Pt/MoO3/ZrO2催化剂的制备及三效催化性能的研究

采用浸渍法制备了MoOz/ZrO2,用低温氮吸附-脱附法和NH3-程序升温脱附法(TPD)分别对其比表面积和酸碱性进行了表征.结果表明,MoO3/ZrO2具有106.8m2/g的比表面积和超强酸的性能.用等体积浸渍法制备了Pt/MoO3/ZrO2催化剂,在汽车尾气模拟气中考察了其对C3H8、CO和NO的催化活性.与传统三效催化剂Pt/La2O3/Al2O3相比较,Pt/MoO3/ZrO2具有更好的低温起燃性能和更宽的空燃比窗口,并显著地改善了C3H8在富氧状态下的转化效率.通过XRD、H2-TPR对催化剂进行了表征,结果表明,Pt在催化剂载体上具有高度的分散性和优异的氧化还原性能.     

乙二醇稳定的NaBH4还原法制备纳米Pt/C催化剂

分别采用乙二醇(EG)和H2O为溶剂,通过NaBH4还原法在酸性pH≤2和碱性pH≥12条件下制备了铂担裁量为20%(质量分数)的Pt/C催化剂,利用TEM、CV及LSV等方法对催化剂进行了表征与测试,考察了EG在NaBH4还原法中对铂纳米颗粒的稳定作用.结果表明,EG作溶剂、碱性pH≥12时,通过NaBH4还原法制备得到了平均粒径约2.5nm、粒径分布窄、在碳裁体上分散均匀的Pt/C催化荆;该催化剂的电化学比表面为74.4m2/g Pt,0.8V vs NHE时通过LSV得到的单位质量铂对甲醇电催化氧化的电流密度为229.1mA/mg Pt,分别是相同条件下H2O作溶剂时制备得到的Pt/C催化剂的5.倍和5.3倍.     

PtIr/C合金催化剂的制备及其电催化性能

以碳黑(Vulcan XC 72)为载体,氯铱酸(H2IrCl6.6H2O)和氯铂酸(H2PtCl6.6H2O)为前驱体,聚乙烯基吡咯烷酮(PVP,polyvinylpyrrolidone)为保护剂,首次采用高压氢还原方法制备出PtIr/C合金催化剂,并对其进行不同温度的通H2热处理。运用XRD、TEM和XPS对PtIr/C合金催化剂进行表征。结果表明,Pt与Ir发生合金化,PtIr合金纳米粒子均匀分散在碳黑表面。经400和700℃热处理后,PtIr合金纳米粒子的平均粒径仅从4.46nm长大至4.56和5.58nm,且随着热处理温度的升高,其晶型不断完善。用CO-stripping伏安法,循环伏安法(CV)、计时电流法(CA)等电化学测试方法测试PtIr/C合金催化剂的电催化性能,发现400℃热处理的PtIr/C合金催化剂,在酸性溶液中对CO氧化的起始电位明显提前,对甲醇氧化具有最高的催化活性。     

Pt/C催化剂制备及CO催化氧化性能研究

采用大气压介质阻挡放电辅助氢气热还原方法和氢气热还原方法制备Pt/C催化剂,考察了制备方法及Pt负载量对Pt/C催化性能的影响。采用X-射线衍射(XRD)、循环伏安法、CO催化氧化反应研究Pt/C催化剂的晶相结构、电催化性能和CO催化氧化活性。结果表明:大气压介质阻挡放电辅助氢气热还原所制备的样品具有更高的电化学活性和CO催化氧化活性。当Pt负载量在2%到10%之间变化时,Pt/C-PC催化活性随负载量增加而增加。XRD测试结果显示当Pt负载量为2%,5%和10%时,Pt粒径分别为:10.6 nm,9.1 nm和6.4 nm,说明采用等离子体辅助氢气热还原方法制备的Pt/C-PC催化剂,Pt负载量越大,Pt粒径越小,CO催化氧化活性更高。     

一步法热分解制备染料敏化太阳能电池Pt对电极

用旋涂热分解前驱H2PtCl6·6H2O溶液制备Pt/FTO对电极,研究了旋涂退火次数对Pt/FTO对电极的载铂量、透光率和组装的染料敏化太阳能电池光电性能的影响。结果表明,用5次旋涂退火的对电极组装的电池具有最佳的能量转换效率(6.78%),高于用传统的磁控溅射对电极组装的电池。基于在最佳光电性能情况下对电极的旋涂次数和载Pt量,进一步优化H2PtCl6?6H2O前驱液的浓度和使用体积。采用一步滴涂退火处理,得到了具有高透光性、低载Pt量和高的组装电池效率的Pt/FTO对电极。用此一步法制备的Pt/FTO对电极,组装成的电池能量转换效率达到6.92%。     

Pt/MWNTs催化剂的制备及其性能

以多壁碳纳米管为载体，用液相还原法制备了Pt／MWNTs催化剂，通过XRD、TEM等技术对催化剂进行了表征，并将所制催化剂组装成燃料电池，以H2、O2为反应气，测试了催化剂的性能，结果显示Pt／MWNTs催化剂具有优良的电催化活性。     

铁系元素掺杂的Pt基疏水催化剂的制备及活性研究

以炭黑为载体、乙二醇为溶剂, 利用高压微波加热法分别制备了铁系元素(即Fe、Co、Ni三种元素)掺杂的Pt基二元催化剂. 采用TEM、XRD、EDX、XPS等手段分析了催化剂的微观结构. 活性金属粒子在炭黑载体表面分布均匀; Fe、Co、Ni掺杂后, 催化剂中活性金属粒子的粒径分布变窄, 平均粒径明显减小(由4.57nm分别降低至2.17、2.41、2.55nm); 催化剂中Pt存在Pt(0)、Pt(II)、Pt(IV)三种价态. 将催化剂分散于聚四氟乙烯乳液中, 采用自然浸渍法负载于泡沫镍, 制得Pt基疏水催化剂, 考查了其对氢-水液相交换反应的催化活性. 与单一Pt基疏水催化剂相比, 过渡金属掺杂后的二元疏水催化剂对氢-水液相交换反应的催化活性明显提高. 其催化活性由高到低依次为: PtFe/C/FN>PtCo/C/FN>PtNi/C/FN>Pt/C/FN. 催化活性的提高可能主要来源于催化剂活性金属粒径的减小. 此外, H₂O分子在Fe系元素表面的解离行为也有一定的贡献.     

羟基锡酸盐载铂复合催化剂Pt/(Co,Zn)Sn(OH)6的合成及其甲醇电催化氧化性能

以羟基锡酸盐CoSn（OH）₆和ZnSn（OH）₆纳米空心立方体为前体,采用抗坏血酸作为弱还原剂,经过超声过程分别合成了羟基锡酸钴载Pt/CoSn（OH）₆和羟基锡酸锌载Pt/ZnSn（OH）₆复合催化剂,并在甲醇氧化反应（MOR）中表现出良好的性能。Pt/CoSn（OH）₆和Pt/ZnSn（OH）₆催化剂的单位质量活性分别为1 095.6 mA/mg和699.5 mA/mg,高于C载Pt（Pt/C）的594.6 mA/mg。利用XRD、SEM、TEM、XPS和电化学测试对催化剂晶体结构和性能间的关系进行了探索。CO溶出实验结果表明,羟基锡酸盐载体有利于Pt表面CO的去除,载体与Pt间的强相互作用和载体表面的大量羟基基团增强了催化剂的催化活性和CO抗毒性。此外,Pt/（Co,Zn）Sn（OH）₆催化剂中单质Pt高的相对含量也有利于提高MOR活性。通过研究载铂羟基锡酸盐电催化氧化甲醇性能,能够揭示载体结构对催化性能的影响,有助于羟基锡酸盐载铂复合催化剂在直接甲醇燃料电池（DMFCs）领域的应用。     

不同pH值下Pt-Sn/石墨烯复合材料的电催化性能

以氧化石墨烯、SnCl2、H2PtCl6和乙二醇为原料,利用多元醇一步还原法制备高负载量的Pt-Sn/石墨烯催化剂,待反应结束后对反应液加入稀HNO3进行酸处理。通过XRD、ICP、TEM及循环伏安分析不同pH值酸处理下,Pt-Sn/石墨烯催化剂形貌结构、成分和电催化性能,讨论Pt和Sn颗粒在石墨烯表面负载率变化。结果表明,不同pH值时石墨烯均为良好载体;随酸处理程度的增加,Sn含量相应增加,复合材料对乙醇的电催化活性逐渐提高。在pH值为2时,Pt和Sn金属颗粒形成最佳协同效应,催化活性提高了1.2倍。     

高性能可见光Pt/TiO_2光催化材料的制备与性能研究

以钛酸四丁酯为钛源,H2Pt Cl6·6H2O为Pt源,采用溶胶-凝胶法制备了高性能可见光Pt/Ti O2光催化材料。采用XRD和UV-Vis对制备样品进行了表征。XRD结果表明,制备Ti O2为锐钛矿相结构,Pt的加入未改变Ti O2的晶相结构,且未发现Pt的相关衍射峰。UV-Vis测试结果表明,0.6%Pt/Ti O2样品表现出较好的可见光吸收性能。在可见光条件下,以亚甲基蓝溶液为模拟污染物对Pt/Ti O2的光催化性能进行考察。实验结果表明,随Pt掺杂量增加,亚甲基蓝降解速率常数先增大后趋于平缓,0.6%Pt/Ti O2的光催化效率最高。采用XPS对Pt/Ti O2样品产生可见光催化活性的机理进行了分析。     

Sharp cubic and octahedral morphologies of poly(vinylpyrrolidone)-stabilised platinum nanoparticles by polyol method in ethylene glycol: their nucleation,growth and formation mechanisms

Pt nanoparticles (NPs) were synthesised by a modified polyol method with the addition of silver nitrate. The results showed that the specific shapes of Pt NPs were influenced by the relevant factors, which are the contents of silver nitrate, synthetic time and temperature. A small content of silver nitrate has played an important role in determining their final shapes of platinum NPs. We observed that Pt NPs in the forms of very sharp shapes such as Pt cubes, octahedrons, cuboctahedrons and tetrahedrons have been obtained. In addition, the shape growth mechanisms and formation of Pt NPs have been studied. They exist in both cubic and octahedral shapes. Importantly, Pt nanocrystals can grow into main cubic and octahedral shapes for a short time less than 15?min. Moreover, Pt nanocrystals can also grow into different shapes from cubic and octahedral into spherical ones for several hours. Especially, they exhibited interesting shapes of multiple-branched Pt nanostructures because of their overgrowth and aggregations. Clearly, large cubic and octahedral Pt NPs of 160?nm diameter were observed. The growth and formation of large cubic and octahedral Pt NPs were due to the aggregation of Pt clusters or initial Pt seeds, even small Pt nanocrystals.     

磁控溅射法制备直接甲醇燃料电池阴极

等离子体溅射沉积是制备直接甲醇燃料电池电极的非常好的方法。采用磁控溅射,Pt被成功溅射在气体扩散层上。在不同的溅射功率和气压下制备了具有相同Pt负载量(0.1mg/cm2)的电极。X射线衍射测试显示Pt以面心立方结构存在。X射线光电子能谱证明了电极中的Pt以Pt(0)态的形式存在。扫描电镜观测显示Pt催化剂以纳米粒子和纳米团簇的形式存在。溅射电极的循环伏安曲线都具有Pt金属的典型性质。将用溅射方法制备的阴极与商用催化剂制备的阳极组装成膜电极一体化,并测试了单电池的性能。结果显示,在5.3Pa,110W条件下制备的阴极相比其他溅射参数下制备的电极具有较好的电性能,这主要是由于Pt粒径的降低以及多孔催化剂层的形成。     

AuPt合金的分离及Au、Pt提纯的研究

研究了AuPt合金中Au与Pt的分离及Pt的提纯工艺,拟定了AuPt合金的分离和Pt提纯的工艺步骤,通过批量生产,获得了满意的结果.在使用还原剂将Au和Pt分离后,Au不需再提纯,其纯度可达99.9%;将Pt提纯后其纯度可迭99.99%;物料总回收率>98.6%.     

提高温度传感器测试准确性的方法

通过对常规工作用Pt100温度传感器检定规程和使用方法的分析,给出了一种提高Pt100温度传感器测试准确性的方法,经过对温度传感器的多点标定试验,利用Matlalb软件求出Pt100温度传感器的电阻与温度转换公式下的新的系数值,从而对其使用温度点作出准确修正,最后的试验数据和分析表明,该方法对提高传感器的准确性是切实可行的.     

质子交换膜燃料电池中Pt/C及Pt合金/C催化剂的衰退机制研究综述

成本和耐久性依然是制约质子交换膜燃料电池商业化发展的两大瓶颈。首先综述了质子交换膜燃料电池阴极Pt/C催化剂在实际工作条件下的降解情况,并给出了可能的降解机制。结果表明,Pt/C催化剂在实际工作条件下,尤其是在汽车应用中是不稳定的,通常无法用作燃料电池阴极催化剂。而Pt合金催化剂因具有优异的氧还原催化性能和相对较好的耐久性,被认为有望解决成本和耐久性这两大难题,因此在质子交换膜燃料电池中日益得到重视和应用。但如何改善合金催化剂的耐久性依然是一个棘手的问题,文章最后详细综述了PtxCoy合金催化剂可能的衰退机理,以及可在一定程度上提高Pt合金催化剂耐久性的Pt单层结构和Pt核壳结构,这对催化剂的合成和设计具有一定的指导意义。     

Cost‐effective Atomic Layer Deposition Synthesis of Pt Nanotube Arrays: Application for High Performance Supercapacitor

Due to the unique advantages of Pt, it plays an important role in fuel cells and microelectronics. Considering the fact that Pt is an expensive metal, a major challenging point nowadays is how to realize efficient utilization of Pt. In this paper, a cost‐effective atomic layer deposition (ALD) process with a low N₂ filling step is introduced for realizing well‐defined Pt nanotube arrays in anodic alumina nano‐porous templates. Compared to the conventional ALD growth of Pt, much fewer ALD cycles and a shorter precursor pulsing time are required, which originates from the low N₂ filling step. To achieve similar Pt nanotubes, about half cycles and 10% Pt precursor pulsing time is needed using our ALD process. Meanwhile, the Pt nanotube array is explored as a current collector for supercapacitors based on core/shell Pt/MnO₂ nanotubes. This nanotube‐based electrode exhibits high gravimetric and areal specific capacitance (810 Fg^?1 and 75 mF cm^?2 at a scan rate of 5 mV s^?1) as well as an excellent rate capability (68% capacitance retention from 2 to 100 Ag^?1). Additionally, a negligible capacitance loss is observed after 8000 cycles of random charging‐discharging from 2 to 100 Ag^?1.     

Is GSH Chelated Pt Molecule Inactive in Anti‐Cancer Treatment? A Case Study of Pt6GS4

Platinum (Pt) drugs are widely used in anti‐cancer treatment although many reports advocated that tumor cells could inactivate Pt drugs via glutathione‐Pt (GSH‐Pt) adducts formation. To date, GSH chelated Pt molecules have not been assessed in cancer treatment because GSH‐Pt adducts are not capable of killing cancer cells, which is widely accepted and well followed. In this report, endogenous biothiol is utilized to precisely synthesize a GSH chelated Pt molecule (Pt₆GS₄). This Pt₆GS₄ molecule can be well taken up by aggressive triple negative breast cancer (TNBC) cells. Subsequently, its metabolites could enter nuclei to interact with DNA, finally the DNA‐Pt complex triggers TNBC cell apoptosis via the p53 pathway. Impressively, high efficacy for anti‐cancer treatment is achieved by Pt₆GS₄ both in vitro and in vivo when compared with traditional first‐line carboplatin in the same dosage. Compared with carboplatin, Pt₆GS₄ keeps tumor bearing mice alive for a longer time and is non‐toxic for the liver and kidneys. This work opens a route to explore polynuclear Pt compound with accurate architecture for enhancing therapeutic effects and reducing systemic toxicity.     

Tuning Nanowires and Nanotubes for Efficient Fuel‐Cell Electrocatalysis

Developing new synthetic methods for the controlled synthesis of Pt‐based or non‐Pt nanocatalysts with low or no Pt loading to facilitate sluggish cathodic oxygen reduction reaction (ORR) and organics oxidation reactions is the key in the development of fuel‐cell technology. Various nanoparticles (NPs), with a range of size, shape, composition, and structure, have shown good potential to catalyze the sluggish cathodic and anodic reactions. In contrast to NPs, one‐dimensional (1D) nanomaterials such as nanowires (NWs), and nanotubes (NTs), exhibit additional advantages associated with their anisotropy, unique structure, and surface properties. The prominent characteristics of NWs and NTs include fewer lattice boundaries, a lower number of surface defect sites, and easier electron and mass transport for better electrocatalytic activity and lower vulnerability to dissolution, Ostwald ripening, and aggregation than Pt NPs for enhanced stability. An overview of recent advances in tuning 1D nanostructured Pt‐based, Pd‐based, or 1D metal‐free nanomaterials as advanced electrocatalysts is provided here, for boosting fuel‐cell reactions with high activity and stability, including the oxygen reduction reaction (ORR), methanol oxidation reaction (MOR), and ethanol oxidation reaction (EOR). After highlighting the different strategies developed so far for the synthesis of Pt‐based 1D nanomaterials with controlled size, shape, and composition, special emphasis is placed on the rational design of diverse NWs and NTs catalysts such as Pt‐based NWs or NTs, non‐Pt NTs, and carbon NTs with molecular engineering, etc. for enhancing the ORR, MOR, and EOR. Finally, some perspectives are highlighted on the development of more efficient fuel‐cell electrocatalysts featuring high stability, low cost, and enhanced performance, which are the key factors in accelerating the commercialization of fuel‐cell technology.     

Ultrahigh Mass Activity Pt Entities Consisting of Pt Single atoms,Clusters, and Nanoparticles for Improved Hydrogen Evolution Reaction

Platinum is one of the best-performing catalysts for the hydrogen evolution reaction (HER). However, high cost and scarcity severely hinder the large-scale application of Pt electrocatalysts. Constructing highly dispersed ultrasmall Platinum entities is thereby a very effective strategy to increase Pt utilization and mass activities, and reduce costs. Herein, highly dispersed Pt entities composed of a mixture of Pt single atoms, clusters, and nanoparticles are synthesized on mesoporous N-doped carbon nanospheres. The presence of Pt single atoms, clusters, and nanoparticles is demonstrated by combining among others aberration-corrected annular dark-field scanning transmission electron microscopy, X-ray absorption spectroscopy, and electrochemical CO stripping. The best catalyst exhibits excellent geometric and Pt HER mass activity, respectively ≈4 and 26 times higher than that of a commercial Pt/C reference and a Pt catalyst supported on nonporous N-doped carbon nanofibers with similar Pt loadings. Noteworthily, after optimization of the geometrical Pt electrode loading, the best catalyst exhibits ultrahigh Pt and catalyst mass activities (56 ± 3 A mg⁻¹_Pt and 11.7 ± 0.6 A mg⁻¹_Cat at −50 mV vs. reversible hydrogen electrode), which are respectively ≈1.5 and 58 times higher than the highest Pt and catalyst mass activities for Pt single-atom and cluster-based catalysts reported so far.     

Pt/介孔TiO2-SiO2的制备、表征及光催化性能研究

以正硅酸乙酯、钛酸异丙酯为前驱体，尿素为沉淀剂，改进的均匀沉淀法制备了TiO2-SiO2介孔复合材料，用XRD、FTIR、氮气吸附-脱附、XPS等对材料进行了表征．结果表明：Ti／Si摩尔比为0．5的介孔复合材料平均孔径为3．2nm，比表面积达到609m^2／g．用光还原法在材料表面沉积适量的贵金属Pt，大大提高了材料的光催化活性．