聚吡咯与十二烷基苯磺酸钠修饰的钯-镍双金属电极的制备与性能表征

采用电沉积法,以钛(Ti)网为基体材料,分别用聚吡咯(PPy)修饰、PPy与十二烷基苯磺酸钠(SDBS)联合修饰,制备了钯-镍(Pd-Ni)双金属催化电极(Pd-Ni/PPy/Ti电极和Pd-Ni(SDBS)/PPy/Ti电极),探讨了SDBS掺杂对电极电化学催化活性的影响.循环伏安(CV)测试表明,在研究范围内,Pd-Ni/PPy/Ti电极的最大氢吸附峰电流值为-93 mA,Pd-Ni(SDBS)/PPy/Ti电极的最大氢吸附峰电流值为-154 mA,后者的电催化性能更优.用扫描电镜(SEM)观察了引入PPy和SDBS后电极表面形态的变化.利用电感耦合等离子体-原子发射光谱(ICP-AES)分析了电极表面Pd、Ni的负载量.X射线衍射(XRD)测试结果表明在2种电极上都形成了钯镍合金.实验表明,制备过程中引入表面活性剂SDBS,使Pd-Ni(SDBS)/PPy/Ti电极上的钯负载量减少,同时电催化性能提高,电化学脱氯潜能大.     

Sn4+对Pd/γ-Al2O3催化氯代硝基苯加氢反应影响

Pd(1.5wt%)/γ-Al2O3催化剂在催化对-氯硝基苯中硝基的选择性加氢反应时,当不往反应体系添加Sn4 离子,会有严重的脱氯反应发生;加入与Pd等物质量的Sn4 离子后,在温度70℃,氢压1.0 MPa,底物与Pd摩尔比为1 000,乙醇作溶剂的条件下,经过80 min反应,对-氯硝基苯全部转化,对-氯苯胺的选择性提高到95.5%.在上述条件下分别催化间-、邻-氯硝基苯加氢,底物全部转化时,间-、邻-氯苯胺选择性分别达95.9%、98.2%.     

不同基体材料的载钯修饰电极的制备及比较

以玻碳板、钛网和泡沫镍为基体材料,通过电沉积法制备载钯催化电极,对比研究基体材料对电极电催化活性的影响.循环伏安测试表明,Pd/GC电极、Pd/Ti电极和Pd/foam-Ni电极的氢吸附峰值分别为-23.46 mA、-59.57 mA和-60.53 mA.扫描电镜分析表明,基体材料影响钯在电极表面的沉积形态,GC板表面呈菱形块状,Ti网表面呈现针状结构,foam-Ni表面呈绒毛状.多孔foam-Ni及Ti网比表面积较大,Pd沉积后拥有更多的催化位点,增强了电极的电催化性能,增大了电极的脱氯潜能.     

Ni掺杂MoS2/石墨烯催化剂的制备及其电催化析氢活性

为了制备高效、低成本的析氢反应电催化剂,采用一步水热法制备镍掺杂二硫化钼/石墨烯复合材料(Ni_x-MoS₂/G,x=0.03,0.05,0.10),并用X-射线衍射（XRD）、扫描电镜（SEM）、高分辨透射电镜（HRTEM）和X-射线光电子能谱（XPS）对其进行表征,讨论镍掺杂对复合材料的微观结构和电催化析氢性能的影响. 结果表明,与MoS₂/G催化剂相比,镍掺杂的MoS₂/G催化剂显示了更高的电催化析氢性能,尤其当水热反应体系中的Ni和Mo的摩尔比为1∶20时,制备的Ni_0.05-MoS₂/G显示了最强的电催化析氢性能,其塔菲尔斜率为50.8 mV/dec. 电催化活性的增强主要是由于少量镍的掺杂改变了复合催化剂的形貌,使MoS₂纳米片更好地负载在石墨烯表面,暴露出更多的催化活性位点,同时镍掺杂提高了MoS₂边缘活性位的固有催化活性.     

聚吡咯/二氧化锰复合材料的合成与性能

聚吡咯制备简便、电导率可控,且比电容高、稳定性好、易于跟其他材料复合,是导电聚合物中一种颇具前景的超级电容器的电极材料.结合二氧化锰成本低、比表面积大、可逆性高、电化学性能稳定、环境友好等优点,采用一步法成功制备了聚吡咯/二氧化锰纳米复合材料.通过傅里叶红外光谱、X射线衍射、扫描电子显微镜、X射线能量色散谱等测试,对聚吡咯/二氧化锰复合材料的结构和形貌进行表征;并且通过循环伏安法和计时电位法对其进行电化学性能测试.结果表明在电流密度为1A/g时,所合成的聚吡咯/二氧化锰复合材料的电容比聚吡咯大几十倍,达到559F/g,并且保持率达到98.64%,表明聚吡咯/二氧化锰复合材料具有优良的电化学性、良好的可逆性和优秀的稳定性,与其他同类超级电容器电极材料对比具有一定的优势.     

壳聚糖修饰碳纳米管对PdNi/CNTs甲醇氧化性能的影响

以壳聚糖修饰的碳纳米管为载体,用微波辅助法制备Pd Ni/CNTs电催化剂,考察了壳聚糖的引入对Pd Ni在碳纳米管上的分散效果及对电催化性能的影响。结果表明:壳聚糖的加入改善了Pd Ni粒子的分散性,催化剂的电化学面积增大,动力学性能也得到了改进。     

污水中四氯化碳催化脱氯性能实验研究

采用化学还原法制备了纳米级Fe和纳米级Co/Fe双金属催化剂,对其催化污水中四氯化碳还原脱氯性能进行了考察,并与废铁屑催化性能进行了对比,考察了反应条件对脱氯性能的影响。实验结果表明,采用化学还原法制备的纳米级金属催化剂具有较高的比表面积和表面反应活性,纳米级Co/Fe双金属催化剂对四氯化碳的脱氯效果优于废铁屑,反应温度、脱氯时间等因素对脱氯效率有促进作用。     

双层聚吡咯/普鲁士蓝复合膜的制备与性能研究

采用层层电沉积方法制备了双层聚吡咯/普鲁士蓝复合膜修饰复合陶瓷碳电极(D-Ppy/PB/CCE),采用循环伏安法和计时安培法研究了修饰电极对过氧化氢(H2O2)的电催化性能,并优化了制备修饰电极的实验条件.结果表明,第一层Ppy膜提高了PB在电极表面的分散性;第二层Ppy膜的存在极大地提高了修饰电极的化学及电化学稳定性.该修饰电极对H2O2的还原有良好的电催化活性,安培法检测H2O2的线性范围为2.0×10-6～2.5×10-3mol/L,检出限为6.5×10-7 mol/L,灵敏度为3 593.2μA/(mmol/L)cm2.     

α-丙二醇-水相中氯代二噁英的催化加氢脱氯降解

二噁英类物质由于具有亲脂性、高毒性、化学结构稳定、难生物降解而在环境中持久存在,成为持久性有机污染物的典型代表.二嗯英的去除方法研究,一直是国际研究的热点.以5％钯/炭为催化剂,氢气作为氢源,以环境友好的α-丙二醇-水为溶剂,在1 mol/L氢氧化钠的碱性条件下,研究了1,2,7,8-四氯代二噁英（1,2,7,8-TCDD）的催化加氢脱氯降解.探讨了反应温度、初始浓度、反应时间、催化剂用量等对1,2,7,8-TCDD去除率的影响.结果表明,在反应初期（前5 min）,反应速率较快;在反应温度为45℃,催化剂用量为0.5 g/mL,反应时间为150 min的条件下,1,2,7,8-TCDD的去除率达97.0％;初始浓度对1,2,7,8-TCDD的去除率没有影响.初步试验结果表明,催化加氢脱氯降解是去除环境中氯代二嗯英的有效手段,但实际应用还有待于进一步研究.     

α\|丙二醇\|水相中氯代二噁英的催化加氢脱氯降解

二噁英类物质由于具有亲脂性、高毒性、化学结构稳定、难生物降解而在环境中持久存在,成为持久性有机污染物的典型代表.二噁英的去除方法研究,一直是国际研究的热点.以5% 钯/炭为催化剂,氢气作为氢源,以环境友好的α\|丙二醇\|水为溶剂,在1 mol/L 氢氧化钠的碱性条件下,研究了1,2,7,8\|四氯代二噁英(1,2,7,8\|TCDD)的催化加氢脱氯降解.探讨了反应温度、初始浓度、反应时间、催化剂用量等对1,2,7,8\|TCDD去除率的影响.结果表明,在反应初期(前5 min),反应速率较快;在反应温度为45 ℃,催化剂用量为0.5 g/mL,反应时间为150 min的条件下,1,2,7,8\|TCDD的去除率达97.0%;初始浓度对1,2,7,8\|TCDD的去除率没有影响.初步试验结果表明,催化加氢脱氯降解是去除环境中氯代二噁英的有效手段,但实际应用还有待于进一步研究.     

浅析英语语音教学中的/n//l/发音错误

在大学英语教学过程中,有关/n/与/l/的发音错误很常见,原因是没有完全掌握它们的发音规则。/n//l/发音规则的相似性造成了/n//l/不分的情况,而且局部方言中这两个音也不作区分,使得/n//l/混淆的情况更加严重。在教学过程中,可以通过重点讲解区分/n/与/l/的发音规则及其区别来避免/n//l/发音错误。本文同时也分析了含糊/l/音的发音错误,通过对/n/与/l/相关的发音错误分析找出大学英语语音教学行之有效的途径:在完全把握单音的发音规则的基础上,进一步强调语调的掌握,使学生拥有良好的语音。     

肼类燃料液滴的亚临界——超临界蒸发/分解燃烧理论

对肼、一甲基肼、偏二甲肼的亚临界－－超临界蒸发／分解燃烧进行了研究,计算了肼类燃料滴在不同压力下液滴温度和蒸发速度的变化历程,计算了蒸发常数、传热数和传质数,其结果和实验数据是吻合的。本文不但考虑了肼类燃料滴的亚临界蒸发／分解燃烧,还考虑到了其超临界蒸发／分解燃烧,并对达到超临界工况时的界限参数进行了计算。     

Reliability of Au/PZT/BIT/p-Si ferroelectric diode

A ferroelectric memory diode that consisted of Au/PZT/BIT/p-Si multilayer configuration was fabricated by pulsed laser deposition (PLD) technique. The reliability issues (I-V characteristics, capacitance retention, fatigue and imprint) were investigated. The I-V curve showed the conventional Schottky diode characteristics with a small current density of - 5.3×10 -10 A/cm2 at a voltage of - 4 V and 6.7×10-8 A/cm2 at a voltage of + 4V, and this characteristic can be maintained below 50℃. The capacitance variety of the ferroelectric diode was only 5 % in 10 hours after withdrawing the applied bias of + 5 V or - 5 V, indicating the diode had good capacitance retention. By applying 100 kHz bipolar pulses of 5 V amplitude, the decay in remanent polarization was only 10% after 109 switching cycles, and meanwhile the increase in coercive field was 12%. After being irradiated for 20 min with a 200 W ultraviolet ray lamp, the remanent polarization and coercive field had both varied, and a voltage shift was obse     

铬/氢/空气/氯体系的焚烧动力学分析

对含铬固体废物焚烧体系进行动力学分析是提出控制六价铬化合物排放措施的基础。本文对铬/氢/空气/氯焚烧体系进行了动力学分析,研究了温度、初始氯含量对产物中六价铬化合物含量的影响。研究表明,六价铬化合物主要以CrO2(OH)2的形式出现,最高含量出现在1700K左右;氯的存在没有导致六价铬化合物CrO2Cl2的大量生成;六价铬化合物CrO2(OH)2的含量随初始氯含量的增大略有下降。建议含铬固体废物实际焚烧过程中,避开1700K左右的温度区域,减少六价铬化合物的排放。     

St/BA/MAA/AA/VAC复合乳液的合成及其应用

采用半连续乳液种子聚合法合成苯乙烯（St）、丙烯酸丁酯（BA）、甲基丙烯酸 （MAA）、丙烯酸（AA）、醋酸乙烯酯 （VAc）的复合乳液.分析了丙烯酸对乳液电解质性能的影响,引发剂对聚合反应转化率的影响及乳化剂含量对乳液粘度的影响.通过正交试验确定组分的适当配比.该共聚乳液的粘度及固体含量符合要求,稳定性好, 性能价格比高.应用表明：用此乳液配制成地毯乳胶,胶膜具有良好的机械性能.     

减小ITO/PTCDA/P-Si/Al型光电探测器暗电流的方法

有机/无机同型异质结是一种新型的光电子元器件,由于它有制备工艺简单,一致性和稳定性好,光电转换效率高,频响特性宽等优点,在光电子领域将有广泛的应用前景.将有机半导体材料苝四甲酸二酐淀积在10 Ω·cm的P-Si无机半导体片上,形成有机/无机同型异质结,然后采用各种工艺处理方法有效的降低了它的暗电流,暗电流减小到了10-9A数量级.对降低暗电流的工艺措施和方法进行了分析和讨论.实验结果还表明,ITO/PTCDA/P-Si/Al同型异质结的暗电流主要成分是耗尽区中载流子的产生-复合电流结的反向饱和电流.     

Low temperature properties of organic-inorganic Ag/ p -CuPc/ n -GaAs/Ag photoelectric sensor

A thin organic film of p-type semiconducting copper phthalocynanine (CuPc) was deposited by vacuum evaporation on an n-type GaAs single-crystal semiconductor substrate. The fabricated Ag/p-CuPc/n-GaAs/Ag sensor was carried through an ageing process to stabilize the parameters. Voltage-current characteristics and photoelectrical response of the sensor were investigated at a wide temperature range of 82 to 350 K. Photoelectric characteristics were measured under nonmodulated filament-lamp illumination. It was observed that such sensor parameters as rectification ratio, threshold voltage, junction, shunt and series resistances, open-circuit voltage and short circuit current are temperature-dependent. It was found that wide-range voltage-current characteristics of the sensor may be described similarly to that of a Schottky barrier diode. Using the experimental data on voltage-current characteristics and absorbance of the CuPc films, the energy-band diagram of the p-CuPc/n-GaAs heterojunction was developed. It was shown that data obtained from simulation of an equivalent circuit of photoelectric sensor agreed with experimental results. Supported by the National Engineering and Scientific Commission of Pakistan     

St/BA/MAA/AA/VAC复合乳液的合成及其应用

采用半连续乳液种子聚合法合成苯乙烯(St)、丙烯酸丁酯(BA)、甲基丙烯酸(MAA)、丙烯酸(AA)、醋酸乙烯酯(VAc)的复合乳液。分析了丙烯酸对乳液电解质性能的影响,引发剂对聚合反应转化率的影响及乳化剂含量对乳液粘度的影响。通过正交试验确定组分的适当配比。该共聚乳液的粘度及固体含量符合要求,稳定性好,性能价格比高。应用表明:用此乳液配制成地毯乳胶,胶膜具有良好的机械性能。     

Modification of LiCo1/3Ni1/3Mn1/3O2 cathode material by CeO2-coating

LiCo_1/3Ni_1/3Mn_1/3O₂ was coated by a layer of 1.0 wt% CeO₂ via sol-gel method. The bared and coated LiMn_1/3Co_1/3Ni_1/3O₂ was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), cyclic voltammogram (CV) and galvanotactic charge-discharge test. The results show that the coating layer has no effect on the crystal structure, only coating on the surface; the 1.0 wt% CeO₂-coated LiCo_1/3Ni_1/3Mn_1/3O₂ exhibits better discharge capacity and cycling performance than the bared LiCo_1/3Ni_1/3Mn_1/3O₂. The discharge capacity of 1.0 wt% CeO₂-coated cathode is 182.5 mAh·g⁻¹ at a current density of 20 mA·g⁻¹, in contrast to 165.8 mAh·g⁻¹of the bared sample. The discharge capacity retention of 1.0 wt% CeO₂-coated sample after 12 cycles reaches 93.2%, in comparison with 86.6% of the bared sample. CV results show that the CeO₂ coating could suppress phase transitions and prevent the surface of cathode material from direct contact with the electrolyte, thus enhance the electrochemical performance of the coated material.     

Memory characteristics of Au/PZT/BIT/p-Si ferroelectric diode

A ferroelectric memory diode consisting of Au/PZT/BIT/p-Si multilayer configuration has been fabricated by pulsed laser deposition (PLD) technique. The ferroelectric properties and the memory characteristics are investigated. The P-E curve of the PZT/BIT/p-Si films system had an asymmetry saturated hysteresis loop with P, = 15 μC/cm2 and Ec = 48 kV/cm, and the decay in remanent polarization was only 10% after 109 switching cycles, meanwhile the increase in coercive field was 12% . The C-V hysteresis loop and the I-V curve showed a memory effect derived from the ferroelectric polarization of PZT/BIT films, and the current density was 6.7 × 10-8 A/cm2 at a voltage of + 4V. Our diode had nonvolatile and nondestructive memory readout operation. There was a read current disparity of 0.05 μA for logic "1" and logic "0" at a read voltage of + 2V, and the stored logical value ("1" or "0") could be read out in 30 min.