Green preparation of vanadium carbide through one-step molten salt electrolysis

Vanadium carbide (VC) as excellent ceramic and functional material is usually prepared by carbothermal reduction of V₂O₅ which must be extracted from a typical V slag by complex processes. Pollutants, such as ammonia-nitrogen wastewater, NH₃ and CO₂ are inevitably discharged. A novel and green method for VC preparation was proposed by one-step co-electrolysis of soluble NaVO₃ and CO₂ in molten salt. It was found that VC with high purity was easily obtained by reducing electrolysis temperature and CO₂ flow rate to 600 °C and 10 mL min⁻¹ at 3.0 V. Besides VC with particles and layered stacking structure in products, a small amount of carbon and oxygen elements existed. The atomic percentage contents of C, V, and O elements in VC were about 50.0%, 44.5% and 3.8%, respectively. During electrolysis, CO₃²⁻ and VO₃⁻ was reduced at about −0.55 V (vs. Ag/AgCl) and −1.38 V (vs. Ag/AgCl), respectively. CO₃²⁻ ions were more easily reduced than VO₃⁻, and was firstly reduced to CO₂²⁻ and then converted to C. Then, VC was prepared by two routes from CO₂ and NaVO₃. One route is that VO₃⁻ ions are firstly electroreduced to VO₂⁻ ions and then are further electroreduced to VC with C. Another route is that VO₃⁻ ions are electroreduced to V which in-situ reacted with C to VC. Both VO₃⁻ and CO₃²⁻ ions are electroreduced by two-step process. In final, VC is in-situ deposited on cathode. It provides a novel and green way to prepare VC and also achieves the high value-added utilization of vanadium slag and CO₂.     

不同盐沼湿地类型脱氮除磷效能及影响因素分析

采用沉水植物表面流湿地(沉水组)、挺水植物表面流湿地(挺水组)和浮床湿地(浮床组)3种盐沼湿地对长江口近岸低污染水体进行脱氮除磷效能的研究。结果表明,HRT为3 d时,水组、挺水组、浮床组对NO3^--N的去除率在高温时段分别为79.9%±13.2%、71.8%±15.2%、77.2%±13.2%,中温时段分别为39.4%±13.7%、31.5%±8.5%、18.4%±16.6%,低温时段分别为15.6%±14.6%、19.7%±8.6%、2.%5±8.6%。沉水组和挺水组对TP的去除率受温度影响较小,分别为66.4%±32.4%、55.5%±29.4%;而浮床组除磷效果受温度影响较大。当HRT缩短为1.5 d时,3组湿地系统在高温时段仍可达到相近的脱氮除磷效果,在中低温时段脱氮除磷效果都有不同程度的下降。     

Stem Photosynthesis—A Key Element of Grass Pea (Lathyrus sativus L.) Acclimatisation to Salinity

Grass pea (Lathyrus sativus) is a leguminous plant of outstanding tolerance to abiotic stress. The aim of the presented study was to describe the mechanism of grass pea (Lathyrus sativus L.) photosynthetic apparatus acclimatisation strategies to salinity stress. The seedlings were cultivated in a hydroponic system in media containing various concentrations of NaCl (0, 50, and 100 mM), imitating none, moderate, and severe salinity, respectively, for three weeks. In order to characterise the function and structure of the photosynthetic apparatus, Chl a fluorescence, gas exchange measurements, proteome analysis, and Fourier-transform infrared spectroscopy (FT-IR) analysis were done inter alia. Significant differences in the response of the leaf and stem photosynthetic apparatus to severe salt stress were observed. Leaves became the place of harmful ion (Na⁺) accumulation, and the efficiency of their carboxylation decreased sharply. In turn, in stems, the reconstruction of the photosynthetic apparatus (antenna and photosystem complexes) activated alternative electron transport pathways, leading to effective ATP synthesis, which is required for the efficient translocation of Na⁺ to leaves. These changes enabled efficient stem carboxylation and made them the main source of assimilates. The observed changes indicate the high plasticity of grass pea photosynthetic apparatus, providing an effective mechanism of tolerance to salinity stress.     

A Highly Sensitive,Reversible, and Bidirectional Humidity Actuator by Calcium Carbonate Ionic Oligomers Incorporated Poly(Vinylidene Fluoride)

Sensitivity and multi-directional motivation are major two factors for developing optimized humidity-response materials, which are promising for sensing, energy production, etc. Organic functional groups are commonly used as the water sensitive units through hydrogen bond interactions with water molecules in actuators. The multi-coordination ability of inorganic ions implies that the inorganic ionic compounds are potentially superior water sensitive units. However, the particle forms of inorganic ionic compounds produced by classical nucleation limit the number of exposed ions to interact with water. Recent progress on the inorganic ionic oligomers has broken through the limitation of classical nucleation, and realized the molecular-scaled incorporation of inorganic ionic compounds into an organic matrix. Here, the incorporation of hydrophilic calcium carbonate ionic oligomers into hydrophobic poly(vinylidene fluoride) (PVDF) is demonstrated. The ultra-small calcium carbonate oligomers within a PVDF film endow it with an ultra-sensitive, reversible, and bidirectional response. The motivation ability is superior to other bidirectional humidity-actuators at present, which realizes self-motivation on an ice surface, converting the chemical potential energy of the humidity gradient from ice to kinetic energy.     

Potassium titanate whiskers on the walls of cordierite honeycomb ceramics for soot catalytic combustion

In this paper, potassium titanate whiskers was prepared via the Molten salt synthesis on the surface of cordierite ceramics for the regeneration of diesel particulate filters (DPFs). SEM, EDS, XRD, FT-IR, TG-DSC and TPO were carried out to characterize the morphology, microstructure, growth mechanism and catalytic performance of the samples. Potassium titanate whiskers with diameter (100–500 nm) and length (about 3 μm) is tightly combined with the cordierite ceramic substrate. The catalyst performance investigation demonstrates that potassium titanate whiskers decrease the soot combustion temperature apparently. The soot combustion process was studied by thermal analysis tests, and the activation energy of the combustion reaction can be calculated using Freeman-Carroll method. The carbon oxidation activation energy is 14.009 kcal/mol, and the activation energy for the catalytic reaction with potassium titanate whiskers is 6.287 kcal/mol, it can be illustrated that potassium titanate whiskers/cordierite catalyst possess excellence performance for carbon catalytic combustion. The coarseness of the interface increased because potassium titanate whiskers grew on the cordierite substrate, and the trapping ability could improve. This unique microstructure has potential application in the DPF field.     

Inorganic Electron Transport Materials in Perovskite Solar Cells

In the past decade, the perovskite solar cell (PSC) has attracted tremendous attention thanks to the substantial efforts in improving the power conversion efficiency from 3.8% to 25.5% for single-junction devices and even perovskite-silicon tandems have reached 29.15%. This is a result of improvement in composition, solvent, interface, and dimensionality engineering. Furthermore, the long-term stability of PSCs has also been significantly improved. Such rapid developments have made PSCs a competitive candidate for next-generation photovoltaics. The electron transport layer (ETL) is one of the most important functional layers in PSCs, due to its crucial role in contributing to the overall performance of devices. This review provides an up-to-date summary of the developments in inorganic electron transport materials (ETMs) for PSCs. The three most prevalent inorganic ETMs (TiO₂, SnO_2, and ZnO) are examined with a focus on the effects of synthesis and preparation methods, as well as an introduction to their application in tandem devices. The emerging trends in inorganic ETMs used for PSC research are also reviewed. Finally, strategies to optimize the performance of ETL in PSCs, effects the ETL has on J–V hysteresis phenomenon and long-term stability with an outlook on current challenges and further development are discussed.     

In-situ synthesis of zirconium oxycarbide by electroreduction of ZrO2/C in molten salt

Homogenous ZrC_xO_y powders have been successfully synthesized by in-situ electro-reduction of solid ZrO₂–C composite precursors in molten CaCl₂. The effect of applied cell voltage and molar ratio of ZrO₂ to C on preparation of ZrC_xO_y were investigated. The reduction pathway of the composite electrode was studied based on the analysis of intermediate products using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that ZrO₂ is firstly converted to CaZrO₃. The resulting CaZrO₃ is then reduced to ZrC_xO_y. The ZrC_xO_y formation is dramatically influenced by electrolysis voltage and molar ratio of ZrO₂ to C: a higher cell voltage and lower molar ratio of the ZrO₂ to C are more preferable for the formation of ZrC_xO_y powder. Homogenous ZrC_xO_y powders with particle size of ~100 nm are synthesized by ZrO₂/C starting elemental powders in CaCl₂ molten salt at 1123 K for more than 3 h, when the cell voltage is 3.0 V and the molar ratio of the ZrO₂ to carbon starting materials is 1:1.0.     

Inorganic Nanoparticles Applied as Functional Therapeutics

Inorganic nanoparticles (NPs) offer significant advantages to the biomedical field owing to their large surface area, controllable structures, diverse surface chemistry, and unique optical and physical properties. Researchers worldwide have shown that inorganic NPs and the released metal ions can act as therapeutic agents in targeted tissues or to cure various diseases without acute toxicity. In this progress report, the recent developments in inorganic NPs with different compositions directly used as therapeutics are discussed. First, the recent convergence of nanotechnology and biotechnology in biomedical applications as well as the unique functions, features, and advantages of inorganic NPs in biomedical applications are summarized. Thereafter, the biological effects of inorganic compositions in NPs which include balancing the intracellular redox environment, regulating the specific cellular signaling and cellular behaviors, and apoptosis are explained. In addition, the emerging therapeutic applications of inorganic NPs in various diseases are exemplified. Finally, the perspectives and challenges for overcoming the weaknesses of inorganic NPs as therapeutics are discussed. By carefully considering and investigating the biological effects of inorganic NPs and metal ions released from NPs, more promising inorganic NPs based therapeutic agents can be developed.     

新型无机内保温涂层的性能及应用

根据水泥烧成热耗的组成，降低高温设备表面散热是降低水泥烧成热耗的重要途径之一，而减少高温窑炉墙壁的热传导可有效降低设备的表面散热。本文在介绍无机内保温涂层隔热原理的基础上，对保温涂层的应用效果进行了对比研究，通过在传统耐火隔热材料的基础上增加新型无机内保温涂层，可有效降低高温设备外表面温度，减少水泥生产中的散热损失，达到节能降耗的目的。     

Generation-IV reactors and nuclear hydrogen production

There are dozens of hydrogen production methods and techniques from many sources such as fossil fuels, renewable energy sources and nuclear energy in the literature. Thermo-chemical methods are more efficient at higher temperatures to produce large quantities of hydrogen. In this study, a comparative overview of Generation VI nuclear reactor types for major hydrogen production methods have been researched in the literature and suggestions have been carried out.This research work is addressing that both electric power cycle and hydrogen production based on nuclear technologies need to be developed. Generation IV nuclear reactors can provide hydrogen for a worldwide hydrogen economy. Both thermo-chemical and electrolysis (hybrid) processes in hydrogen production have a promising future, especially when integrated with Generation IV nuclear power plants. Efficient heat transfer is required for both high temperature thermodynamic cycles and the high temperature steam electrolysis. Hence, highly efficient heat exchanger designs are one of the key technologies for that purpose.