铂基纳米材料的制备及其电催化性能研究

发布时间：2018-06-17 22:50

本文选题：Pt基催化剂 + PtIr合金　；参考：《吉林大学》2017年硕士论文

【摘要】：Pt作为一种具有优异性能的电化学催化材料,广泛应用于工业催化、航天、电子、科学研究等多个领域。电化学催化作为催化反应中非常重要的组成部分,在燃料电池汽车、有机污染物降解、生物传感器、一氧化碳氧化、二氧化碳电催化还原、工业电解水制氢、工业电解水制氧等众多方面都具有非常重要的应用。Pt贵金属在地壳中的含量相对比较稀少(约为0.001 ppm),但是它在许多电催化反应中占有不可或缺的地位。因此,如何简单有效的制备出更加高效的Pt基电催化剂,仍然是许多材料科学家十分关注的课题。提升Pt电催化活性的主要目的就是提升其单位质量下能提供的催化电流数值。目前商业化的Pt/C在电催化反应中存在催化活性不足、稳定性差及催化剂易于中毒等问题,严重制约了Pt作为电催化材料的商业化应用之路。无论作为燃料电池高效的阳极催化剂还是作为电催化析氢的催化剂,Pt都占有非常重要的地位。本文针对Pt催化剂活性不足的问题,从将Pt与Ir进行合金化并制备出多枝状合金纳米粒子和制备低载量的Pt修饰在3D碳纸基底上两个角度出发,来提升Pt的单位质量利用效率。并将其分别应用于电催化乙二醇反应(EGOR)和电化学分解水析氢反应(HER)中。主要工作如下:(1)利用一步合成的方法在纯油胺(OA)体系中,将油胺作为溶剂、还原剂、稳定剂及结构导向剂,合成出具有较小尺寸的多枝状Pt Ir合金纳米材料。探究了Pt与Ir前驱体盐用量对材料形貌及电催化性质的影响。实验结果表明当Pt:Ir投料比为1:3,200°C下反应4 h时,所生成的小尺寸Pt Ir合金纳米材料对乙二醇的电催化活性在峰电流密度上对比商业Pt/C提升了4倍,i-t稳定性及抗一氧化碳(CO)中毒性能等方面也均有很大的提升。(2)利用电化学沉积的方法在3D碳纸基底上制备出低载量Pt修饰的材料。通过控制电化学沉积参数并使用CO作为电化学沉积气氛,制备出负载量为0.047%的低载量Pt。从结构的方面入手,制备低载量修饰的Pt以提高Pt原子的利用率。实验结果表明在CO气氛下,电化学沉积电位为-0.7 V(vs.Ag/Ag Cl),沉积时间为300 s时可制备出没有大纳米团簇存在的低载量Pt纳米结构。经过电化学分解水析氢反应的测试显示,在3D碳纸基底上制备的低载量Pt材料比商用Pt/C在-0.1 V(vs.RHE)电位下的HER质量电流密度提升了4.2倍。
[Abstract]:As an excellent electrochemical catalytic material, Pt has been widely used in many fields, such as industrial catalysis, aerospace, electronics, scientific research and so on. Electrochemical catalysis as a very important component of catalytic reactions in fuel cell vehicles, organic pollutant degradation, biosensor, carbon monoxide oxidation, carbon dioxide electrocatalytic reduction, industrial electrolytic water hydrogen production, Industrial electrolytic water for oxygen production has very important applications. The content of Pt precious metals in the crust is relatively rare (about 0.001 ppm), but it plays an indispensable role in many electrocatalytic reactions. Therefore, how to prepare more efficient Pt-based electrocatalysts is still a hot topic for many material scientists. The main purpose of enhancing Pt electrocatalytic activity is to increase the value of catalytic current provided by Pt per unit mass. At present, the commercial PT / C has some problems such as insufficient catalytic activity, poor stability and easy poisoning of catalyst, which seriously restricts the commercial application of Pt as an electrocatalytic material. Both as a highly efficient anode catalyst for fuel cells and as a catalyst for hydrogen evolution, Pt plays a very important role. In order to improve the unit mass utilization efficiency of Pt, this paper aims at improving the utilization efficiency of Pt by alloying Pt with ir and preparing multi-branched alloy nanoparticles and preparing low-load Pt modification on 3D carbon paper substrate. It has been applied to the electrocatalytic ethylene glycol reaction (EGOR) and the electrochemical decomposition of water hydrogen evolution reaction (Herr), respectively. The main work is as follows: (1) using the one-step synthesis method in the pure oil-amine (OAA) system, the multi-branched Pt ir alloy nanomaterials with small size have been synthesized by using oleamine as solvent, reductant, stabilizer and structural guide agent. The effects of the amounts of Pt and ir precursor salts on the morphology and electrocatalytic properties of the materials were investigated. The experimental results show that when the feed ratio of PT: ir is 1: 3200 掳C, the reaction time is 4 h. The electrocatalytic activity of the small size Pt ir alloy nanomaterials for ethylene glycol is 4 times higher than that of commercial Pt / C in peak current density, and the stability of PtIr alloy is 4 times higher than that of commercial Pt / Ir alloy, and the resistance to CO poisoning is also greatly improved. Low loading Pt modified materials were prepared on 3D carbon paper substrate by electrochemical deposition. By controlling the electrochemical deposition parameters and using CO as the electrochemical deposition atmosphere, a low loading amount (PT) of 0.047% was prepared. In order to improve the utilization of Pt atoms, Pt with low loading was prepared from the aspect of structure. The experimental results show that the low loading Pt nanostructures with no large nanoclusters can be prepared under CO atmosphere with electrochemical deposition potential of -0.7 V / Ag / Cl _ (1) and deposition time of 300 s. The electrochemical decomposition of water hydrogen evolution reaction showed that the mass current density of the low loading Pt material prepared on 3D carbon paper substrate was 4.2 times higher than that of commercial Pt / C material at the potential of -0.1 V / V vs.RHE.
【学位授予单位】：吉林大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：O643.36;TB383.1

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