation statements)

References 23 publications

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“…An efficient photocatalyst must possess chemical and physical stability, must be cheap and nontoxic in nature 13 . Several semiconductor materials such as TiO 2 , titanate nanosheets 14 , cobalt hydroxide-amino complex 15 , ZnO 16 , CdS, g-C 3 N 4 and Ag 3 PO 4 , and their nanostructure assemblies have been extensively employed as photocatalysts 17 .…”

Section: Introductionmentioning

confidence: 99%

TiO2 decorated functionalized halloysite nanotubes (TiO2@HNTs) and photocatalytic PVC membranes synthesis, characterization and its application in water treatment

Mishra

Mukhopadhyay

2019

Sci Rep

105

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In this study photocatalyst, TiO2@HNTs were prepared by synthesizing TiO2 nanoparticles in situ on the functionalized halloysite nanotubes (HNTs) surface. Photocatalytic PVC membrane TiO2@HNTs M2 (2 wt.%) and TiO2@HNTs M3 (3 wt.%) were also prepared. Photocatalyst TiO2@HNTs and photocatalytic PVC membranes were used to study the photocatalytic activity against the methylene blue (MB) and rhodamine B (RB) dyes in UV batch reactor. The structure and morphology of photocatalyst and photocatalytic PVC membrane were characterized by fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray (EDX), transmission electron microscopy (TEM), UV-Vis spectrophotometer and photoluminescence (PL). The PL study showed that the oxygen vacancies and surface hydroxyl groups present on the surface of TiO2@HNTs act as excellent traps for charge carrier, reducing the electron-hole recombination rate.TiO2@HNTs 2 (2 wt.%) and TiO2@HNTs 3 (3 wt.%) degraded MB dye up to 83.21%, 87.47% and RB dye up to 96.84% and 96.87%, respectively. TiO2@HNT photocatalyst proved to be stable during the three consecutive cycle of photocatalytic degradation of the RB dye. TiO2@HNTs M2 and TiO2@HNTs M3 degraded MB dye up to 27.19%, 42.37% and RB dye up to 30.78%, 32.76%, respectively. Photocatalytic degradation of both the dyes followed the first-order kinetic model. Degradation product analysis was done using the liquid chromatography–mass spectrometry (LC-MS) and the results showed that the dye degradation was initiated by demethylation of the molecule. MB and RB dye degradation reaction were tested by TBA and IPA as OH* and H+ scavengers respectively. Mechanism of photocatalytic activity of TiO2@HNTs and photocatalytic PVC membrane were also explained.

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Section: Introductionmentioning

confidence: 99%

TiO2 decorated functionalized halloysite nanotubes (TiO2@HNTs) and photocatalytic PVC membranes synthesis, characterization and its application in water treatment

Mishra

Mukhopadhyay

2019

Sci Rep

105

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“…If Pt was replaced with MoS 2 as an alternative co-catalyst, ethane was again the main product (1.3 μmol g cat –1 h –1 for P25|MoS 2 and 3.5 μmol g cat –1 h –1 for NCN CN x |MoS 2 ). The evolution of H 2 was suppressed by adding [CoCl(NH 3 ) 5 ]Cl 2 as an electron scavenger, 27 causing a sharp decline in the ethane production rate (no ethane detected for P25|Pt and 1.4 μmol g cat –1 h –1 for NCN CN x |Pt) and a significant increase in the absolute ethylene production (0.5 μmol g cat –1 h –1 for P25|Pt and 7.1 μmol g cat –1 h –1 for NCN CN x |Pt) ( Table S4 ). These experiments support the role of hydrogen in ethane production.…”

Section: Resultsmentioning

confidence: 99%

“…. The evolution of H 2 was suppressed by adding [CoCl(NH 3 ) 5 ]Cl 2 as an electron scavenger, 27 causing a sharp decline in the ethane production rate (no ethane detected for P25|Pt and 1.4 μmol g cat −1 h −1 for NCN CN x |Pt) and a significant increase in the absolute ethylene production (0.5 μmol g cat −1 h −1 for P25|Pt and 7.1 S4). These experiments support the role of hydrogen in ethane production.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Conversion of Polyethylene Waste into Gaseous Hydrocarbons via Integrated Tandem Chemical–Photo/Electrocatalytic Processes

et al. 2021

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The chemical inertness of polyethylene makes chemical recycling challenging and motivates the development of new catalytic innovations to mitigate polymer waste. Current chemical recycling methods yield a complex mixture of liquid products, which is challenging to utilize in subsequent processes. Here, we present an oxidative depolymerization step utilizing diluted nitric acid to convert polyethylene into organic acids (40% organic acid yield), which can be coupled to a photo- or electrocatalytic decarboxylation reaction to produce hydrocarbons (individual hydrocarbon yields of 3 and 20%, respectively) with H 2 and CO 2 as gaseous byproducts. The integrated tandem process allows for the direct conversion of polyethylene into gaseous hydrocarbon products with an overall hydrocarbon yield of 1.0% for the oxidative/photocatalytic route and 7.6% for the oxidative/electrolytic route. The product selectivity is tunable with photocatalysis using TiO 2 or carbon nitride, yielding alkanes (ethane and propane), whereas electrocatalysis on carbon electrodes produces alkenes (ethylene and propylene). This two-step recycling process of plastics can use sunlight or renewable electricity to convert polyethylene into valuable, easily separable, gaseous platform chemicals.

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“…34 Alternatively, quinone derivatives as electron harvesters can replace irreversible electron acceptors. 35,36 The overall long term aim is the development of effective low toxicity, earth abundant photocatalytic systems.…”

Section: Discussionmentioning

confidence: 99%

Exploring effects of intermittent light upon visible light promoted water oxidations

Walsh

Patureau

Robertson

et al. 2017

Sustainable Energy Fuels

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Visible light promoted photocatalytic water oxidation: proton and electron collection via a reversible redox dye mediator

Abstract: A quinone analogue as reversible electron and proton collector in visible light promoted water oxidations was investigated. Reagents were incorporated into microporous silica with surface absorbed cobalt catalyst. Reversible storage molecules are an important step towards solar fuels.

Cited by 12 publications

References 23 publications

TiO2 decorated functionalized halloysite nanotubes (TiO2@HNTs) and photocatalytic PVC membranes synthesis, characterization and its application in water treatment

TiO2 decorated functionalized halloysite nanotubes (TiO2@HNTs) and photocatalytic PVC membranes synthesis, characterization and its application in water treatment

Conversion of Polyethylene Waste into Gaseous Hydrocarbons via Integrated Tandem Chemical–Photo/Electrocatalytic Processes

Exploring effects of intermittent light upon visible light promoted water oxidations

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