scholarly journals Au Modified F-TiO2 for Efficient Photocatalytic Synthesis of Hydrogen Peroxide

Molecules ◽  
2021 ◽  
Vol 26 (13) ◽  
pp. 3844
Author(s):  
Lijuan Li ◽  
Bingdong Li ◽  
Liwei Feng ◽  
Xiaoqiu Zhang ◽  
Yuqian Zhang ◽  
...  
Keyword(s):  
Hydrogen Peroxide ◽  
Reaction System ◽  
Reaction Medium ◽  
Pure Tio2 ◽  
H2o2 Production ◽  
Tio2 Photocatalyst ◽  
H2o2 Decomposition ◽  
Spin Resonance ◽  
Photocatalytic Synthesis

In this work, Au-modified F-TiO2 is developed as a simple and efficient photocatalyst for H2O2 production under ultraviolet light. The Au/F-TiO2 photocatalyst avoids the necessity of adding fluoride into the reaction medium for enhancing H2O2 synthesis, as in a pure TiO2 reaction system. The F− modification inhibits the H2O2 decomposition through the formation of the ≡Ti–F complex. Au is an active cocatalyst for photocatalytic H2O2 production. We compared the activity of TiO2 with F− modification and without F− modification in the presence of Au, and found that the H2O2 production rate over Au/F-TiO2 reaches four times that of Au/TiO2. In situ electron spin resonance studies have shown that H2O2 is produced by stepwise single-electron oxygen reduction on the Au/F-TiO2 photocatalyst.

Harnessing low energy photons (635 nm) for the production of H2O2 using upconversion nanohybrid photocatalysts

2016 ◽  
Vol 9 (3) ◽  
pp. 1063-1073 ◽  
Author(s):  
Hyoung-il Kim ◽  
Oh Seok Kwon ◽  
Sujeong Kim ◽  
Wonyong Choi ◽  
Jae-Hong Kim
Keyword(s):  
Hydrogen Peroxide ◽  
Low Energy ◽  
Time In Literature ◽  
First Time ◽  
Photocatalytic Synthesis ◽  
Triplet Triplet Annihilation

This study demonstrates, for the first time in literature, in situ photocatalytic synthesis of hydrogen peroxide (H2O2) through sensitized triplet–triplet annihilation (TTA) upconversion (UC) of low-energy, sub-bandgap photons.

scholarly journals Optical measurement of the catalase-hydrogen peroxide intermediate (Compound I) in the liver of anaesthetized rats and its implication to hydrogen peroxide production in situ

1975 ◽  
Vol 146 (1) ◽  
pp. 67-77 ◽  
Author(s):  
N Oshino ◽  
D Jamieson ◽  
T Sugano ◽  
B Chance
Keyword(s):  
Hydrogen Peroxide ◽  
Ethanol Oxidation ◽  
Optical Measurement ◽  
Intermediate Compound ◽  
Whole Body ◽  
H2o2 Production ◽  
Compound I ◽  
Anaesthetized Rats ◽  
Endogenous Substrates

The spectrophotometric determination of the catalase-H2O2 intermediate (Compound I) was extended to the liver in situ in anaesthetized rats. The rate of H2O2 production was determined for the liver in situ with endogenous substrates, and in the presence of excess of glycollate. Glycollate infusion doubled H2O2 production rate in the liver of air-breathing rats, and caused a fourfold increase when rats breathed O2 at 1 times 10(5) Pa. Hyperbaric O2 up to 6 times 10(5) Pa did not increase H2O2 generation supported by endogenous substrates, nor did it increase H2O2 production above that produced by 1 times 10(5) Pa O2 in glycollate-supplemented rats. The rates of ethanol oxidation via hepatic catalase and via alcohol dehydrogenase in the whole body were separately measured. The contribution of hepatic catalase to ethanol oxidation was found to be approx. 10 percent in endogenous conditions and increased to 30 percent or more of the total ethanol oxidation in rats supplemented with glycolate.

scholarly journals Electro-generation of hydrogen peroxide for electro-Fenton: Application in Glyphosate herbicide treatment

2017 ◽  
Vol 33 (4) ◽  
Author(s):  
Thanh Son Le ◽  
Tran Manh Hai ◽  
Doan Tuan Linh
Keyword(s):  
Hydrogen Peroxide ◽  
Ph Value ◽  
Current Intensity ◽  
H2o2 Production ◽  
Aquatic Life ◽  
Herbicide Treatment ◽  
Initial Ph ◽  
Glyphosate Herbicide ◽  
Save Energy

One of the major and serious pollution issues in an agriculture-based country as Vietnam is derived from herbicide, especially Glyphosate herbicide which can cause a massive quantity of adverse effects and acute toxicity to aquatic life and human health. Hence, this research focused on setting up an electro-Fenton system with a Pt gauze anode and a commercial carbon felt cathode for Glyphosate herbicide treatment with the primary mechanism based on the in situ hydrogen peroxide electro-generation and ferrous ion catalyst regeneration. This study investigated effect of initial pH and current intensity on both the amount of hydrogen peroxide production and the Glyphosate mineralization performance. The results indicated that the pH value was 3, the quantity of H2O2 production on cathode reached largest, then the Glyphosate mineralization performance was optimum, approximately 0.15 mg/L and 60% at 50 electrolysis time respectively. Moreover, when current intensity increased, the amount of H2O2 electro-generation increased, leading to better Glyphosate mineralization efficiency. Nonetheless, in order to minimize the electrode corrosion as well as save energy cost, the optimum current intensity was found being 0.5 A.

scholarly journals In-Situ Rheological Studies of Cationic Lignin Polymerization in an Acidic Aqueous System

Polymers ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 2982
Author(s):  
Samira Gharehkhani ◽  
Weijue Gao ◽  
Pedram Fatehi
Keyword(s):  
Molecular Weight ◽  
Reaction Time ◽  
Reaction System ◽  
Reaction Medium ◽  
Molar Ratio ◽  
Process Conditions ◽  
Trimethylammonium Chloride ◽  
Tan Δ ◽  
Lignin Polymerization

The chemistry of lignin polymerization was studied in the past. Insights into the rheological behavior of the lignin polymerization system would provide crucial information required for tailoring lignin polymers with desired properties. The in-situ rheological attributes of lignin polymerization with a cationic monomer, [2-(methacryloyloxy)ethyl] trimethylammonium chloride (METAC), were studied in detail in this work. The influences of process conditions, e.g., temperature, component concentrations, and shear rates, on the viscosity variations of the reaction systems during the polymerization were studied in detail. Temperature, METAC/lignin molar ratio, and shear rate increases led to the enhanced viscosity of the reaction medium and lignin polymer with a higher degree of polymerization. The extended reaction time enhanced the viscosity attributing to the larger molecular weight of the lignin polymer. Additionally, the size of particles in the reaction system dropped as reaction time was extended. The lignin polymer with a larger molecular weight and Rg behaved mainly as a viscose (tan δ > 1 or G″ > G′) material, while the lignin polymer generated with smaller molecular weight and shorter Rg demonstrated strong elastic characteristics with a tan (δ) lower than unity over the frequency range of 0.1−10 rad/s.

scholarly journals Efficient Photocatalytic Hydrogen Peroxide Production over TiO2 Passivated by SnO2

Catalysts ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 623 ◽  
Author(s):  
Guifu Zuo ◽  
Bingdong Li ◽  
Zhaoliang Guo ◽  
Liang Wang ◽  
Fan Yang ◽  
...  
Keyword(s):  
Surface Passivation ◽  
Reduction Reaction ◽  
Electron Spin Resonance Study ◽  
Tio2 Photocatalysts ◽  
H2o2 Decomposition ◽  
Spin Resonance ◽  
H2o2 Formation ◽  
Decomposition Of H2o2 ◽  
Spin Resonance Study

Photocatalysis provides an attractive strategy for synthesizing H2O2 at ambient condition. However, the photocatalytic synthesis of H2O2 is still limited due to the inefficiency of photocatalysts and decomposition of H2O2 during formation. Here, we report SnO2-TiO2 heterojunction photocatalysts for synthesizing H2O2 directly in aqueous solution. The SnO2 passivation suppresses the complexation and decomposition of H2O2 on TiO2. In addition, loading of Au cocatalyst on SnO2-TiO2 heterojunction further improves the production of H2O2. The in situ electron spin resonance study revealed that the formation of H2O2 is a stepwise single electron oxygen reduction reaction (ORR) for Au and SnO2 modified TiO2 photocatalysts. We demonstrate that it is feasible to enhance H2O2 formation and suppress H2O2 decomposition by surface passivation of the H2O2-decomposition-sensitive photocatalysts.

Production and decomposition dynamics of hydrogen peroxide in freshwater

2007 ◽  
Vol 4 (1) ◽  
pp. 49 ◽  
Author(s):  
Luc E. Richard ◽  
Barrie M. Peake ◽  
Steven A. Rusak ◽  
William J. Cooper ◽  
David J. Burritt
Keyword(s):  
Reactive Oxygen Species ◽  
Hydrogen Peroxide ◽  
Natural Waters ◽  
Formation Rate ◽  
Reaction System ◽  
Reactive Oxygen ◽  
Photochemical Reactions ◽  
Oxygen Species ◽  
Decay Rate Constant ◽  
H2o2 Decomposition

Environmental context. Hydrogen peroxide (H2O2) is the most stable reactive oxygen species (ROS) formed through irradiation of chromophoric dissolved organic matter (CDOM) in freshwater. It can act as a reductant or as an oxidant and decays largely through interaction with microorganisms via unknown mechanisms. In this way it can affect biological and chemical processes in natural waters and thus shape the ecosystem biogeochemistry. Abstract. Hydrogen peroxide (H2O2) is widely recognised as the most stable of the reactive oxygen species produced by solar radiation-driven photochemical reactions in natural waters. H2O2 concentrations were determined in a shallow fresh water system (water of Leith, Dunedin, New Zealand) by flow-injection analysis (FIA) using an acridinium ester chemiluminescent reaction system. Daytime measurements of H2O2 concentration showed a rapid increase from early morning (15 nM) to 1300 hours (491 nM), consistent with photochemical formation, lagging maximum solar irradiance by ~1.5 h. The wavelength dependency of H2O2 formation was studied and it was shown that UV-B, UV-A and PAR contributed 40, 33 and 27%, respectively. The average formation rate was 339 nM h–1 during springtime. The influence of biotic communities on the rate of H2O2 decomposition was also studied and the majority of decomposition was due to particles smaller than 0.22 μm. The overall first order decay rate constant was of the order of 7.1 h–1. The bacterial and algal communities in the water column and on the riverbed were primarily responsible for the decomposition of H2O2.

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