Efficient BiVO4 Photoanodes by Postsynthetic Treatment: Remarkable Improvements in Photoelectrochemical Performance from Facile Borate Modification

Water‐splitting photoanodes based on semiconductor materials typically require a dopant in the structure and co‐catalysts on the surface to overcome the problems of charge recombination and high catalytic barrier. Unlike these conventional strategies, a simple treatment is reported that involves soaking a sample of pristine BiVO₄ in a borate buffer solution. This modifies the catalytic local environment of BiVO₄ by the introduction of a borate moiety at the molecular level. The self‐anchored borate plays the role of a passivator in reducing the surface charge recombination as well as that of a ligand in modifying the catalytic site to facilitate faster water oxidation. The modified BiVO₄ photoanode, without typical doping or catalyst modification, achieved a photocurrent density of 3.5 mA cm^?2 at 1.23 V and a cathodically shifted onset potential of 250 mV. This work provides an extremely simple method to improve the intrinsic photoelectrochemical performance of BiVO₄ photoanodes.     

Catalytic Oxidation of Trichloroethylene over RuO2 Supported on Ceria-zirconia Mixed Oxide

Ru/Ce-Zr catalysts were prepared by impregnation of Ru on the hydrothermally synthesized Ce-Zr mixed oxide with different molar ratio of Ce/Zr.The resultant products were systematically characterized by inductively coupled plasma(ICP),X-ray diffraction(XRD),scanning electron microscopy(SEM)/energy dispersive spectrometry(EDS),H2-temperature programmed reduction(H2-TPR),NH3-temperature programmed desorption(NH3-TPD)and X-ray photoelectron spectroscopy(XPS).It was proved by H2-TPR and NH3-TPD that the introduction of Ru can improve the activity of oxygen of catalysts and the presence of Zr contributes to the increments of acid properties of catalysts.When the molar ratio of Ce-Zr was 8:4,the quantity of Ru was 0.9%(mass ratio),and the calcined temperature of catalysts was at 400℃,the removal rate of 90% for trichloroethylene(TCE)was reached at 250℃ for 5360 mg/m^3 TCE and the stability of the catalysts was investigated under the condition.The results showed that the high removal rate can be maintained for at least 90 h,which is promising for industrial application.     

Direct observation of whispering gallery mode polaritons and their dispersion in a ZnO tapered microcavity

We report direct observation of the strong exciton-photon coupling in a ZnO tapered whispering gallery (WG) microcavity at room temperature. By scanning excitations along the tapered arm of the ZnO tetrapod using a micro-photoluminescence spectrometer with different polarizations, we observed a transition from the pure WG optical modes in the weak interaction regime to the excitonic polariton in the strong coupling regime. The experimental observations are well described by using the plane wave model including the excitonic polariton dispersion relation. This provides a direct mapping of the polariton dispersion, and thus a comprehensive picture for coupling of different excitons with differently polarized WG modes.     

Sodium Carbazolide and Derivatives as Solid-State Electrolytes for Sodium-Ion Batteries

Replacing widely used organic liquid electrolytes with solid-state electrolytes (SSEs) could effectively solve the safety issues in sodium-ion batteries. Efforts on seeking novel solid-state electrolytes have been continued for decades. However, issues about SSEs still exist, such as low ionic conductivity at ambient temperature, difficulty in manufacturing, low electrochemical stability, poor compatibility with electrodes, etc. Here, sodium carbazolide (Na-CZ) and its THF-coordinated derivatives are rationally fabricated as Na⁺ conductors, and two of their crystal structures are successfully solved. Among these materials, THF-coordinated complexes exhibit fast Na⁺ conductivities, i.e., 1.20×10⁻⁴ S cm⁻¹ and 1.95×10⁻³ S cm⁻¹ at 90 °C for Na-CZ-1THF and Na-CZ-2THF, respectively, which are among the top Na⁺ conductors under the same condition. Furthermore, stable Na plating/stripping is observed even over 400 h cycling, showing outstanding interfacial stability and compatibility against Na electrode. More advantages such as ease of synthesis, low-cost, and cold pressing for molding can be obtained. In situ NMR results revealed that the evaporation of THF may play an essential role in the Na⁺ migration, where the movement of THF creates defects/vacancies and facilitates the migration of Na⁺.     

天然沸石及其在三废治理方面的应用

本文简单介绍了天然沸石矿物的基本物理化学性能及其在环境保护中的应用。     

吸收光谱法研究新型双钼配合物{Mo[S2CN(C2H5)2 4}{MOCl6)}的结构

双钼配合物〔Mo(DTC)₄〕〔MoCl₆〕(其中DTC=S₂CN(C₂H₅)₂)由于它在一个分子中同时包含两个处于不同配位环境中的、表观氧化态都是正五价的钼,即:一个Mo⁵⁺与四个DTC配体构成配位阳离子〔Mo(DTC)₄〕⁺;另一个Mo⁵⁺与氯离子配体构成配位阴离子〔MoCl₆〕^-而独具特色。本文首次发表了它的红外和紫外-可见吸收光谱数据,并通过初步的光谱分析,确定了上述配合物的结构特征。     

Theoretical studies on the structures and isomerization of the LiSiF3 system

Various possible isomers of LiSiF₃ system and isomerization between them have been studied at G2(MP2) level usingab initio calculations. The relative energies of four minimum points on the potential energy surface are-128.6,-194.3,-12.7 and-122.8 kJ/mol (taking the sum of the energies of LiF and SiF₂ as zero). The structural energy of the four-membered ring that contains three F-Si-F-Li four-membered rings with C_3v symmetry is the lowest. The highest potential barrier for the isomerization of the remaining three- or four-membered structure is 12.5 kJ/ mol. Project supported by the National Natural Science Foundation of China (Grant No. 29673026).     

微波辅助提取-液相色谱-氢化物发生-原子荧光光谱法分析沉积物中砷的形态

采用微波辅助提取-液相色谱-氢化物发生-原子荧光光谱法(LC-HG-AFS)联用技术分析了太湖沉积物中砷的形态[亚砷酸(As(III))、二甲基砷酸钠(DMA)、一甲基砷酸二钠(MMA)和砷酸As(V)]。测得沉积物中以无机砷为主,且以As(V)居多。选定以1mol/L的磷酸和0.1mol/L抗坏血酸为提取液,在微波辅助萃取(功率为60W,时间12min)下,萃取率达79.84%～91.57%,回收率在94.78%～107.6%之间。4种砷的形态在0～160μg/L之间时线性良好,检测限为0.6～2.3μg/L,相对标准偏差RSD为1.62%～2.20%。方法具有简便、快速、灵敏的特点。     

用示波器测电池的电动势和内电阻

本介绍了一种新的测量电源电动势的方法,即用示波器测电池的电动势和内电阻。     

SPEEK/PES-C、SPEEK/SPES-C共混质子交换膜研究

通过在磺化聚醚醚酮(SPEEK,DS=61.68%)中分别混入酚酞型聚醚砜(PES-C)、磺化酚酞型聚醚砜(SPES-C,DS=53.7%)制备出SPEEK/PES-C、SPEEK/SPES-C共混质子交换膜.结果表明,共混的两种聚合物之间均具有较好的相容性.PES-C、SPES-C的混入能有效降低膜的溶胀及甲醇透过,且随着共混量的增加,这种作用越趋明显.纯SPEEK膜在75℃左右溶解,而SPEEK/PES-C(30wt%)、SPEEK/SPES-C(30wt%)共混膜在80℃时溶胀度仅为22.5%、26.32%.在室温至80℃范围内,纯SPEEK及共混膜的甲醇透过系数都在10-7cm2.s-1数量级上,远小于Nafion115膜.在饱和湿度下,温度大于90℃时,SPEEK/PES-C(20wt%)共混膜电导率超过Nafion115膜;温度大于110℃时,SPEEK/SPES-C(30wt%)共混膜电导率与Nafion115膜相当,达到0.11S.cm-1.高电导率,低透醇系数以及明显提高了的可使用温度表明该类共混膜有望在DMFC中使用.