Photochemical evolution of hydrogen peroxide on lignins

Miglbauer, Eva; Gryszel, Maciej; Głowacki, Eric Daniel

doi:10.1039/c9gc04324a

Cited by 31 publications

(24 citation statements)

References 28 publications

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“…The results show that CD particles were photocatalytically active under simulated sunlight conditions and generated micromolar levels of H 2 O 2 (∼270 μM during 8 h of UV irradiation). Similar photocatalytic activity for H 2 O 2 synthesis under visible light has been observed in the case of TiO 2 , graphene-based nanomaterials, lignin, carbon nitride, and their related composites. − …”

Section: Resultssupporting

confidence: 62%

Carbon Dot-Triggered Photocatalytic Degradation of Cellulose Acetate

2021

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Chemical modification of biopolymers, before use in thermoplastic applications, can reduce the susceptibility to open environment degradation. We demonstrate carbon dots (CDs) as green photocatalytic triggers that can render the common cellulose derivative, cellulose acetate (CA), degradable under open environment relevant conditions. CD-modified cellulose acetate (CA + CD) films were subjected to UV-A irradiation in air and simulated sea water, and the degradation process was mapped by multiple spectroscopic, chromatographic, and microscopy techniques. The addition of CDs effectively catalyzed the deacetylation reaction, the bottleneck preventing biodegradation of CA. The photocatalytically activated degradation process led to significant weight loss, release of small molecules, and regeneration of cellulose fibers. The weight loss of CA + CD after 30 days of UV-A irradiation in air or simulated sea water was 53 and 43%, respectively, while the corresponding values for plain CA films were 12 and 4%. At the same time the weight average molar mass of CA + CD decreased from 62,000 to 11,000 g/mol and 15,000 g/mol during UV-A irradiation in air and simulated sea water, respectively, and the degree of substitution (DS) decreased from 2.2 to 1.6 both in air and in water. The aging in water alone did not affect the weight average molar mass, but the DS was decreased to 1.9. Control experiments confirmed the generation of hydrogen peroxide when aqueous CD dispersion was subjected to UV-A irradiation, indicating a free radical mechanism. These results are promising for the development of products, such as mulching films, with photocatalytically triggered environmental degradation processes.

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Section: Resultssupporting

confidence: 62%

Carbon Dot-Triggered Photocatalytic Degradation of Cellulose Acetate

2021

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“…Peroxides also absorb light at ~ 200 nm 31 , a measurable amount, <1 mg L -1 was detected after four hours of irradiation. A recent study by Miglbauer et al 32 has shown that lignin itself can produce hydrogen peroxide (H 2 O 2 ) upon UV irradiation, which could indicate that lignin moieties in our system are initiating the peroxide formation upon UV irradiation.…”

Section: Lignin and Extractives In Sawdustmentioning

confidence: 75%

‘Lignin and extractives first’ conversion of lignocellulosic residual streams using UV light from LEDs

et al. 2021

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“…Organic dyes and lignins have been investigated as a photocatalyst of oxygen reduction to H 2 O 2 usually in the presence of a sacrificial reagent, such as oxalate and formate. [78] Shiraishi et al [79] prepared resorcinol-formaldehyde resin (25) as a reddish-orange and d) emission spectra of the dense and 23′ film and the previously reported polythiophene film. All panels are reproduced with permission.…”

Section: Light-driven Reduction Of Oxygen To H 2 O 2 On Conjugated Polymer-based Photocathodesmentioning

confidence: 98%

Organic π‐Conjugated Polymers as Photocathode Materials for Visible‐Light‐Enhanced Hydrogen and Hydrogen Peroxide Production from Water

Oka

Winther‐Jensen

Nishide

2021

Advanced Energy Materials

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Hydrogen is also regarded to be a critical and indispensable clean fuel for sustainable energy systems because of its extremely high energy density of 142 kJ g −1 (vs 44 kJ g −1 for gasoline) and low pollution emissions. [2] However, hydrogen is presently produced by conversion of hydrocarbons or fossil fuels and is accompanied by enormous energy consumption and greenhouse gas emissions.Electrolytic water splitting for the production of hydrogen can be achieved using the excess electricity generated by photovoltaics. [3] Hydrogen can be used as fuel locally or reconverted into electrical energy with via fuel cells on demand. However, the energy lost during electrical conversion and chemical reaction is not small; hence, a more direct approach that uses the energy of sunlight to produce hydrogen in an on-site manner is strongly desired.The production of hydrogen through photo(electro)catalytic water-splitting has been extensively investigated using inorganic semiconductors, including metal oxides, such as TiO 2 , Cu 2 O, and Ga 2 O 3 , and chalcogenides such as CdS and CdSe. [4] This research was triggered by TiO 2 -catalyzed water-splitting that evolves oxygen when illuminated and is nowadays the benchmark photocatalyst for photoenergy conversion studies and the photo-oxidations of organic components during water and air purification. [5] While TiO 2 is characterized by a legendary long lifetime of holes to oxidize water, [6] TiO 2 absorbs only in the UV region due to its wide bandgap and is unable to reduce water for hydrogen evolution by itself because of its deep conduction band. Parallel approaches toward visible-light-driven reactions are being developed, including the bandgap engineering of semiconducting inorganics, the coupling of two semiconductors, the incorporation of cocatalysts that facilitate the reaction, and nanostructured particles. [7] In addition, inorganic semiconductors, which are often unstable in aqueous acidic and/ or alkaline solutions, are frequently composed of precious or toxic metals, and the reaction often requires the assistance of a sacrificial reagent or a significant bias voltage. Separating the hydrogen and oxygen gases evolved from the inorganic semiconductor particles suspended in water is also problematic.Photoelectrocatalytic water-splitting has also been studied using pure organic semiconductors as alternatives toThe photo(electro)chemical reduction of water and oxygen to produce hydrogen (water-splitting) and hydrogen peroxide, respectively, are well developed with inorganic semiconductors. In contrast, organic π-conjugated polymers, especially precisely synthesized ones, have been extensively studied as photoharvesting and charge-separating materials in dry photoelectron-conversion devices, such as organic photovoltaic cells. However, the use of conjugated polymers as photocathodes; i.e., photoelectrocalatalytic reduction-active materials in direct contact with aqueous electrolytes, has been less explored. This review describes the fundamentals of the electrochemistry ...

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Photochemical evolution of hydrogen peroxide on lignins

Abstract: Means of sustainable on-demand hydrogen peroxide production are sought after for numerous industrial, agricultural, and environmental applications.

Cited by 31 publications

References 28 publications

Carbon Dot-Triggered Photocatalytic Degradation of Cellulose Acetate

Carbon Dot-Triggered Photocatalytic Degradation of Cellulose Acetate

‘Lignin and extractives first’ conversion of lignocellulosic residual streams using UV light from LEDs

Organic π‐Conjugated Polymers as Photocathode Materials for Visible‐Light‐Enhanced Hydrogen and Hydrogen Peroxide Production from Water

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