硫化亚铁阴极的电极过程机理

应用循环伏安法研究了硫化亚铁阴极的电极过程机理 ,电极反应过程伴随着难溶硫化亚铁的形成与溶解 ,该电极过程受欧姆电阻控制 .根据循环伏安曲线峰电流和峰电位与扫描速度平方根成线性关系 ,提出了电极过程的欧姆电阻控制模型 ,导出峰电位和峰电流与扫描速度之间的关系式 ,理论分析与实验结果一致 .     

等离子喷涂纳米FeS涂层的摩擦磨损性能研究

利用等离子喷涂技术在GCr15钢表面制备出纳米FeS固体润滑涂层,采用MHK-500型摩擦磨损试验机评价了FeS涂层在油润滑和干摩擦2种条件下的摩擦磨损性能,用扫描电子显微镜和X射线衍射仪观察分析了涂层的形貌、结构、物相组成和磨损表面形貌.结果表明,纳米FeS涂层的物相主要为六方FeS,还有少量Fe1-xS和氧化物,涂层由尺寸在50～100 nm的颗粒组成.与GCr15钢相比,纳米FeS涂层的减摩耐磨性明显提高,尤其在油润滑条件下摩擦系数降低1倍,在高载荷(375 N)条件下磨痕宽度降低近1倍.在油润滑和干摩擦条件下,FeS涂层的主要磨损失效形式均为塑性变形.     

PVP辅助溶剂热技术制备FeS_2纳米粉体

FeS2(pyrite)具有合适的带隙宽度(0.95 eV)、高的光吸收系数(可见区α=6×105cm-1)及优异的光学、电学及磁学性质,且其元素储量丰富、价格低廉、无毒,目前已成为薄膜太阳能电池的最佳吸收材料之一[1,2].但硫化铁是一个非常复杂的体系,存在许多不同配比的物相组成,如FeS、Fe1-xS、Fe7S8、Fe9S10、Fe3S4、FeS2(pyrite)及FeS2(marcasite)等[3].     

Sulphur capturing by an inertinite rich high ash bituminous coal during conversion in a pilot packed bed reactor

Sulphur is liberated from the coal structure and released in various forms during coal thermal processing. The possibility of sulphur capture, through injection of SO₂ into a packed coal bed in a pilot packed bed reactor operated under controlled conditions, was investigated. Results showed that SO₂ injection into a packed coal bed leads to sulphur capturing mainly in the coal mineral matter. Mineralogical analysis (XRD) of the ash samples obtained from the experiments indicates that the sulphur-capture products that are formed include FeS, CaS and small amounts of organically associated sulphur. Troilite (FeS) was observed in the SO₂ treated samples, while no troilite was observed in the reference samples. Calcite and dolomite are transformed into CaO and other calcium-containing compounds in the pyrolyses zone, with some CaS being formed in the gasification zone via the reaction between SO₂ and CaO in the presence of CO from the gasification reactions. CaO formed at the high temperatures in the combustion and ash zone is transformed into CaSO₄ upon reaction with SO₂ as an oxidizing atmosphere prevails in this zone. The existence of these compounds is dependent on the extent of oxidising or reducing conditions during the process, with CaS favoured under reducing conditions and CaSO₄ favoured under oxidising conditions.     

甲醇在FeS2(100)完整表面的吸附和分解

采用基于第一性原理的密度泛函理论结合周期平板模型方法, 研究了甲醇分子在FeS₂(100)完整表面的吸附与解离. 通过比较不同吸附位置的吸附能和构型参数发现: 表面Fe位为有利吸附位, 甲醇分子通过氧原子吸附在表面Fe位, 吸附后甲醇分子中的C―O键和O―H键都有伸长, 振动频率发生红移; 甲醇分子易于解离成甲氧基CH3O和H, 表面Fe位仍然是二者有利吸附位. 通过计算得出甲醇在FeS₂(100)表面解离吸附的可能机理: 甲醇分子首先发生O―H键的断裂, 生成甲氧基中间体, 继而甲氧基C―H键断裂, 得到最后产物HCHO和H₂.     

Biogenic Iron Sulfide Nanoparticles to Enable Extracellular Electron Uptake in Sulfate‐Reducing Bacteria

Microbes synthesize cell‐associated nanoparticles (NPs) and utilize their physicochemical properties to produce energy under unfavorable metabolic conditions. Iron sulfide (FeS) NPs are ubiquitous and are predominantly biosynthesized by sulfate‐reducing bacteria (SRB). However, the biological role of FeS NPs in SRB remains understudied. Now, conductive FeS NPs function is demonstrated as an electron conduit enabling Desulfovibrio vulgaris Hildenborough, an SRB strain, to utilize solid‐state electron donors via direct electron uptake. After forming FeS NPs on the cell surface, D. vulgaris initiated current generation coupled with sulfate reduction on electrodes poised at ?0.4 V versus standard hydrogen electrode. Single‐cell activity analysis showed that the electron uptake and metabolic rate via FeS NPs in D. vulgaris were about sevenfold higher than those via native cell‐surface proteins in other SRB.     

Novel electrosynthesis of CdS/FeS nanocomposite-modified poly(o-phenylenediamine) with views to their use as a biosensor for Escherichia coli

This article proposes a new electrochemical sensor for Escherichia coli (E. Coli) composed of poly(o-phenylenediamine) (PoPD) and CdS/FeS nanocomposites (PoPD|CdS/FeS). The preparation of the modified electrodes used for this purpose and their subsequent use as a sensor comprise a simple, fast and reproducible technique. The characterization of the CdS/FeS nanocomposites and their subsequent inclusion on PoPD was performed by X-ray diffraction (XRD), Raman, field emission scanning electron microscopy (FESEM), high-resolution transmission electron microscopy (HR-TEM) and computational methods; For the nanocomposites an average size of 100 nm was obtained after applying a reduction potential for 5 s over the polymeric matrix. The electrochemical characterizations confirmed that the inclusion of the nanocomposites improved the amperometric response, allowing the developed material to be used as an electrochemical sensor for E. Coli. The figures obtained gave the linear equation j = -6.89 × 10⁻¹⁴ × CFU + 5.64 × 10⁻⁵, with an R² of 0.995, for 10 replicates. Furthermore, the limit of detection (LOD) was 6.1 × 10⁵ CFU/mL, and the limit of quantification (LOQ) was 6.1 × 10⁶ CFU/mL.     

Mild corrosion behavior on sulphurized steel surface during friction

After treatment by low temperature ion sulphuration, the solid lubrication sulphuration layers (FeS films) were produced on the AISI 1045 and stainless steel. A mass of corrosion peeling pits occurred on the worn scars of 1045 steel sulphuration layer after wear test, whereas none of them on the stainless steel one. AFM was used to observe the morphology of sulphuration layer, SEM equipped EDS was utilized to analyze the morphologies and compositions of worn scars. XPS and XRD were employed to detect the valence states of sulphuration layer and its worn scars, as well as the phase structures. The results showed that during friction, under the frictional heat, the sulfate radical with mild corrosion was produced, so that the 1045 steel without any anti-corrosion was corroded in some certain, meanwhile the stainless steel was not corroded depending on its excellent corrosion resistance.