Photocatalytic Oxidation and Subsequent Hydrogenolysis of Lignin β-O-4 Models to Aromatics Promoted by In Situ Carbonic Acid

2018 ◽  
Vol 6 (11) ◽  
pp. 15032-15039 ◽  
Author(s):  
Yu Cao ◽  
Ning Wang ◽  
Xing He ◽  
Hong-Ru Li ◽  
Liang-Nian He
Keyword(s):  
Photocatalytic Oxidation ◽  
Carbonic Acid

Effectively enhancing conversion of cellulose to HMF by combining in-situ carbonic acid from CO2 and metal oxides

2018 ◽  
Vol 126 ◽  
pp. 151-157 ◽  
Author(s):  
Shuangshuang Jing ◽  
Xuefei Cao ◽  
Linxin Zhong ◽  
Xinwen Peng ◽  
Runcang Sun ◽  
...  
Keyword(s):  
Metal Oxides ◽  
Carbonic Acid

scholarly journals In Situ Construction of a MgSn(OH)6 Perovskite/SnO2 Type-II Heterojunction: A Highly Efficient Photocatalyst towards Photodegradation of Tetracycline

Nanomaterials ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 53 ◽  
Author(s):  
Yuanyuan Li ◽  
Xiaofang Tian ◽  
Yaoqiong Wang ◽  
Qimei Yang ◽  
Yue Diao ◽  
...  
Keyword(s):  
Photocatalytic Activity ◽  
Ultraviolet Irradiation ◽  
Photocatalytic Oxidation ◽  
Photocatalytic Performance ◽  
Diffuse Reflectance Spectroscopy ◽  
Active Species ◽  
Growth Strategy ◽  
Type Ii ◽  
Highly Efficient

Using solar energy to remove antibiotics from aqueous environments via photocatalysis is highly desirable. In this work, a novel type-II heterojunction photocatalyst, MgSn(OH)6/SnO2, was successfully prepared via a facile one-pot in situ hydrothermal method at 220 °C for 24 h. The obtained heterojunctions were characterized via powder X-ray diffraction, Fourier-transform infrared spectroscopy, transmission electron microscopy, and ultraviolet-visible diffuse reflectance spectroscopy. The photocatalytic performance was evaluated for photodegradation of tetracycline solution under ultraviolet irradiation. The initial concentration of tetracycline solution was set to be 20 mg/L. The prepared heterojunctions exhibited superior photocatalytic activity compared with the parent MgSn(OH)6 and SnO2 compounds. Among them, the obtained MgSn(OH)6/SnO2 heterojunction with MgCl2·6H2O:SnCl4·5H2O = 4:5.2 (mmol) displayed the highest photocatalytic performance and the photodegradation efficiency conversion of 91% could be reached after 60 min under ultraviolet irradiation. The prepared heterojunction maintained its performance after four successive cycles of use. Active species trapping experiments demonstrated that holes were the dominant active species. Hydroxyl radicals and superoxide ions had minor effects on the photocatalytic oxidation of tetracycline. Photoelectrochemical measurements were used to investigate the photocatalytic mechanism. The enhancement of photocatalytic activity could be assigned to the formation of a type-II junction photocatalytic system, which was beneficial for efficient transfer and separation of photogenerated electrons and holes. This research provides an in situ growth strategy for the design of highly efficient photocatalysts for environmental restoration.

scholarly journals Selective photocatalytic oxidation of aromatic alcohols to aldehydes with air by magnetic WO3ZnO/Fe3O4. In situ photochemical synthesis of 2-substituted benzimidazoles

RSC Advances ◽  
2020 ◽  
Vol 10 (67) ◽  
pp. 40725-40738
Author(s):  
Bozhi Li ◽  
Reza Tayebee ◽  
Effat Esmaeili ◽  
Mina S. Namaghi ◽  
Behrooz Maleki
Keyword(s):  
Photocatalytic Oxidation ◽  
Photochemical Synthesis ◽  
Magnetic Photocatalyst ◽  
Benzyl Alcohols ◽  
Atmospheric Air ◽  
Aromatic Alcohols

WO3ZnO/Fe3O4 is used as a magnetic photocatalyst in the preparation of 2-substituted benzimidazoles in EtOH at RT. The key feature is the in situ photocatalytic oxidation of benzyl alcohols to benzaldehydes under atmospheric air in the absence of further oxidant.

The influence of plasma of crown discharge and ozone on the rate of photocatalytic oxidation of acetone and benzene vapors

2019 ◽  
Vol 19 (5) ◽  
pp. 391-398
Author(s):  
E. A. Gusachenko ◽  
M. N. Lyulyukin ◽  
D. V. Kozlov
Keyword(s):  
Ir Spectroscopy ◽  
Oxidation Rate ◽  
Photocatalytic Oxidation ◽  
Discharge Plasma ◽  
Considerable Proportion ◽  
Gas Mixture ◽  
In Situ Ir ◽  
Uv Lamp ◽  
In Situ Ir Spectroscopy

The influence of negatively polar plasma of crown discharge on the rate of photocatalytic oxidation (PCO) of vapors of acetone and benzene was investigated by studying dynamics of changes in the composition of gas-air mixture in a 404 L reactor using in-situ IR spectroscopy. Titanium (Hombifine N) was used as the photocatalyst; it was lighted with a UV-lamp at the wavelength λ = 365 nm. The rate of the photocatalytic oxidation of the substrate vapor was compared to the oxidation rate in crown discharge plasma, to the rate of dark oxidation with ozone (side product of the discharge burning), to the rate of photocatalytic oxidation in the presence of ozone, as well as to the rate of the photocatalytic oxidation under medium treatment with the crown discharge plasma. The rate of oxidation of various substrates was shown to be much lower in individual plasma and in ozone-containing atmosphere than in photocatalytic oxidation but application of the crown discharge led to an increase in the rate of photocatalytic oxidation and in the rate of oxidation in ozone-containing atmosphere. Under the action of the discharge, ozone was not accumulated in considerable proportion in the gas mixture but after consumption of 80–90 % of the oxidized substrate. The order of acetone PCO with respect to ozone was determined. It was shown that the action of plasma allowed benzene PCO to be noticeably accelerated due to considerable depression of the photocatalyst deactivation compared to that during individual PCO of benzene.

Simultaneous Photocatalytic Abatement of NO and SO2: Influence of the TiO2 Nature and Mechanistic Insights

2021 ◽  
Vol 02 ◽  
Author(s):  
María D. Hernández-Alonso ◽  
Silvia Suárez ◽  
Fernando Fresno ◽  
Juan M. Coronado ◽  
Benigno Sánchez
Keyword(s):  
Photocatalytic Oxidation ◽  
Surface Composition ◽  
Construction Materials ◽  
Morphological Characteristics ◽  
High Specific Surface Area ◽  
Operating Conditions ◽  
Thermal Methods ◽  
Photo Oxidation ◽  
Vis Spectroscopy

Background: TiO2 is currently being incorporated into several construction materials, such as cement and asphalt, because this photocatalyst can act as a passive system to reduce the concentration of typical urban pollutants like NOx and SO2 under solar illumination. Objective: In order to get further insights on the possible influence of the interaction between common pollutants, the present work investigates the mechanism of NOx photo-oxidation in the presence of SO2 traces over TiO2 samples of different textural and morphological characteristics. Methods: The performance on the photo-oxidation of NOx and SO2 in a dry air stream over different TiO2 samples, both commercial and lab-prepared by hydrothermal and thermal methods, were evaluated by means of FTIR analyses of the gas phase. These materials were characterized by XRD, N2 adsorption isotherms and DR UV-vis spectroscopy. Mechanistic studies were performed by in situ DRIFT under UV irradiation. Results: Photocatalytic tests showed a very efficient removal of the two selected pollutants using most of the TiO2 samples. In the case of SO2, elimination of this molecules is due, not only to photocatalytic oxidation, but also in a significant extent to adsorption. Although in shorter periods no by-products are generated, following irradiation for several hours the production of NO2 progressively increases and reaches 100 % selectivity over some photocatalyst. In situ DRIFTS analyses show the evolution of the surface composition and reveal the formation of the different types of surface nitrates with different symmetry. Under these operating conditions, a limited amount of sulfates are also formed. Conclusions: The presence of low concentration of SO2 does not appear to be detrimental for NO removal. NO2 formation is delayed on the TiO2 samples with high specific surface area, which also tend to be more active. The spectroscopic results confirm the involvement of surface hydroxyls on the formation of adsorbed nitrate species.

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