α-MoC/石墨烯复合材料的氧还原性能及其在微生物燃料电池中的应用

用改良Hummers法和碳热还原法分别制备了石墨烯和碳化钼。用扫描电子显微镜和XRD表征了材料的形貌和结构。用循环伏安和线性扫描测试了材料的氧还原催化性能,结果发现,复合材料的氧还原峰电流和起峰电位均大大优于单一材料,表现出较好的催化性能。含有12mg/cm~2α-MoC碳化钼/石墨烯复合材料作为阴极催化剂的MFCs最大功率密度为417.6m W/m~2,达到商业铂碳的68.2%。因此,廉价的α-MoC/石墨烯复合材料作为MFCs阴极氧还原催化剂具有巨大的应用潜力。     

多孔石墨烯基酞菁铁复合物的制备及其电催化氧还原性能研究

利用溶剂热法制备多孔石墨烯,然后超声处理将酞菁铁修饰在多孔石墨烯表面,制备出多孔石墨烯基酞菁铁复合物用于碱性介质氧还原。利用循环伏安法和线性扫描伏安法考察该复合物的催化氧还原的能力,结果显示:多孔石墨烯基酞菁铁复合物修饰电极比多孔石墨烯修饰电极表现出更正的还原电位,具有更高的催化活性。     

MoO_3/石墨烯/碳纳米管复合阴极在MFCs中的应用

采用简单的水热合成法制备了氧化钼(MoO_3)/石墨烯(GNS)/碳纳米管(CNT)复合材料。用扫描电子显微镜(SEM)和X射线衍射仪(XRD)表征了材料的形貌和结构。用循环伏安(CV)和线性扫描(LSV)测试了材料的氧还原催化性能,结果发现,复合材料的氧还原电流和起始电位均大大优于单一的MoO_3,表现出较好的催化性能。含有3mg·cm~(-2) MoO_3/GNS/CNT复合材料作为阴极催化剂的MFC最大功率密度为510 m W·m~(-2),达到商业铂碳的83%。因此,廉价的MoO_3/GNS/CNT复合材料作为MFC阴极氧还原催化剂具有巨大的应用潜力。     

电合成法制备纳米材料及纳米材料电极上的电催化合成

通过电化学合成前驱体直接水解法制备纳米TiO2 粉体和纳米TiO2 膜电极。用循环伏安法、循环方波伏安法和电解合成法研究了纳米TiO2 膜电极对有机合成反应的电催化活性。发现纳米TiO2 膜电极在 0 2～ - 1 2V扫描电位区间有两对氧化还原峰 (峰电位Epc1=- 0 5 6V ,峰电位Epc2 =- 0 95V ,扫描速度 10 0mV·s-1) ,具有异相氧化还原催化行为。电解结果表明 ,纳米TiO2 膜中的Ti(Ⅳ ) /Ti(Ⅲ )氧化还原电对作为媒质 ,异相间接电还原硝基苯为对氨基苯酚 (收率91 6 % ,电流效率 95 2 % )和草酸为乙醛酸 (收率 96 5 % ,电流效率 90 % )。     

聚苯胺/钯纳米复合材料的原位还原法制备及表征

本文采用原位还原法,利用聚苯胺本身的还原性,对硝酸钯进行了还原和负载,制得了聚苯胺/钯纳米复合材料,考察了掺杂态及脱掺杂态聚苯胺对原位还原反应的影响,通过红外光谱、紫外光谱、扫描电镜和X射线衍射对所得复合材料的结构进行了表征,并用循环伏安法测定了复合材料对甲酸的催化性能。结果表明所制备的复合材料对甲酸具有一定的催化性能,且脱掺杂态聚苯胺复合材料的性能要优于掺杂态聚苯胺复合材料的性能。     

介孔炭/铂纳米粒子复合材料修饰电极的制备及其应用

本文利用介孔炭的吸附性制备了介孔炭/铂纳米粒子的复合材料修饰电极,然后用循环伏安法,用该电极测定对苯二酚。结果显示对苯二酚溶液在裸玻碳电极上的峰电流最小,然后是介孔炭修饰电极,复合材料修饰电极的峰电流最大,表明铂纳米粒子对对苯二酚溶液有很好的催化性。复合材料修饰电极在1.0×10~(-5)~1.0×10~(-3) mol/L范围内的对苯二酚溶液中浓度c与峰电流ip有良好的线性关系。     

介孔炭修饰玻碳电极的制备及其分析特性研究

利用硼氢化钠的还原性从氯铂酸钾溶液中还原出了纳米铂,然后利用介孔炭的吸附性制备了介孔炭/纳米铂离子复合电极材料,用该复合材料制备了介孔炭/铂纳米粒子复合修饰电极。经过实验研究发现,介孔炭/铂纳米粒子复合修饰电极对过氧化氢有电催化作用,过氧化氢在该修饰玻碳电极上可产生较大的还原峰电流,表明介孔炭/铂纳米粒子对过氧化氢有很好的催化性能,据此建立了过氧化氢的电化学分析方法。     

MoO3/石墨烯/碳纳米管复合阴极在MFCs中的应用

采用简单的水热合成法制备了氧化钼（MoO₃）/石墨烯（GNS）/碳纳米管（CNT）复合材料。用扫描电子显微镜（SEM）和X射线衍射仪（XRD）表征了材料的形貌和结构。用循环伏安（CV）和线性扫描（LSV）测试了材料的氧还原催化性能,结果发现,复合材料的氧还原电流和起始电位均大大优于单一的MoO₃,表现出较好的催化性能。含有3 mg·cm^-2 MoO₃/GNS/CNT复合材料作为阴极催化剂的MFC最大功率密度为510 mW·m^-2,达到商业铂碳的83%。因此,廉价的MoO₃/GNS/CNT复合材料作为MFC阴极氧还原催化剂具有巨大的应用潜力。     

甲醇在碳载纳米Pt电极上的电化学研究

应用循环伏安法制备了nano-Pt/GC修饰电极,优化了铂微粒在电极表面的沉积条件,并用扫描电子显微镜(SEM)和在硫酸中的循环伏安曲线对其进行了表征。结果表明铂微粒较为均匀地分散在玻碳电极表面,粒径约为140nm,电极具有很大的比表面积。循环伏安实验结果表明nano-Pt/GC电极对甲醇电氧化的催化活性明显高于铂片电极,在该修饰电极上甲醇正向扫描和反向扫描时的氧化峰电位分别是0.67V和0.49V,峰电流为61.00mA/cm2和50.50mA/cm2,分别是铂片电极上的3.13倍和3.10倍,有效地提高了金属铂的利用率,铂微粒在电极表面的最佳沉积条件是循环次数为100次和沉积速度为5mV/s。     

石墨烯基钴卟啉复合物的制备及其电催化氧气还原性能研究

通过简单的水热反应实现石墨烯(graphene)和钴卟啉(Co TPP)的复合,制备出石墨烯基钴卟啉复合物(Co TPP-graphene),以透射电镜表征其形貌,循环伏安法(cyclic voltammogram,CV)考察其催化氧还原的能力。结果表明:在中性介质中,Co TPP-graphene比graphene和Co TPP单独修饰的电极的氧还原电位更正,还原电流更大,催化氧还原的性能更好。     

Evaluation of the Performance of Platinum Nanoparticle–Titanium Oxide Nanotubes as a New Refreshable Electrode for Formic Acid Electro‐oxidation

Platinum nanoparticles (Pt‐NP) are deposited on the surface of titanium oxide nanotubes (TN) by microemulsion method. Highly ordered TN on a pure titanium substrate are successfully fabricated by anodizing of titanium. The morphology and surface analysis of Pt‐NP/TN electrodes were investigated using scanning electron microscopy and X‐ray diffraction spectroscopy, respectively. The electro‐oxidation of formic acid on Pt‐NP/TN electrodes in acidic medium was studied by cyclic voltammetry and chronoamperometry methods. The results showed that the oxidation peak currents on the Pt‐NP/TN electrode for formic acid oxidation are several times larger than a smooth platinum electrode and confirmed the better electro‐catalytic activity and stability of these new electrodes. The photocatalytic properties of titanium oxide make the Pt‐NP/TN electrode reusable after a short UV treatment, and the electro‐oxidation current density of Pt‐NP/TN electrode after UV‐cleaning can be re‐established. So Pt‐NP/TN electrode has a good application potential to fuel cells.     

Microwave-assisted synthesis and pulse electrodeposition of palladium nanocatalysts on carbon nanotube-based electrodes

The deposition of Pd nanoparticles prepared by microwave-assisted synthesis (MS) and pulse electrodeposition (PE) on networks of multiwall carbon nanotubes (CNTs) was investigated. The CNTs were grown directly on microscaled carbon paper using catalytic chemical vapor deposition. Both MS and PE methods enabled the quick formation of nanosized Pd particles over a CNT surface without any additional thermal reduction. Cyclic voltammetry and electrochemical impedance spectroscopy were used to examine the electrochemical behavior of the Pd catalysts. The Pd catalyst prepared with the MS method not only offers a higher active coverage for adsorption/desorption of hydrogen but also a more stable durability toward acid electrolytes when compared with that of the catalyst prepared with the PE method. The electrochemical surface area of the Pd catalyst was approximately 1.38 times than that of the Pt catalyst, which was also prepared with MS method. The equivalent series resistance for all the catalyst electrodes was kept between 2.07 and 2.25 Ω after potential cycling. Based on the results, the Pd catalyst is found to be a feasible alternative to the Pt catalyst because of its low cost, durability, and high catalytic activity.     

Pt修饰的Pd/石墨烯纳米复合材料的制备及对乙二醇氧化反应的电催化活性

以氧化石墨(GO)和Pd(NO₃)₂为原料,通过化学还原法制备Pd纳米粒子-石墨烯(Pd/G)纳米复合材料,然后以H₂PtCl₆作为Pt前体,在Pd纳米粒子的表面恒电位沉积Pt,制备不同Pt负载量的Pd/G(Pt-Pd/G)电极.利用场发射扫描电镜(FE-SEM)、透射电镜(TEM)和X射线能谱仪(EDX)对材料的微观结构进行了表征和分析.结果显示石墨烯上的金属粒子分散均匀,平均粒径约7.2nm.电化学测试结果显示Pt-Pd/G电极对乙二醇电化学氧化反应具有良好的催化性能.当纳米粒子的Pt:Pd原子百分比为1:42时,其反应峰电流密度分别为Pd/G和Pt/G电极的3.0倍和2.7倍.少量的Pt沉淀可显著改进Pd/G电极的催化活性.本研究采用的修饰方法简单,修饰效果明显,可应用于其他金属纳米复合材料的异金属修饰.     

碳纳米管表面Pd纳米颗粒对甲醇的电催化氧化研究

采用电化学循环伏安法分别在碳纳米管(CNT)和玻碳(GC)电极表面沉积Pd纳米颗粒。扫描电镜(SEM)和XRD分析显示了Pd纳米颗粒均匀分散于碳纳米管表面,而在GC表面则趋向于堆积形成Pd金属薄膜。比较研究了Pd/CNT和Pd/GC电极在碱液中对甲醇的电催化氧化性能,循环伏安结果发现,Pd/CNT对甲醇的催化活性要高于Pd/GC电极;而交流阻抗谱研究发现,Pd/CNT电极对甲醇具有更快的催化氧化速率。另外,不同Pd载量,不同环境温度以及不同甲醇浓度的研究表明,相对于Pd/GC电极,Pd/CNT电极对甲醇的催化氧化具有更高的灵敏度和电化学稳定性。     

碳纳米管上电沉积钯对乙醇的电催化氧化研究

采用电化学循环伏安法沉积Pd纳米颗粒,在碳纳米管(CNT)电极表面获得了粒径约为20 nm而且分散性良好的Pd纳米颗粒,而玻碳(GC)电极表面上Pd纳米颗粒趋向于堆积形成紧密的Pd金属薄膜。研究发现,在碱液中Pd/CNT电极对乙醇的催化活性要高于Pd/GC电极,而交流阻抗实验发现,Pd/GC电极的阻抗半圆明显大于碳纳米管,表明了Pd/CNT电极对乙醇的催化速率明显优于Pd/GC电极。不同Pd载量以及环境温度影响实验发现,Pd/CNT电极上峰电流的增长速率要明显大于Pd/GC电极,而不同乙醇浓度实验进一步表明,Pd/CNT电极对于乙醇浓度的响应要比Pd/GC的灵敏。     

Enhancement of oxygen reduction activity by sequential impregnation of Pt and Pd on carbon support

Two Pd-based PtPd bimetallic catalysts (mole ratio of Pt to Pd=1: 18) were prepared by co-impregnation (Pt-Pd/C) and sequential impregnation of Pt on Pd/C [Pt(Pd/C)] for the application to oxygen reduction reaction (ORR). The prepared bimetallic catalysts had lower ORR activities than Pt/C, while they showed largely enhanced activity compared to Pd/C. In particular, the extent of enhancement was found to be dependent on the surface composition. The observed mass and specific activities of Pt(Pd/C) were more than two times higher than those of Pt-Pd/C. The superior activity of Pt(Pd/C) observed from the performed studies was attributed to its Pt-rich surface.     

Pt and Pd decorated Au nanowires: Extremely high activity of ethanol oxidation in alkaline media

Highly ordered Pt and Pd decorated Au nanowire arrays, Pt/Au NWA and Pd/Au NWA, are prepared by anodized aluminum oxide (AAO) template based electrodeposition combined with chemical reduction. The effect of shell material on the ethanol oxidation currents is studied. The maximum current densities are several times higher on the modified electrodes than on the unmodified Pt (Pd) NWA. The most highly active electrode shows almost 4-fold increase in the ethanol peak current. Pt/Au and Pd/Au NWA electrodes show a similar dependence of the ethanol oxidation current density on the Pd or Pt deposition time, which most likely, reflects the optimal upper layer thickness. The synergistic effect between substrate and deposit materials seems to be the most important factor explaining such unusually high activity.     

An efficient reduction route for the production of Pd–Pt nanoparticles anchored on graphene nanosheets for use as durable oxygen reduction electrocatalysts

Pt and Pd–Pt nanoparticles were anchored on reduced graphene oxide (RGO) with the aid of poly(diallyldimethylammonium chloride) (PDDA), where Pt and Pd ions were first attached to PDDA-functionalized graphene oxide sheets and the encased metal ions and graphene oxide were then reduced simultaneously by ethylene glycol. As supported by transmission electron microscopy, metal nanoparticles, of small particle size even at a high metal loading, were chemically attached to PDDA–RGO. X-ray diffraction indicates that the as-prepared Pd–Pt nanoparticles have a single-phase fcc structure and are principally alloys of Pd and Pt. Among the RGO-supported Pt and Pd–Pt catalysts, Pt nanoparticles anchored on PDDA–RGO exhibit the highest activity for the oxygen reduction reaction (ORR), and the ORR activity of the Pd–Pt alloy electrocatalysts increases with Pt content. All the catalysts demonstrate an enhanced ORR durability when PDDA is present; strongly suggesting that PDDA plays a crucial role in the dispersion and stabilization of the metal nanoparticles on RGO. The ORR activities of the Pd–Pt catalysts remain enhanced even after accelerated durability testing. The formation of a Pt-rich shell, as confirmed by X-ray photoelectron spectroscopy and CO stripping voltammetry, may account for the increased activity.     

纳米TiO_2-Pt修饰电极上甲醇的电催化氧化研究

用电化学法合成前驱体Ti(OEt)4,经直接水解法制备纳米TiO2膜,通过直接在纳米TiO2膜上电沉积Pt微粒得到纳米TiO2 Pt复合催化电极。扫描电子显微镜(SEM)和X射线衍射(XRD)分析结果表明,纳米TiO2的晶形为锐钛矿型,粒径约30nm,电沉积纳米Pt粒子(平均粒径约60nm)均匀地分散在纳米TiO2膜表面。循环伏安和计时电位测试表明,纳米TiO2 Pt修饰电极对甲醇的电氧化具有高催化活性和稳定性,Pt载量为0 68mg/cm2时,室温下甲醇氧化电流达到190mA/cm2,是纯Pt电极上的7 6倍。