金矿封闭溶样法的优化

封闭溶矿体系由HNO3-NH4HF2-KMnO4-NaCl调整为HCl-NaClO3-NH4HF2,消除了传统封闭溶样法去除碳(包括石墨)、硫、碳酸盐等过程中可能出现的样品迸溅外溢、溶矿困难而导致分析测定结果偏低的不利因素,除硫速度和体系的反应体积易于控制,新生态[Cl]的产生速度和浓度大大增加,增加了反应容器内的压强值,进一步提高了矿石溶解效率,降低了对环境的污染程度。     

金属铜在铜（Ⅱ）氨溶液中的溶解行为

对铜在Cu（Ⅱ）-NH3-（NH4）：SO4-H2O体系中的溶解行为进行了研究,分析了影响铜溶解速率的因素。实验结果表明,溶液中初始铜离子浓度、氨和硫酸铵浓度、温度以及空气通入量均对铜的溶解速率有较大的影响。得到了较适宜的溶铜条件：温度50℃,初始铜离子和氨的浓度分别为1．0mol／L和7．5mol／L,硫酸铵浓度为0．5mol／L,同时通入适量的空气。     

软水生产系统扩容改造及技术优化

针对莱钢原软化水系统生产操作手动落后、溶盐体力劳动大、无前置过滤器、无化学在线连续监测仪表等缺陷,进行技术优化改进,实现了一键式溶盐、交换器的运行自动化控制等技术优化。     

Exploring the reactivity and nanoscale morphology of de-alloyed layers

De-alloying of a 70Cu-30Pt alloy has been studied with a view to testing the thermodynamic prediction that a novel kind of underpotential or sub-potential electrodeposition may be possible in such highly curved nanoporous solids. After de-alloying in H₂SO₄ solution containing CuSO₄, successive cathodic processes of PtO monolayer reduction, UPD of Cu, and a Cu plating process were identified, all occurring at potentials above the Cu equilibrium potential. The maximum amount of charge in the third plating process was determined to be about three monolayers, averaged over the whole porous surface. This seems to rule out the possibility that this process is some kind of second UPD layer or other non-bulk form of Cu plating. A probable explanation is that small amounts of bulk Cu are plating into regions of high negative curvature within the de-alloyed material. However X-ray diffraction did not show any evidence of bulk Cu.     

Investigation of a Novel Catalyst Coated Membrane Method to Prepare Low‐Platinum‐Loading Membrane Electrode Assemblies for PEMFCs

In this work, a novel catalyst coated membrane (CCM) approach–a catalyst‐sprayed membrane under irradiation (CSMUI)–was developed to prepare MEAs for proton exchange membrane fuel cell (PEMFC) application. Catalyst ink was sprayed directly onto the membrane and an infrared light was used simultaneously to evaporate the solvents. The resultant MEAs prepared by this method yielded very high performance. Based on this approach, the preparation of low‐platinum‐content MEAs was investigated. It was found that for the anode, even if the platinum loading was decreased from 0.2 to 0.03 mg cm^–2, only a very small performance decrease was observed; for the cathode, when the platinum loading was decreased from 0.3 to 0.15 mg cm^–2, just a 5% decrease was detected at 0.7 V, but a 35% decrease was observed when the loading was decreased from 0.15 to 0.06 mg cm^–2. These results indicate that this approach is much better than the catalyst coated gas diffusion layer (GDL) method, especially for the preparation of low‐platinum‐content MEAs. SEM and EIS measurements indicated ample interfacial contact between the catalyst layer and the membrane.     

Platinum Nanoparticles Anchored on TiO2/C Nanowires as a High Performance Catalyst for Hydrogen Peroxide Eletroreduction

In this paper, we employed the as‐prepared TiO₂/C core/shell nanoarrays (TiO₂/C) obtained by a facile thermal evaporation method as a three‐dimensional (3D) architecture to support Pt nanoparticles through an optimized electrodeposition process. The morphology and structure of the as‐prepared electrode are characterized by X‐ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Its catalytic performance towards H₂O₂ electroreduction in basic medium is evaluated by linear sweep voltammetry (LSV) and chronoamperometry (CV). Results revealed that the electrode exhibits significantly high catalytic activity. The current density reached –0.172 A cm⁻² in 1 mol dm⁻³ NaOH and 0.5 mol dm⁻³ H₂O₂ at –1.1 V (vs. Ag/AgCl). This high performance might be due to the 3D electrode architecture inheriting the high electronic conductivity from carbon shell and providing a short pathway for the ion diffusion, and the using of Pt owning an excellent catalytic activity.     

Passive and transpassive behaviour of CoCrMo in simulated biological solutions

In this work, the behaviour of a CoCrMo alloy under simulated body conditions was investigated. More specifically, the electrochemical properties of the alloy and the relevant mechanisms in the passive and transpassive states were studied in detail. Electrochemical techniques such as potentiodynamic and potentiostatic polarisation, cyclic voltammetry, rotating disc electrode and electrochemical impedance spectroscopy were employed. Further, ex situ X-ray photoelectron spectroscopy analysis of the passive films was carried out. A good correlation between the results obtained from all the experimental techniques was achieved. Overall, it was found that the passive film on CoCrMo changed in composition and thickness with both potential and time. The passive behaviour of the CrCrMo alloy is due to a formation an oxide film highly enriched with Cr (≈90% Cr oxides) on the alloy surface. The passive and transpassive behaviour of the alloy is hence dominated by the alloying element Cr. In the transpassive region, strong thickening of the oxide film takes place, combined with a change in the composition of the film, and strongly increased dissolution rate. In the transpassive region, all alloying elements dissolve according to the composition of the alloy. The metal ion release is also very strongly enhanced by cyclic variation of the potential between reducing and oxidizing conditions. In this case, during activation/repassivation cycles, cobalt dissolution is greater than expected from the composition of the alloy. Therefore, active dissolution behaviour is mainly dominated by the alloying element Co.     

Electroreduction of dioxygen (ORR) in alkaline medium on Ag/C and Pt/C nanostructured catalysts—effect of the presence of methanol

Ag/C catalysts with different loading were prepared using a colloidal route to obtain well dispersed catalysts on carbon, with a particle size close to 15 nm. An amount of 20 wt.% Ag on carbon was found to be the best loading in terms of current density and mass activity. The 20 wt.% Ag/C catalyst was then studied and the kinetics towards ORR was determined and compared with that of a 20 wt.% Pt/C catalyst. The number of exchanged electrons for the ORR was found to be close to four with the rotating disk electrode (RDE) as well as with the rotating ring disc electrode (RRDE) techniques. From the RDE results, the Tafel slopes b, the diffusion limiting current density inside the catalytic film (j_l^film) and the exchange current density (j₀) were evaluated. The Tafel slopes b and diffusion limiting current densities inside the catalytic film (j_l^film) were found to be in the same order for both catalysts, whereas the exchange current density (j₀), which is a suitable estimation of the activity of the catalyst, was at least 10 times higher at the Pt/C catalyst than at the Ag/C catalyst. The behavior of both catalysts in methanol containing electrolyte was investigated and it was found that at a low methanol concentration, the Pt/C catalyst was quasi-tolerant to methanol. But, at a high methanol concentration, the ORR at a Pt/C was affected. However, the Pt/C catalyst showed in each case better activity towards ORR than the Ag/C catalyst, even if the latter one was less affected by the presence of methanol than the former one.     

影响陶瓷餐具中温釉铅溶出量几个因素的探析

对陶瓷餐具中温釉在配方、熔块制各、氧化物、着色剂添加量、烧成方式和烧成温度几方面的试验，分析和探讨了以上因素对陶瓷餐具中温釉铅溶出量的影响，提出了在陶瓷中温釉生产中应该注意及改进的几个方法。     

沸石的碱处理溶解

晶体的溶解与晶体的生长存在着密切的联系，详细研究沸石晶体的溶解行为将有助于更好的理解沸石晶体的生长机理。鉴于目前对沸石晶体的碱处理溶解行为的研究尚处于初始阶段，所以从沸石碱溶解的几点关键内容出发，如沸石的硅铝比对沸石碱处理的影响，焙烧“活化”后沸石的碱处理溶解行为的变化，沸石与其无定形前驱物的溶解性差异以及沸石的溶解机理和溶解动力学方程方面，综述了有关沸石碱处理溶解研究方面的最新动态。