DFT Study on Regulating the Electronic Structure and CO2 Reduction Reaction in BiOBr/Sulphur-Doped G-C3N4 S-Scheme Heterojunctions

Photocatalytic CO2 reduction is a promising method to mitigate the greenhouse effect and energy shortage problem. Development of effective photocatalysts is vital in achieving high photocatalytic activity. Herein, the S-scheme heterojunctions composed by BiOBr and g-C3N4 with or without S doping are thoroughly investigated for CO2 reduction by density functional theory (DFT) calculation. Work function and charge density difference demonstrate the existence of a built-in electric field in the system, which contributes to the separation of photogenerated electron-hole pairs. Enhanced strength of a built-in electric field is revealed by analysis of Bader charge and electric field intensity. The results indicate that S doping can tailor the electronic structures and thus improve the photocatalytic activity. According to the change in absorption coefficient, system doping can also endow the heterojunction with increased visible light absorption. The in-depth investigation indicates that the superior CO2 reduction activity is ascribed to low rate-determining energy. And both of the heterojunctions are inclined to generate CH3OH rather than CH4. Furthermore, S doping can further reduce the energy from 1.23 to 0.44 eV, indicating S doping is predicted to be an efficient photocatalyst for reducing CO2 into CH3OH. Therefore, this paper provides a theoretical basis for designing appropriate catalysts through element doping and heterojunction construction

Luminescent nanostructured materials for use in electrogenerated chemiluminescence

A nanostructured particulate material, which includes a redox active luminescent organic and/or ionic compound, is provided herein. The nanostructured particulate material may be used for determining the presence of an analyte of interest in a sample by detecting the emitted electromagnetic radiation generated by exposing a reagent mixture, which includes the nanostructured material and the target analyte, to chemical or electrochemical energy.Board of Regents, University of Texas Syste

Effects of Glyphosate-Resistant Genetically Modified Soybean on Blood Biochemical Indexes, Hepatopancreatic Antioxidant Capacity and Tissue Morphology of Cyprinus carpio

The juvenile carps (Cyprinus carpio) were fed diets with four protein sources (15% and 30% glyphosate-resistant genetically modified (GM) named GM 15 and GM 30, respectively, and 15% and 30% non-genetically modified (NGM) soybean named NGM 15 and NGM 30) for 180 days. Results showed that alkaline phosphatase (ALP) activity for the GM30 group was significantly lower than that of the NGM30 group. The activity of glutathione peroxidase (GSH-Px) in the hepatopancreas of carp for the GM30 group was significantly higher than that of the NGM15 group (P0.05). This study indicates that it may aggravate the damage degree of intestinal epithelial cells of carp and more easily cause liver cell damage in the short term when the amount of GM soybean in the feeds was 30%. Therefore, higher glyphosate-resistant GM soybean may have adverse effects on the carp's serum, intestinal, and hepatopancreas and considerably reduce the hepatopancreatic carp's antioxidant capacity

Preparation of fluorine-doped TiO2 photocatalysts with controlled crystalline structure

Recommended by M. Sabry Abdel-Mottaleb Nanocrystalline F-doped TiO 2 powders were prepared by sol-gel route. The thermal behavior of the powders was recorded by DTA/TG technique. The crystalline phase of the fluorinated TiO 2 powders was determined by X-ray diffraction technique. It was demonstrated that F-doping using CF 3 COOH favors the formation of rutile along with anatase phase even at low temperature. Moreover, the rutile's phase content increases with the increase of the quantity of the fluorine precursor in the starting solution. The surface area of the powders and the pore size distribution were studied by N 2 adsorption-desorption using BET and BJH methods. X-ray photoelectron spectroscopy (XPS) revealed that the fluorine is presented in the TiO 2 powders mainly as metal fluoride in quantities ∼16 at %. The F-doped TiO 2 showed a red-shift absorption in UV-vis region which was attributed to the increased content of rutile phase in the powders. The powders exhibited enhanced photocatalytic activity in decomposition of acetone

PdCu nanoalloy decorated photocatalysts for efficient and selective oxidative coupling of methane in flow reactors

Methane activation by photocatalysis is one of the promising sustainable technologies for chemical synthesis. However, the current efficiency and stability of the process are moderate. Herein, a PdCu nanoalloy (~2.3 nm) was decorated on TiO2, which works for the efficient, stable, and selective photocatalytic oxidative coupling of methane at room temperature. A high methane conversion rate of 2480 μmol g-1 h-1 to C2 with an apparent quantum efficiency of ~8.4% has been achieved. More importantly, the photocatalyst exhibits the turnover frequency and turnover number of 116 h-1 and 12,642 with respect to PdCu, representing a record among all the photocatalytic processes (λ > 300 nm) operated at room temperature, together with a long stability of over 112 hours. The nanoalloy works as a hole acceptor, in which Pd softens and weakens C-H bond in methane and Cu decreases the adsorption energy of C2 products, leading to the high efficiency and long-time stability

Solvothermal synthesis and photocatalytic performance of Mg2+-doped anatase nanocrystals with exposed {0 0 1} facets

The photocatalytic activity of TiO2 and magnesium doped TiO 2 nanocrystals in dopant range of 2-6.2 at%, was studied. The doped and undoped nanocrystals with exposed {0 0 1} crystal facets were synthesized by a solvothermal method. Several studies have shown that the (0 0 1) surface of the TiO2 anatase crystal is more reactive than the thermodynamically stable (1 0 1) surface. The crystal structure as well as the shape of the TiO2 and Mg2+/TiO2 anatase nanoparticles were determined using two different techniques, such as X-ray powder diffraction (XRD) and transmission electron microscopy (TEM), which both lead to the agreeable conclusion that the nanocrystals are in the form of plates. Chemical analysis of the photocatalyst was carried out with X-ray photoelectron spectroscopy (XPS) and showed the presence of magnesium ions in the TiO 2 nanoplates. UV-vis diffuse reflectance spectroscopy (DRS) showed that there is an adsorption shift for doped TiO2 to visible light region. The photocalaytic efficiency of the synthesized catalysts was investigated by the photocatalytic oxidation of the gaseous nitric oxide (NO) and decomposition of the gaseous acetaldehyde (CH3CHO) under UV irradiation. It was demonstrated that the low Mg2+ doped catalysts exhibited higher photocatalytic activity than the pure TiO2. The optimal concentration of dopant that is beneficial for the photocatalytic activity was studied. © 2013 Elsevier B.V