Transparent p‐NiO/n‐ZnO diodes used in circuit rectifiers

We report on the fabrication of a transparent photostable cell circuit composed of drive and resistor diodes which are face‐to‐face connected to each other with different device area. The diodes consisted of e‐beam evaporated p‐NiO on sputter‐deposited n‐ZnO for p/n diode formation on indium‐tin‐oxide glass. Our transparent diodes show photostable rectifying behavior, about 10³ on/off current ratio and even dynamic rectification at a maximum frequency of 100 Hz AC input signal in ambient light. The noticeable photo‐responsivity of the circuit was obtained only under ultraviolet (UV) light. We conclude that our transparent diode circuit is promising in enriching the field of transparent device electronics. (© 2012 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

双通氧化铝模板制备及其填充NiO的研究

制备具有双通纳米孔道填充过渡金属氧化物NiO的氧化铝模板,初步表征其电化学性质.结果发现,该氧化铝模板的纳米孔道结构均匀,孔道直径约为 50nm,所填充的纳米NiO层厚度相对均匀,并具有较好的循环稳定性.     

静电纺丝法制备NiO纳米纤维及其表征

纳米级NiO因具有优良的催化和热敏等性能而被广泛用于催化剂^[1]、电池电极^[2,3]、光电转化材料^[4～6]、电化学电容器^[7～8]等诸多方面.迄今,已成功地制备出N iO的纳米颗粒^[9]、纳米线^[10]及纳米薄膜^[11],但是对于具有准一维结构的NiO纳米纤维的制备及性能研究尚未见报道.     

Hydrodesulfurization of Thiophene on Ni,Mo-supported MCM-41 Catalysts

ＩｎｔｒｏｄｕｃｔｉｏｎＴｈｅｒｅｃｅｎｔｄｉｓｃｏｖｅｒｙｏｆｎｏｖｅｌｅｘｔｒａｌａｒｇｅｍｅｓｏｐｏｒｏｕｓＭＣＭ－４１ｍｏｌｅｃｕｌａｒｓｉｅｖｅｓ［１，２］ｆｉｌｓｔｈｅｇａｐｂｅｔｗｅｅｎｍｉｃｒｏｐｏｒｏｕｓａｎｄｍａｃｒｏｐｏｒｏｕｓ...     

Structural,optical and photocatalytic applications of biosynthesized NiO nanocrystals

NiO is one of the most important candidates for semiconductors metal oxide nanocrystals by the arrangement of photocatalytic application. However, the photocatalytic performance of biosynthesized nanocrystals using Aspalathus linearis (Burm.f.) R. Dahlgren has not been investigated yet. In this contribution, we synthesize α-Ni(OH)₂ using an A. linearis. A heat treatment of the α-Ni(OH)₂ is carried out at 300–400°C for 2?h at normal air yields. Furthermore, we have characterized the structural, optical and photocatalytic activity of the samples. The optical results indicate that biosynthesized nanocrystals exhibit UV–visible light absorption and a narrow range distribution of intense green light (518.95?nm) emission, which decreases significantly as annealing temperature increases. The bandgap energies of the sample annealed at 300–400°C shift to lower photon energy, compared to bulk NiO (～ 4?eV). Moreover, the photocatalytic experimental results reveal that NiO nanocrystals enable color switching of methylene blue.     

镍含量对NiO/SiO2气凝胶性能的影响

A series of NiO/SiO₂ aerogel catalysts were prepared by sol-gel method. The effects of the nickel content on the structure and existing forms of NiO/SiO₂ aerogel catalysts were investigated by using XRD, TPR and FT-IR. The results showed that there were interactions between NiO and SiO₂. But as nickel content increased, the in-teraction decreased. The nickel oxide in the catalysts appeared in different forms as nickel content was changed. When the content was less than 13%, Ni(Ⅱ) entered into the SiO₂ structure completely and it became clusters after calcining. If the content altered from 20% to 50%, NiO existed as both microcrystal and clusters, the later spices was dominating. However, when the content increased to 70%, microcrystal became the primary components.     

The role of thermal analysis in optimization of the electrochromic effect of nickel oxide thin films, prepared by the sol–gel method: Part II

Thin films and the corresponding xerogels were prepared from nickel acetate precursor using the sol–gel dip-coating technique. The differences in thermal stability of the two forms of samples were studied by dynamic and isothermal thermogravimetry. For thin films, the onset decomposition temperature of acetate groups was 230 °C and for the xerogel 250 °C. During thermal decomposition, the formation of nanosized nickel oxide took place. Carbonate ions, which were formed during thermal decompostion of acetate groups, remained either free or bidentately coordinated to nickel. In situ monochromatic optical transmittance changes showed that an optical stability up to the 100th cycle was already achieved for films heated for 15 min at the isothermal temperature (thermal decompositon 25%). Comparison of the results obtained for nickel sulfate (Part I) and nickel acetate precursors shows that at least two parameters, the precursor used and the degree of thermal treatment, have considerable influence on the thermal stability of the thin film and also on its electrochromic response during the cycling process.     

二维层状NiO/g-C3N4复合材料在无铁光电类芬顿体系中有效去除环丙沙星的研究

Excessive use of ciprofloxacin (CIP) has proven to be a significant threat to the ecological environment. In this work, a novel Fe-free photo-electro-Fenton system was designed for the degradation of CIP in water. The NiO/g-C₃N₄ composites were synthesized by a simple solvothermal method. The crystalline phases and chemical compositions of the different catalysts were determined via X-ray diffraction (XRD) analysis. Fourier transform infrared (FT-IR) spectroscopy further confirmed the molecular structures of the different composites. The results proved the successful synthesis of NiO/g-C₃N₄ composites. The morphology of the material was obtained using scanning electron microscopy (SEM), which showed that the structure of the optimal NiO/g-C₃N₄-60% was two-dimensional and flower-like. The transmission electron microscopy (TEM) analysis further proved that the NiO/g-C₃N₄-60% possessed a layered structure. Owing to the layered structure, the NiO/g-C₃N₄-60% boasts of a large specific surface area and abundant active sites, which were beneficial for the transmission of electrons and oxidation of CIP. Furthermore, it was evident from the X-ray photoelectron spectroscopy (XPS) analysis that the Ni²⁺ and Ni³⁺ coexisted, and there was low coordination oxygen with defects in the NiO/g-C₃N₄-60% composite. The electron paramagnetic resonance (EPR) spectrum also proved the existence of oxygen vacancies, which not only facilitated the activation of H₂O₂, but also promoted the formation of stable mixed valence states of metal ions. UV-vis diffuse reflection spectrum (UV-Vis DRS), photoluminescence (PL), and electrochemical tests showed that NiO/g-C₃N₄-60% exhibited the strongest light absorption capacity, lowest charge transfer resistance, and fastest charge separation efficiency, which was beneficial for the generation of active species and the rapid degradation of CIP. Therefore, the flower-like NiO/g-C₃N₄-60% composites exhibited photoelectric synergy in the photo-electro-Fenton process. They not only effectively decomposed the H₂O₂ produced in the electro-Fenton process into ·OH by the conversion of Ni³⁺/Ni²⁺, but also generated photogenerated electrons and holes to promote the production of ·OH, ·O₂^–, and h⁺ under light irradiation to improve the degradation efficiency of CIP. When the optimal NiO/g-C₃N₄-60% served as a catalyst in the photo-electro-Fenton system, the degradation efficiency of CIP reached approximately 100% in 90 min and the mineralization efficiency reached 82.0% in 120 min. In addition, compared with the traditional Fenton system (the optimal pH value of which is 2.8–3.5), the novel photo-electro-Fenton system possessed a wider range of pH, with a final CIP degradation efficiency of 78.8% at a pH value of 6. The NiO/g-C₃N₄-60% also demonstrated excellent structural stability in the photo-electro-Fenton system. After five consecutive cycles, the degradation efficiency was maintained at 96.3%. Based on the results of high-performance liquid chromatography-mass spectrometry (HPLC-MS), two possible pathways for CIP degradation were proposed. This study provides a theoretical basis for the rapid degradation of antibiotics in wastewater.      

Electrospinning preparation of NiO/ZnO composite nanofibers for photodegradation of binary mixture of rhodamine B and methylene blue in aqueous solution: Central composite optimization

One‐dimensional nanofiber of p‐type NiO/n‐type ZnO heterojunctions with various molar ratios of Ni to Zn at different calcination temperatures were successfully synthesized using the electrospinning method, and they were fully characterized. The photocatalysts thus obtained were applied in aqueous solutions for rhodamine B (RDB) and methylene blue (MB) degradation. The p–n heterojunctions built among the cubic structure NiO and hexagonal structure ZnO in the composite nanofiber are responsible for generation of electrons and holes and subsequently superoxide and hydroxyl radical production by carriers which lead to degradation of the dyes in solution. The composite nanofibers (ZnNi1) calcined at 550 °C for 3 h showed the highest photocatalytic activity for degradation of the dyes in aqueous solution. The optimum values were found to be 180 min, 7.0, 1 g l^?1 and 3.0 and 3.0 mg l^?1 for irradiation time, pH, photocatalyst dosage and initial concentration of RDB and MB, respectively. For these optimum conditions, the photocatalytic degradation of RDB and MB was found to be 99.37 and 98.44%, respectively. The maximum photodegradation of RDB and MB using ZnNi1 was 59.41 and 65.43%, respectively. First‐order kinetics based on the Langmuir–Hinshelwood model successfully fitted the experimental data.     

Electrosynthesis of azopyrazoles via the oxidation of N-alkylaminopyrazoles on a NiO(OH) anode in aqueous alkali – A green method for N-N homocoupling

A nickel oxyhydroxide [NiO(OH)] anode was exploited to develop a new synthetic route for the electrocatalytic N-N homocoupling of N-alkylaminopyrazoles in an alkaline aqueous medium. The advantages of this green electrochemical methodology include low cost, atom economy and high yields.