Metal hydride air conditioner

1 IntroductionMetal hydrides can be used as the working materials in the field of energy technology and show very Fig .1 The working principle of a single-stage heatpumppromising potentials to contribute tothe rational use of en-ergy . One i mportant application of hydrogen energy is themetal hydride heat pump[1 -6], which uses the hydrogen re-action enthalpy to generate useful cold or heat , and themetal hydride air conditioner is one i mportant form of it .The correlative reaction processes…     

Study on hydrogen evolution performance of the carbon supported PtRu alloy film electrodes

The carbon supported PtRu alloy film electrodes having Pt about 0.10 mg/cm2 or even less were prepared by ion beam sputtering method (IBSM). It was valued on the hydrogen analyse performance, the temperature influence factor and the stability by electroanalysis hydrogen analyse method. It was found that the carbon supported PtRu alloy film electrodes had higher hydrogen evolution performance and stability, such as the hydrogen evolution exchange current density (j0) was increase as the temperature (T) rised, and it overrun 150 mA/cm2 as the trough voltage in about 0.68V, and it only had about 2.8, decline in 500 h electrolytic process. The results demonstrated that the carbon supported PtRu alloy film electrodes kept highly catalytic activity and stability, and it were successfully used in pilot plant for producing H2 on electrolysis of H2S.     

Palladium-rare-earth metal alloys-advanced materials for hydrogen power engineering

Hydrogen of no less than 99. 999 % (vol. fraction) purity is a principal power media of hydrogen power engineering. A single method for the preparation of high purity hydrogen consists in its separation from vapour-gas mixtures via the selective diffusion of hydrogen through a palladium membrane. The rate of hydrogen diffusion and the strength and stability during the operation in aggressive gases are important characteristics of palladium membranes. The increase in the strength, plasticity, and hydrogen-permeability of membrane alloys can be reached by alloying palladium with the formation of solid solutions.The formation of wide ranges of palladium-rare-earth metal (REM) solid solutions is an interesting feature of palladium. Earlier, we have shown that the alloying of Pd with REM substantially increases the rate of hydrogen diffusion and markedly increases the strength of palladium on retention of the adequate plasticity.In this work, we have studied alloys of the Pd-Y and Pd-Y-Me systems. It was shown that the following conditions should be satisfied to prepare high-quality alloys exhibiting high service properties: (1)the use of high-purity components (whose purity is no less than 99.95%, mass fraction), in particular,high-purity Y prepared by vacuum distillation, and (2) holding the reached purity for the final product.For this purpose, we suggested a cycle of manufacturing operations including the preparation of a vacuumtight foil of 50 (m thick as the final stage.The hydrogen-permeability of the alloys was measured at different temperatures and hydrogen pressures. The instability of operation of binary Pd-Y alloys w alloying the composition with a Ⅷ Group metal. For example, the alloy of the optimum composition Pd-8Y-Me in the annealed state exhibits the following mechanical properties: HV= 75 kg/mm2 , σu = 58 kg/mm2 , and δ= 20%. Its hydrogen-permeability (QH2) measured as a function of the temperature exceeds that of the Pd-23Ag alloy (that is widely used by foreign companies) by a factor of 1.5-2; it is 3.6-4.7 m3/m2 hMPa0.5 at 300-600℃, respectively.The alloys exhibiting the high hydrogen-permeability combined with the high mechanical properties shows promise as materials for diffusion hydrogen purification devices whose productivity reaches tens thousands nm3/h.     

Palladium-rare-earth metal alloys-advanced materials for hydrogen power engineering

Hydrogen of no less than 99. 999 , (vol. fraction) purity is a principal power media of hydrogen power engineering. A single method for the preparation of high purity hydrogen consists in its separation from vapour-gas mixtures via the selective diffusion of hydrogen through a palladium membrane. The rate of hydrogen diffusion and the strength and stability during the operation in aggressive gases are important characteristics of palladium membranes. The increase in the strength, plasticity, and hydrogen-permeability of membrane alloys can be reached by alloying palladium with the formation of solid solutions.The formation of wide ranges of palladium-rare-earth metal (REM) solid solutions is an interesting feature of palladium. Earlier, we have shown that the alloying of Pd with REM substantially increases the rate of hydrogen diffusion and markedly increases the strength of palladium on retention of the adequate plasticity.In this work, we have studied alloys of the Pd-Y and Pd-Y-Me systems. It was shown that the following conditions should be satisfied to prepare high-quality alloys exhibiting high service properties: (1)the use of high-purity components (whose purity is no less than 99.95,, mass fraction), in particular,high-purity Y prepared by vacuum distillation, and (2) holding the reached purity for the final product.For this purpose, we suggested a cycle of manufacturing operations including the preparation of a vacuumtight foil of 50 (m thick as the final stage.The hydrogen-permeability of the alloys was measured at different temperatures and hydrogen pressures. The instability of operation of binary Pd-Y alloys w alloying the composition with a Ⅷ Group metal. For example, the alloy of the optimum composition Pd-8Y-Me in the annealed state exhibits the following mechanical properties: HV= 75 kg/mm2 , σu = 58 kg/mm2 , and δ= 20,. Its hydrogen-permeability (QH2) measured as a function of the temperature exceeds that of the Pd-23Ag alloy (that is widely used by foreign companies) by a factor of 1.5-2; it is 3.6-4.7 m3/m2 hMPa0.5 at 300-600℃, respectively.The alloys exhibiting the high hydrogen-permeability combined with the high mechanical properties shows promise as materials for diffusion hydrogen purification devices whose productivity reaches tens thousands nm3/h.     

Study on catalyst for the sodium borohydride hydrolysis

1IntroductionAs ani mportant part in the newenergy sources,hydrogen energy technologies include the H2genera-tion,storage and application.The hydrogen storageis the key step[1].People pay more and more attentionto the chemical hydrogen storage technology due toits high hydrogen storage rate,safe and stable applica-tion.Sodiumborohydride(NaBH4)is a complex hydride.When sodiumborohydrideis used to store hydro-gen,andits hydrogen storage capacityis theoretically about10.8%(mass fraction)[2].Na…     

Study of improved electrochemical performance of LiFePO_4/C electrode for LIB

1IntroductionThe ever-growing demand for portable batteries with high energy density is exerting pressure for thedevelopment of advanced Li-ion batteries.The remaining challenges are cost,abuse tolerance,and low-temperature performance.One critical challenge is the thermal stability of the battery components.Pres-ently LiFePO4with a structure of olivine-type,first published by Goodenough[1],has become more con-cerned because of its high energy density,low raw materials cost,environmental fr…     

Study on the random simulation times of mining engineering reliability

Introduction In general, the analysis and simulation methods are adopted by the calculation of the project reliability. These methods mainly include Monte-Carlo simula-tion method[1], interfered area method, first-order sec-ondmoment method[2], respond surface method[3], the direct sampling method, importance sampling method[4]. Among them, the Monte-Carlo simulation method is the common way to predict and estimate the failure probability. The main thought of this method is: the probability …     

Multilayered structures InSb_(1-x)Bi_x/InSb-materials for infrared photodetectors

In the workinvestigations of electron energy spectrumdependence fromthickness(l)and number(N)of layers are carried out as well as treating with rays process in5-11layer heterostructures InSb0.97Bi0.03/InSbis considered bykp-and matrix methods.Calculations verified by experi ments[1]showthat with anaddition of every pair of layers(well/barrier)there is an energy level appearance.N-increasing leads tospectrumdisplacement into the NIR-field.For thick(l>0.1mcm)layers it's typical high NIR-sen…     

Study on sintering technique of NiFe2O4/SiCp used as matrix of inert anodes in aluminium electrolysis

In order to improve deficiencies of NiFe2O4 spinel used as matrix of inert anode in aluminium electrolysis, NiFe2O4/SiCp were prepared by the solid state reaction for the first time. Microstructural changes were observed by scanning electronic microscope and phase was determined with X-ray detector. Effect of sintering temperature and times on density, porosity and microstructure were researched, and the reasons that caused the difference were discussed deeply. At the same time the thermodynamical compatibility of NiFe2O4 and SiC was proved under 1200℃ by DTA.The results showed that the microstructure was more homogeneous when the sintering temperature reached 1 180℃and the density attained their maximum about 6 h sintering. The appropriate sintering technique of NiFe2 O4/SiCw composite materials was 1180℃× 6 h.     

Metal hydride air conditioner

The relationship among the hydrogen storage properties, cycling characteristics and thermal parameters of the metal hydride air conditioning systems was investigated. Based on a new alloy selection model, three pairs of hydrogen storage alloys, LaNi4.4 Mn0.26 Al0.34 / La0.6 Nd0.4 Ni4.8 Mn0.2 Cu0. 1, LaNi4.61Mn0. 26 Al0.13/La0.6 Nd0.4 Ni4.8 Mn0.2 Cu0. 1 and LaNi4.61 Mn0.26 Al0.13/La0.6 Y0.4 Ni4.8 Mn0. 2, were selected as the working materials for the metal hydride air conditioning system. Studies on the factors affecting the COP of the system showed that higher COP and available hydrogen content need the proper operating temperature and cycling time,large hydrogen storage capacity, flat plateau and small hysterisis of hydrogen alloys, proper original input hydrogen content and mass ratio of the pair of alloys. It also needs small conditioning system was established by using LaNi4.61 Mn0.26 Al0. 13/La0.6 Y0.4 Ni4.8 Mn0.2 alloys as the working materials, which showed that under the operating temperature of 180℃/40℃, a low temperature of 13℃ was reached, with COP =0.38 and Wnet =0.09 kW/kg.     

Study on hydrogen evolution performance of the carbon supported PtRu alloy film electrodes

The carbon supported PtRu alloy film electrodes having Pt about 0.10 mg/cm2 or even less were prepared by ion beam sputtering method (IBSM). It was valued on the hydrogen analyse performance, the temperature influence factor and the stability by electroanalysis hydrogen analyse method. It was found that the carbon supported PtRu alloy film electrodes had higher hydrogen evolution performance and stability, such as the hydrogen evolution exchange current density (j0) was increase as the temperature (T) rised, and it overrun 150 mA/cm2 as the trough voltage in about 0.68V, and it only had about 2.8% decline in 500 h electrolytic process. The results demonstrated that the carbon supported PtRu alloy film electrodes kept highly catalytic activity and stability, and it were successfully used in pilot plant for producing H2 on electrolysis of H2S.     

La2Mg17稀土镁基储氢合金制备工艺及储氢性能研究

采用熔剂覆盖熔炼的方法制备了La2Mg16Ni合金,并研究了该合金的吸放氢性能及吸放氢过程中合金的相结构变化.用Ni取代La2Mg17合金中的部分Mg,可提高储氢合金的吸放氢动力学性能,在温度高于553K时,所制备的储氢合金具有良好的吸放氢平台性能,其储氢容量可达到4.16％.     

酞菁铁对新型La-Mg-Ni基储氢合金电化学性能的影响Effect of Phthalocyanine Iron on Electrochemical Properties of the New La-Mg-Ni-based Hydrogen Storage Alloy 王新颖 黄红霞* 谢文强

为提高La-Mg-Ni基储氢合金La0.73Ce0.18Mg0.09Ni3.20Al0.21Mn0.10Co0.60在Ni/MH二次电池中的电化学性能,将合成的酞菁铁作为添加剂添到合金中,考察不同含量的酞菁铁对La-Mg-Ni基储氢合金电化学性能的影响。通过分析紫外和红外图谱,可知合成出目标产物酞菁铁。添加酞菁铁后,合金的相结构没有变化。将不同含量的酞菁铁加入到储氢合金后,合金的最大放电容量变化不大,循环50次后的放电容量保持率从62.6%提高到75.3%。合金电极的交换电流密度I0、极限电流密度IL均有较大幅度增加,抗腐蚀性能也有提高。表明酞菁铁有效改善了储氢合金电极的综合电化学性能。     

氢气还原合成LiFePO_4的动力学探讨

以H3PO4、Fe2O3和LiOH.H2O为原料,用H2还原合成了橄榄石型LiFePO4材料。采用Rietveld全谱拟合法检测不同温度和时间下LiFePO4的转化率,通过研究其转化率与时间、温度的关系,确定了H2还原合成LiFePO4的反应机理、反应级数和速率常数,并给出了控制步骤的转化温度和各阶段的活化能。根据动力学研究的结果,采用"H2气氛低温合成,N2气氛高温生长"机制合成了LiFePO4/C复合材料。该材料具有单一的橄榄石结构,颗粒尺寸细小均匀,0.1C倍率下,首次放电容量达152.5 mAh/g,放电效率为95.4%,循环30次后,电池的容量保持率达98.4%。     

纳米锗颗粒膜的结构与拉曼散射

用直流磁控溅射方法制备的纳米Ge颗粒膜．通过XRD表征和LRS谱分析，发现沉积态颗粒膜主要为无定形态的Ge团簇，同时在溅射沉积过程中有少量Ge被氧化成非晶态的GeO．颗粒膜经过真空退火处理，形成纳米级的Ge晶和GeO晶体．退火态的膜层结构比沉积态的疏松．对于薄膜纳米颗粒的结构，提出Core—Shell结构模型。解释了Raman散射谱中新出现的150cm^-1和215cm^-1的Raman散射峰．     

6060铝合金阳极氧化膜受热开裂行为影响因素的分析

研究了硫酸浓度、电流密度、氧化温度、氧化后存放时间、封孔时间以及加热温度和加热时间等因素,对6060铝合金阳极氧化膜受热开裂行为的影响.结果表明:在H2SO4浓度为200 g/L左右,氧化温度为19℃左右,电流密度为1.3～1.6 A/dm2的阳极氧化工艺参数下,所得到的氧化膜热裂性能较好,氧化膜的抗热裂点温度为62℃...     

CuS/La2Ti2O7光催化剂的制备及光催化产氢性能研究

通过水热—溶剂热法合成了CuS/La₂Ti₂O₇复合光催化剂，以乳酸为牺牲剂，在模拟太阳光下考察了制备样品的光催化分解水产氢性能，并采用X射线粉末衍射、扫描电镜、透射电镜、低温氮吸—脱附、紫外—可见漫反射、电化学表征等手段对样品的理化性能进行了详细表征，探究了影响其光催化性能的关键因素。结果表明复合CuS后La₂Ti₂O₇样品在模拟太阳光下能催化分解水产氢，当CuS复合量质量分数为0.5%时，复合样品光催化产氢的活性最佳，产氢速率为12.57 μmol/h，并具有良好的活性稳定性；La₂Ti₂O₇复合CuS后，样品的光响应性能增强，瞬态光电流增强，阻抗降低，有利于光生电荷的有效分离，从而提高了复合样品的光催化活性。     

MOFs衍生的CoZnSe@NC电催化剂的制备及析氧性能研究

硒化锌因具有与铂类似的电子结构及低成本而受到广泛关注,但目前硒化锌主要应用于电催化析氢反应(HER)中,其析氧反应(OER)活性仍有待提高,并且传统方法合成的硒化锌粒子尺寸较大且分散性较差.基于此,以双金属CoZn-ZIF为前驱体(Co作为OER活性成分,可有效提高材料的OER性能),通过一步高温硒化得到双金属CoZnSe和氮掺杂碳复合材料(记为CoZnSe@NC).利用X射线粉末衍射(XRD)和扫描电子显微镜(SEM)对复合材料的结构和形貌进行表征,并对其电催化析氧性能进行了测试.结果表明:双金属CoZnSe@NC较单金属ZnSe@NC具有更好的OER性能(10和50 mA/cm²电流密度下CoZnSe@NC的过电位分别为268和354 mV);此外,CoZnSe@NC经长时间多电流步骤(Multi-Current Steps)测试后性能基本保持不变,展现了较好的电化学稳定性.     

黄铜矿、黄铁矿、金与浮选剂作用电化学研究

以伏安法和循环伏安法研究了黄铜矿、黄铁矿和金的电极在调整剂CaO、CaOCl_2、Na_2CO_3、Na_2S或捕收剂丁基黄药、丁基铵黑药和十二烷基硫醇或两者同时存在的溶液中所表现出来的电化学行为。研究结果表明:调整剂的使用会影响金电极的表面性质,但在捕收剂同时存在时,这些影响有不同程度的减弱。在CaO或CaOCl_2作用下,黄铜矿和黄铁矿表面氧化速度加快,并生成新的表面产物。XPS的进一步研究表明:这些表面产物都为含钙化合物,但黄铜矿麦面生成的含钙化合物组成与黄铁矿表面生成的含钙化合物组成不同,这是利用CaO或CaOCl_2进行黄铜矿与黄铁矿浮选分离的根本依据。