Weighted Estimates for Iterated Commutators of Riesz Potential on Homogeneous Groups

In this paper, we study the two weight commutators theorem of Riesz potential on an arbitrary homogeneous group H of dimension N. Moreover, in accordance with the results in the Euclidean space, we acquire the quantitative weighted bound on homogeneous group

In Situ Synthesis of Ti:Fe₂O₃/Cu₂O p-n Junction for Highly Efficient Photogenerated Carriers Separation

High photoelectrochemical water oxidation efficiency can be achieved through an efficient photogenerated holes transfer pathway. Constructing a photoanode semiconductor heterojunction with close interface contact is an effective tactic to improve the efficiency of photogenerated carrier separation. Here, we reported a novel photoanode p-n junction of Ti:Fe2O3/Cu2O (n-Ti:Fe2O3 and p-Cu2O), Cu2O being obtained by in situ reduction in CuAl-LDH (layered double hydroxides). The Ti:Fe2O3/Cu2O photoanode exhibits a high photocurrent density reaching 1.35 mA/cm2 at 1.23 V vs. RHE is about 1.67 and 50 times higher than the Ti:Fe2O3 and α-Fe2O3 photoanode, respectively. The enhanced PEC activity for the n-Ti:Fe2O3/p-Cu2O photoelectrode is due to the remarkable surface charge separation efficiency (ηsurface 85%) and bulk charge separation efficiency (ηbulk 72%) formed by the p-n junction and the tight interface contact formed by in situ reduction. Moreover, as a cocatalyst, CuAl-LDH can protect the Ti:Fe2O3/Cu2O photoanode and improve its stability to a certain extent. This study provides insight into the manufacturing potential of in situ reduction layered double hydroxides semiconductor for designing highly active photoanodes in the field of photoelectrochemical water oxidation

Carbon and nitrogen co-doped TiO2with enhanced visible-light photocatalytic activity

International audienceTo utilize visible light more efficiently in photocatalytic reactions, carbon-doped TiO2 (C?TiO2), nitrogen-doped TiO2 (N?TiO2), and carbon and nitrogen co-doped TiO2 (C?N?TiO2) nanoparticles with different nitrogen and carbon contents were prepared by a sol?gel method and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and UV?vis spectroscopy. XRD results showed that the doping of C and N atoms could suppress the crystal growth of TiO2, and the effect of C doping was more pronounced than that of N doping. XPS, UV?vis spectroscopy, and lattice parameter analysis revealed that N atoms could incorporate into the lattice of anatase through substituting the sites of oxygen atoms, while most C atoms could form a mixed layer of deposited active carbon and complex carbonate species at the surface of TiO2 nanoparticles. The photocatalytic activities of obtained C?TiO2, N?TiO2, and C?N?TiO2 samples with different C and N contents were evaluated by methylene blue degradation under visible light irradiation. It was found that C?N?TiO2 nanomaterials exhibited the highest photocatalytic activity, which could be assigned to the synergistic effect of doped C and N atoms

Design of lateral and vertical Bi4O5I2/BiOCl heterojunctions with different charge migration pathway for efficient photoredox activity

As 2D heterojunction photocatalysts, lateral heterojunctions (LHs) formed based on chemical bonding generally exhibit much higher photocarrier separation efficiency than vertical heterojunctions (VHs) formed by van der Waals bonds. However, little is known about the different detailed interfacial structures and photocarrier separation mechanisms of the two heterojunctions. Herein, 2D BiOCl and Bi4O5I2 were selected as model building blocks to construct BiOCl/Bi4O5I2 VHs and LHs. The LHs with direct charge carrier transport channels show stronger interfacial electric field and higher charge transfer efficiency than the VHs. The photogenerated charge carrier migration pathway in the LHs follows a Z-scheme model, while the VHs fits a type II model. As a result, the BiOCl/Bi4O5I2 LHs exhibited higher redox performance than the VHs, which is 1.55, 1.56 and 2.1 times better for H2 production, Cr(VI) photoreduction and phenol photodegradation, respectively. This study demonstrates a new approach to constructing highly efficient facet-dependent 2D heterojunction photocatalysts

Influence of Defects on the Photocatalytic Activity of ZnO

The influence of defects on the photoactivity of ZnO has been revealed. The defects can be formed via ball-milling treatment, and part of the defects can be repaired via annealing treatment. The photocatalytic activity of the ZnO sharply decreased as the ball-milling speed and milling time increased. After the annealing treatment, the photocatalytic activity recovered partly but could not return to the activity of the pristine ZnO. The bulk defects such as oxygen vacancies (V_O), zinc vacancies (V_Zn) and a lot of nonradiative defects were formed after the milling treatment. The annealing treatment can only repair part of the bulk defects and nonradiative defects. Thus, only part of the photoactivity was recovered. The species trapping experiments showed that the introduction of the bulk defects did not change the photocatalytic mechanism. The main oxidative species for the pristine ZnO, the milled ZnO, and the annealed ZnO are photogenerated holes and hydroxyl radicals

Selective Capture of Iodide from Solutions by Microrosette-like δ‑Bi₂O₃

Radioactive iodine isotopes that are produced in nuclear power plants and used in medical research institutes could be a serious threat to the health of many people if accidentally released to the environment because the thyroid gland can absorb and concentrate them from a liquid. For this reason, uptake of iodide anions was investigated on microrosette-like δ-Bi₂O₃ (MR-δ-Bi₂O₃). The MR-δ-Bi₂O₃ adsorbent showed a very high uptake capacity of 1.44 mmol g^–1 by forming insoluble Bi₄I₂O₅ phase. The MR-δ-Bi₂O₃ also displayed fast uptake kinetics and could be easily separated from a liquid after use because of its novel morphology. In addition, the adsorbent showed excellent selectivity for I^– anions in the presence of large concentrations of competitive anions such as Cl^– and CO₃^2–, and could work in a wide pH range of 4–11. This study led to a new and highly efficient Bi-based adsorbent for iodide capture from solutions

Henoch–Schönlein purpura nephritis complicated by reversible posterior leukoencephalopathy syndrome

The original publication is available at www.springerlink.com.ArticleCLINICAL RHEUMATOLOGY. 26(10): 1761-1763 (2007)journal articl