Molten-Salt-Assisted Synthesis of Bismuth Nanosheets for Long-term Continuous Electrocatalytic Conversion of CO2 to Formate

Two-dimensional (2D) monometallic pnictogens (antimony or Sb, and bismuth or Bi) nanosheets demonstrate potential in a variety of fields, including quantum devices, catalysis, biomedicine and energy, because of their unique physical, chemical, electronic and optical properties. However, the development of general and high-efficiency preparative routes toward high-quality pnictogen nanosheets is challenging. A general method involving a molten-salt-assisted aluminothermic reduction process is reported for the synthesis of Sb and Bi nanosheets in high yields (>90 %). Electrocatalytic CO₂ reduction was investigated on the Bi nanosheets, and high catalytic selectively to formate was demonstrated with a considerable current density at a low overpotential and an impressive stability. Bi nanosheets continuously convert CO₂ into formate in a flow cell operating for one month, with a yield rate of 787.5 mmol cm⁻² h⁻¹. Theoretical results suggest that the edge sites of Bi are far more active than the terrace sites.     

Impact of titanate coupling agent on properties of high density polyethylene composite filled with coal gangue

In this study, surface modification of coal gangue (CG) was performed with titanate coupling agent 201 (isopropyl tri(dioctylpyrophosphate) titanate), and the effects of surface modifier on mechanical properties and thermal stability of high-density polyethylene filled with CG (HDPE/CG) and high-density polyethylene filled with modified CG (HDPE/mCG) composites were investigated. The coupling agent was successfully grafted on CG surface through chemical reaction according to the analyses of Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS), and the coupling agent can effectively enhance the hydrophobicity of surface that was verified by water contact angle beyond 90° of modified CG sample. With the introduction of coupling agent, some enhancements of tensile strength, flexural strength, and impact strength were observed in HDPE/mCG compared with HDPE/CG, due to the improved compatibility between mCG fillers and matrix. The increased storage modulus and decreased loss factor of HDPE/mCG composite further confirm the stronger interface adhesion after modification. Moreover, it is found that titanate coupling agent 201 can improve the thermal stability of HDPE/mCG composite to some extent.     

基于钨(钼)酸铋半导体复合材料的合成及其在光催化降解中的应用

由于全球的工农业的迅速发展,水污染已成为人类所面临的最大危机。基于半导体光催化法是治理水污染的绿色技术之一,能够有效地降解和去除水中的污染物。在众多光催化材料中,金属氧化物半导体由于其具有低毒性、高稳定性和对水溶液中化学腐蚀的较高的抵抗力等优点,而被科学家们广泛地研究和应用。其中,三元组分的金属氧化物因其具有较窄的禁带宽度和可见光响应性质,在光催化降解领域上的能力已经超过其他的金属化合物。本文系统地介绍了两种典型的三元金属氧化物——钨酸铋和钼酸铋,围绕着基于钨酸铋和钼酸铋的复合型催化剂的制备和在光催化降解废水处理领域中的应用以及发展进行了综述,提出了目前关于钨酸铋和钼酸铋的复合材料的设计、机理研究和改性修饰方法中的所存在的主要问题,并对未来的发展趋势进行了展望。     

(NH4)Bi2(IO3)2F5: An Unusual Ammonium‐Containing Metal Iodate Fluoride Showing Strong Second Harmonic Generation Response and Thermochromic Behavior

An ammonium‐containing metal iodate fluoride compound, (NH₄)Bi₂(IO₃)₂F₅, featuring a two‐dimensional double‐layered framework constructed by [BiO₂F₅]^6? and [BiO₄F₄]^9? polyhedra, as well as [IO₃]^? groups, was successfully synthesized. The well‐ordered alignment of these SHG‐active units leads to an extraordinary strong SHG response of 9.2 times that of KDP. Moreover, this compound possesses a large birefringence (Δn=0.0690 at 589.3 nm), a wide energy band gap (E_g=3.88 eV), and a high laser damage threshold (LDT; 40.2×AgGaS₂). In particular, thermochromic behavior was observed for the first time in this type of compound. Such multifunctional crystals will expand the application of nonlinear optical materials.     

Towards Long‐Term Photostability of Nickel Hydroxide/BiVO4 Photoanodes for Oxygen Evolution Catalysts via In Situ Catalyst Tuning

Increasing long‐term photostability of BiVO₄ photoelectrode is an important issue for solar water splitting. The NiOOH oxygen evolution catalyst (OEC) has fast water oxidation kinetics compared to the FeOOH OEC. However, it generally shows a lower photoresponse and poor stability because of the more substantial interface recombination at the NiOOH/BiVO₄ junction. Herein, we utilize a plasma etching approach to reduce both interface/surface recombination at NiOOH/BiVO₄ and NiOOH/electrolyte junctions. Further, adding Fe²⁺ into the borate buffer electrolyte alleviates the active but unstable character of etched‐NiOOH/BiVO₄, leading to an outstanding oxygen evolution over 200 h. The improved charge transfer and photostability can be attributed to the active defects and a mixture of NiOOH/NiO/Ni in OEC induced by plasma etching. Metallic Ni acts as the ion source for the in situ generation of the NiFe OEC over long‐term durability.     

热处理对氧化铋在8μm～14μm波段内的发射率的影响

本文通过设计正交实验,采用不同的热处理工艺对着色颜料氧化铋粉末进行热处理,随后测量样品在8μm～14μm波段的平均法向发射率,并得出优化的热处理工艺路线;对各个影响因素进行的分析表明,温度是热处理过程中影响样品发射率变化的主要因素,并通过XRD、SEM、EDS等多种表征手段,分析了红外发射率变化的内在机理.结果表明,晶格畸变是引起发射率变化的主要因素,而由气体分子吸附引起的表面成分变化对发射率也有一定的影响.     

聚3-甲基噻吩及聚3-己基噻吩修饰钛酸盐纳米管的光电化学性能研究

采用水热法制备了钛酸盐纳米管, 并将钛酸盐纳米管制备成纳米结构电极进行光电化学研究. 钛酸盐纳米管产生阳极光电流, 具有n-型半导体特性. 结果表明, 聚3-甲基噻吩[poly(3-methylthiophene), PMeT]、聚3-己基噻吩[poly(3-hexylthiophene), P3HT]修饰钛酸盐纳米管后产生的光电流均较纯钛酸盐纳米管的光电流高, 且使产生光电流的波长向长波区移动. 钛酸盐纳米管/PMeT、钛酸盐纳米管/P3HT的光电转换效率分别达11.40%, 0.91%(未校正光子损失). 钛酸盐纳米管/PMeT的光电转换效率较钛酸盐纳米管/P3HT的光电转换效率高10.5%. 钛酸盐纳米管/PMeT、钛酸盐纳米管/P3HT中存在p-n异质结, 在一定条件下p-n异质结的存在有利于光生电子/空穴的分离.     

钛酸纳米管和钛酸纳米薄片相变规律比较

TiO2与浓NaOH溶液反应可制得组成是Na2-xHxTi2O4（OH）2,0≤X≤2的纳米管。X随后处理时溶液的pH值的不同而不同,当X=2时即为钛酸纳米管。本文在考察热处理温度对钛酸纳米管和钛酸纳米薄片相变的影响时,发现它们的相变规律几乎完全相同。本文通过TEM、XRD、Raman及FT-IR光谱等技术对合成的钛酸纳米管和钛酸纳米薄片随焙烧温度的相变规律、晶粒形状及结晶程度等性质进行了比较和讨论。     

B2O3掺杂对Ba0.6Sr0.4TiO3/MgO陶瓷介电性能的影响

采用XRD和SEM对B2O3掺杂Ba0.6Sr0.4TiO3/MgO(简称为BSTM)陶瓷致密化行为和介电性能进行了研究。结果表明:掺杂适量B2O3可明显降低BSTM陶瓷的烧结温度,在1480℃时即可烧结致密化,比未掺杂的BSTM陶瓷烧结温度降低70℃;掺杂量不同,则B2O3在陶瓷体中的存在形式不同,引起其介电性能相应变化;1480℃下烧结,B2O3掺杂量为0.8%(质量分数)时,10kHz下测得试样的εr为138,tanδ为0.0034,εr可调率达12.6%(3MV/m),性能有所提高。     

苯并噁嗪/钛酸钡复合材料介电性能的研究

通过共混法制备了苯并噁嗪/钛酸钡复合材料,探讨了钛酸钡粒径和填充量对复合材料介电性的影响。当?(BaTiO3)=50%时,复合材料介电常数εr达54、介质损耗tanδ为0.027、体积电阻率ρv大于1011?·m、击穿电压Vb大于8×103V/mm的高εr低tanδ绝缘材料。并将其应用于制备内嵌式电容器用玻璃布复合层压板。