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.     

单壁碳纳米管负载Pt基二元金属催化剂对甲醇和乙醇氧化的电催化性能研究

用单壁碳纳米管（SWCNT）作为载体制备得到Pt,Pt—Fe,Pt—Co和Pt—Ni催化剂,并用循环伏安法和电化学阻抗谱法研究各催化剂对甲醇和乙醇氧化的电化学催化性能。对于甲醇和乙醇的氧化,Pt—Fe／SWCNT,Pt—Co／SWCNT和Pt—Ni／SWCNT电催化活性依次增强,抗中毒性能依次减弱。与Pt／SWCNT催...     

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。     

SnO2底层形貌对Pt／SnO2薄膜电催化氧化甲醇性能的影响

通过加入不同的有机添加剂,以电沉积一热氧化法制备了3种不同形貌的多孔SnO2薄膜,再电沉积Pt,制备得到不同形貌的多孔Pt／SnO2薄膜。通过扫描电镜（SEM）、x射线衍射（XRD）和循环伏安（CV）法分析了薄膜的形貌、结构和电催化氧化甲醇的活性。结果表明,不同形貌的多孔Pt／SnO2薄膜具有不同的电催化性能：SnO2镀液中添加聚乙二醇辛基苯基醚（OP,1．0mL／L）和苯甲醛（25mg／L）,制得的SnO2薄膜呈一定规则排列的长条状,经氧化和电沉积Pt后的多孔Pt／SnO2薄膜具有良好的电催化氧化甲醇的活性及耐CO的性能。     

石墨烯支持Pt纳米粒子修饰电极的制备及电催化活性研究

采用一步电化学法制备了石墨烯支持Pt纳米粒子修饰电极(Nano-Pt/ERGO/GCE),利用交流阻抗研究了电极的性能以及该修饰电极的电催化活性。结果表明,采用循环伏安法制备石墨烯支持Pt纳米粒子,具有制备方法简单且纳米粒子粒径可控等优点。与单独的Pt纳米粒子修饰电极相比,Nano-Pt/ERGO/GCE电极表面Pt粒子分布更均匀,对甲醇的氧化具有极强的电催化活性。研究成果在甲醇燃料电池的研发中具有潜在的应用价值。     

Pt/ZrP-Th-CNTs复合催化剂的制备及其对甲醇的电催化氧化

利用硫堇(Th)和碳纳米管(CNTs)对磷酸锆(ZrP)改性,并以改性的ZrP复合材料作为催化剂载体,采用化学还原法制备得到Pt/ZrP-Th-CNTs复合催化剂.SEM研究结果表明,金属铂(Pt)微粒在载体表面具有很高的分散度,且颗粒大小均匀,电极的比表面积也得到较大提高.考察了复合电极在酸性介质中对甲醇的电催化氧化...     

{H3[PMo12O40]/Pt/PAMAM}复合膜的制备及对甲醇的电催化氧化

采用循环伏安法在玻碳电极上制备了{H3[PMo12O40]/Pt/PAMAM}复合膜,用X射线光电子能谱(XPS)、扫描电子显微镜(SEM)、电子能谱技术(EDS)、原子力显微镜(AFM)和循环伏安法(CV)研究了膜的组成、形貌及其对甲醇的电催化氧化活性。结果表明,Pt纳米粒子在PAMAM基底上分散均匀;最外层沉积H3[PMo12O40]后,与相同条件下制备的Pt/PAMAM膜相比,{H3[PMo12O40]/Pt/PAMAM}复合膜修饰电极对甲醇的氧化有更强的电催化活性。     

Pt-TiO2纳米管电极的制备及电催化性能

采用电化学阳极氧化-阴极还原法制备Pt-TiO2纳米管电极.扫描电镜(SEM)结果显示TiO2纳米管平均管径100nm,管长470nm,管壁厚20nm,且其比表面积大,同时纳米Pt微粒分散在TiO2纳米管上,且粒径细小,Pt微粒充分裸露,使得Pt-TiO2纳米管电极活性点多,电催化性能高.对甲醇的电催化性能测试表明:同纯Pt电极和Pt-TiO2电极(Pt微粒固定在TiO2致密膜上)相比,Pt-TiO2纳米管电极对甲醇具有更高的电催化活性,其氧化峰电流密度是在纯Pt片电极上的20倍以上.     

Pt/TiO2-NTs复合材料的制备及其甲醇电氧化机理研究

采用水热法合成锐钛矿型TiO2纳米管(TiO2-NTs),并以其为载体制备了Pt/TiO2-NTs复合材料。用TEM、XRD对复合材料的形貌和结构进行了表征,TEM测试表明Pt纳米粒子以簇状形式均匀地分散在TiO2纳米管表面。运用循环伏安法研究了Pt/TiO2-NTs复合材料在不同条件下对硫酸中甲醇的电催化活性,并讨论了甲醇的电氧化机理。结果表明,Pt/TiO2-NTs复合材料具有出色的电催化活性。因此,TiO2-NTs被认为是非常有潜力的燃料电池贵金属催化剂载体材料。     

不同pH值对直接乙醇燃料电池Pt-SnO2/C 电催化性能的影响

采用水热法制备了高分散Pt-SnO2/C电催化剂,对制备工艺进行了最佳优化,考察了不同反应溶液pH值对电催化剂活性的影响。采用XRD、SEM、TEM、比表面积、粒度分析等手段对催化剂进行了结构表征。制备的Pt-SnO2纳米复合颗粒高度分散在活性炭载体表面,其平均粒径约4.5nm。通过循环伏安、计时电流、交流阻抗等技术测试了电极在乙醇体系中的电催化活性。结果表明,随着反应溶液pH值的增加,制备的Pt-SnO2/C催化剂可使乙醇的氧化发生在较低电位。在pH值为9、铂锡原子比为3∶1时,制备的Pt-SnO2/C复合催化剂,可以得到较高的乙醇氧化电催化活性和电化学长期稳定性,氧化峰电流密度高达104.54mA·cm-2。     

Electrochemical characterization of Pt-Ru-Pd catalysts for methanol oxidation reaction in direct methanol fuel cells

PtRuPd nanoparticles on carbon black were prepared and characterized as electrocatalysts for methanol oxidation reaction in direct methanol fuel cells. Nano-sized Pd (2-4 nm) particles were deposited on Pt/C and PtRu/C (commercial products) by a simple chemical reduction process. The structural and physical information of the PtRuPd/C were confirmed by TEM and XRD, and their electrocatalytic activities were measured by cyclic voltammetry and linear sweep voltammetry. The catalysts containing Pd showed higher electrocatalytic activity for methanol oxidation reaction than the other catalysts. This might be attributed to an increase in the electrochemical surface area of Pt, which is caused by the addition of Pd; this results in increased catalyst utilization.     

Effect of ceria on carbon supported platinum catalysts for methanol electrooxidation

Pt–CeO₂/C catalysts were synthesized by a one-step microwave polyol process and compared with Pt/C (E-TEK) catalyst in terms of the electrochemical activity for methanol oxidation using the cyclic voltammetry and chronoamperometry. The results demonstrated that Pt–CeO₂/C catalysts exhibited lower onset potential, higher current peak and better stability for methanol electrooxidation than Pt/C (E-TEK) catalyst. The effect of ceria on the catalytic activity was investigated by electrochemical measurements and the highest electrochemical activity was obtained at the molar ratio of Pt to Ce by 2:1. The preliminary mechanism of the enhanced electrocatalytic performance for methanol oxidation was discussed.     

Microwave-assisted synthesis of high-loading, highly dispersed Pt/carbon aerogel catalyst for direct methanol fuel cell

A Pt supported on carbon aerogel catalyst has been synthesized by the microwave-assisted polyol process. The Pt supported on carbon aerogel catalyst was characterized by high resolution transmission electron microscopy and X-ray diffraction. The results show a uniform dispersion of spherical Pt nanoparticles 2·5–3·0 nm in diameter. Cyclic voltammetry and chronoamperometry were used to evaluate the electrocatalytic activity of the Pt/carbon aerogel catalyst for methanol oxidation at room temperature. The Pt/carbon aerogel catalyst shows higher electrochemical catalytic activity and stability for methanol oxidation than a commercial Pt/C catalyst of the same Pt loading.     

Microwave polyol synthesis of Pt/C catalysts with size-controlled Pt particles for methanol electrocatalytic oxidation

Pt/C catalysts with different mean size of Pt particles were prepared by a microwave-assisted polyol process and characterized by TEM and XRD. The effects of the synthesis solution pH on Pt particles size and distribution, and their activity for methanol electrooxidation were investigated. Pt nanoparticles were small and uniform with mean size of 2.7 nm under the pH of 9.5. Pt/C catalyst showed high activity for methanol electrooxidation.     

Template-directed synthesis of nitrogen- and sulfur-codoped carbon nanowire aerogels with enhanced electrocatalytic performance for oxygen reduction

Heteroatom doping,precise composition control,and rational morphology design are efficient strategies for producing novel nanocatalysts for the oxygen reduction reaction (ORR) in fuel cells.Herein,a cost-effective approach to synthesize nitrogen-and sulfur-codoped carbon nanowire aerogels using a hard templating method is proposed.The aerogels prepared using a combination of hydrothermal treatment and carbonization exhibit good catalytic activity for the ORR in alkaline solution.At the optimal annealing temperature and mass ratio between the nitrogen and sulfur precursors,the resultant aerogels show comparable electrocatalytic activity to that of a commercial Pt/C catalyst for the ORR.Importantly,the optimized catalyst shows much better long-term stability and satisfactory tolerance for the methanol crossover effect.These codoped aerogels are expected to have potential applications in fuel cells.     

Electrocatalytic activity of PtAu/C catalysts for glycerol oxidation

The electrocatalytic oxidation of glycerol on PtAu/C catalysts has been investigated by cyclic voltammetry. PtAu bimetallic nanoparticles are prepared by chemical reduction. Carbon-supported PtAu catalysts are found to exhibit high electrocatalytic activity for the oxidation of glycerol in alkaline solution in terms of oxidation potential and current density as well as stability, and PtAu/C catalysts with different Pt:Au composition ratios show no much difference in catalytic activity. In acidic solution, PtAu/C catalysts exhibit similar to Pt/C catalysts in activity, but the advantage of the PtAu/C catalysts in terms of per unit mass of platinum is still obvious. The PtAu/C catalysts, in a wide Pt:Au ratio range, show a remarkable enhancement in the mass specific activity of platinum with decreasing platinum content in both alkaline and acidic solutions. This is of significance for reducing the usage of platinum and indicates that though platinum acts as main active sites, gold also plays an important role in the function of PtAu/C catalysts.     

介孔碳化钨负载铂催化剂对甲醇氧化的电催化性能

采用硬模板法制备了介孔碳化钨(m-WC), 进一步还原铂的前驱体(H2PtCl6)得到Pt/m-WC催化剂。采用X射线粉末衍射(XRD)、透射电子显微镜(TEM)和X射线光电子能谱(XPS)等测试手段对样品的物相、结构和形貌进行了表征。结果表明, 所制得的m-WC载体为单一的碳化钨相, 孔径为10~20 nm, Pt/m-WC催化剂中Pt的粒径约为3.4 nm, 主要以金属态形式存在, 相对比较均一的Pt纳米粒子均匀地分散在载体的表面和孔道中。电化学测试结果表明, 与普通WC载Pt催化剂(Pt/c-WC)相比, Pt/m-WC催化剂具有较大的电化学活性表面积, 对甲醇呈现出更高的电催化氧化活性和更好的稳定性。     

Simple approach to synthesis Pt/NiO flower microspheres and their electrocatalytic properties

A kind of novel Pt/NiO flower microsphere structure has been successfully fabricated through a two step chemical process. Firstly NiO flower microspheres could be prepared by a hydrothermal method with the assistance of biomolecule (l-glutamic acid). Secondly the Pt/NiO microsphere composition could be synthesized by the reduction of H₂PtCl₆ solution by use of glucose, and the as-deposited Pt nanoparticles with less than 40 nm in size were embedded into the gaps of the adjacent petals. The sample was characterized by XRD, SEM, TEM, EDS et al. This new kind of structure shows excellent electrocatalytic properties compared with that of Pt nanoparticles, which might provide an efficient way to improve the electrocatalytic property of nanomaterials and other applications.