铂基合金纳米材料的可控合成及其催化性能研究

发布时间：2018-04-08 07:39

本文选题：铂基纳米催化剂　切入点：多孔/中空结构　出处：《安徽师范大学》2017年硕士论文

【摘要】：传统化石燃料的日益枯竭,环境污染的持续加重,迫使人们大力探索新的清洁能源。燃料电池以其高效的能量利用率,清洁的产物排放日益受到各行业的关注与青睐。然而作为燃料电池的技术关键及成本关键的铂基催化剂的催化性能仍不能胜任大规模商业化使用的需要。所以我们迫切的需要研发出具有高催化性能的铂基催化剂。本文就多孔/中空状铂基纳米催化剂的设计,可控合成及催化性能做了研究。以期能制备出具有高活性、高稳定性的铂基纳米催化剂,以降低燃料电池中铂的使用量,降低燃料电池的成本,最终达到商业化大规模使用燃料电池的目的。具体工作内容如下:1.利用温和的种子成长法合成多孔PtAg合金纳米颗粒。该铂基纳米颗粒可通过调节成长液中Ag NO3与H2Pt Cl6加入量的比值,实现纳米颗粒的形貌由多圆角花瓣状至多尖角八面体状的可控合成,同时产物纳米颗粒中的Pt/Ag原子数比从3.17(Pt76Ag24)变至1.94(Pt66Ag34)。实现了对铂基催化剂形貌及组分的同时调节。对硝基苯酚的催化还原及电催化氧化甲醇的性能测试显示Pt Ag合金纳米颗粒,尤其是多孔八面体Pt70Ag30纳米颗粒,展现出极高的催化活性及稳定性。这提示了我们可以通过同时调控Pt基纳米颗粒的形貌与组分,来提升Pt基纳米颗粒的催化性能。2.利用PdCl42-与PtCl62-还原反应速率的差异及后续空气的氧化刻蚀,制备出了多孔树突状PtPd双金属纳米颗粒,多孔空心樱花状PtPd合金纳米颗粒及多孔笼状PtPd合金纳米颗粒,并通过控制Pd前驱体投入量等因素实现了空心纳米颗粒孔经,壳层厚度以及元素组成的调节。得到的PtPd双金属纳米颗粒具有十分优异的甲醇电化学氧化催化活性,其中碳负载的多孔中空樱花状Pt32Pd68纳米颗粒具有超好的电催化稳定性,在循环测试1000次后仍能保持96.69%的电催化活性。
[Abstract]:The depletion of traditional fossil fuels and the worsening of environmental pollution force people to explore new clean energy sources.Fuel cells are attracting more and more attention for their high energy efficiency and clean emission.However, as the key technology and cost of fuel cells, platinum-based catalysts still can not meet the needs of large-scale commercial use.Therefore, we urgently need to develop platinum-based catalysts with high catalytic performance.In this paper, the design, controllable synthesis and catalytic performance of porous / hollow platinum-based nanocatalysts were studied.In order to prepare high activity and high stability platinum based nanometer catalyst can reduce the use of platinum in fuel cell and reduce the cost of fuel cell and finally achieve the purpose of commercial use of fuel cell on a large scale.The details of the work are as follows: 1.Porous PtAg alloy nanoparticles were synthesized by mild seed growth method.By adjusting the ratio of Ag NO3 to H2Pt Cl6 in the growth solution, the platinum based nanoparticles can be synthesized by controllable synthesis of polypetal shape and octahedron at most.At the same time, the ratio of Pt/Ag atoms in the nanoparticles was changed from 3.17 渭 m Pt76Ag24) to 1.94 Pt66Ag34 渭 mol 路mol ~ (-1) 路mol ~ (-1) 路min ~ (-1).The morphology and composition of platinum based catalyst were adjusted simultaneously.Catalytic reduction of p-nitrophenol and electrocatalytic oxidation of methanol showed that Pt-Ag alloy nanoparticles, especially porous octahedral Pt70Ag30 nanoparticles, exhibited very high catalytic activity and stability.This suggests that we can improve the catalytic performance of Pt based nanoparticles by simultaneously regulating the morphology and composition of Pt-based nanoparticles.The porous dendritic PtPd bimetallic nanoparticles, porous hollow cherry blossom PtPd alloy nanoparticles and porous cage PtPd alloy nanoparticles were prepared by using the difference in the rate of reduction reaction between PdCl42- and PtCl62- and the subsequent air oxidation etching.The pore path, shell thickness and element composition of hollow nanocrystalline particles were adjusted by controlling the amount of PD precursor input.The obtained PtPd bimetallic nanoparticles have excellent catalytic activity for methanol electrochemical oxidation. The carbon supported porous hollow Cherry cherry (Pt32Pd68) nanoparticles have excellent electrocatalytic stability.The electrocatalytic activity of 96.69% was maintained after 1000 cycles.
【学位授予单位】：安徽师范大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36;TB383.1

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