醇类电催化氧化催化剂的研究进展

醇类电催化氧化催化剂的研究进展

摘要:直接醇类燃料电池（DAFC）是以小分子醇类为燃料、直接将化学能转化为电能的装置。它具有能量转化效率高、燃料来源丰富、储运方便、成本低廉等优点，是理想的便携式电源。为提高碱性介质中多壁碳纳米管（MWCNT）负载 Pd 基催化剂对醇类电氧化反应的催化活性及抗中毒能力，本文采用乙二醇还原法制备了Pd/MWCNT 催化剂，并引入过渡金属进行改性，制备了 PdM/MWCNT（M = Ni、Mo、Ce）二元催化剂。采用透射电子显微镜（TEM）、X-射线光电谱（XPS）及差热分析（DTA）等手段对催化剂的形貌、组成及结构进行表征。以循环伏安法（CV）、线性扫描伏安法（LSV）、电化学阻抗谱（EIS）及计时电流法（CA）等电化学方法考察了催化剂在醇类电氧化反应中的催化活性及抗中毒能力。主要研究结果如下：

（1）采用乙二醇还原法制备了 Pd/MWCNT 催化剂与 PdNi/MWCNT 催化剂，结果表明添加 Ni 后的催化剂在载体表面分散更均匀，平均粒径为 2.34nm。PdNi/MWCNT 催化剂中 Ni 主要以 Ni(OH)2和 NiOOH 形式存在，在碱性溶液中对甲醇的电催化氧化表现出较高的活性。

（2）通过 PdM/MWCNT（M=Mo、Ce）催化剂的优化实验，发现 Mo、Ce 纳米粒子的添加有助于提高催化剂的催化能力，且当 Pd:Mo=1:0.2、Pd:Ce=1:0.1 时，350℃焙烧制得的 PdMo/MWCNT、PdCe/MWCNT 催化剂分别对甲醇、乙醇的电催化氧化活性较为突出，抗 CO 中毒能力较强。

（3）通过对助催化剂钼、铈化合物的焙烧，发现随着温度的升高，金属氧化物的生成量增多，能为催化剂提供较丰富的含氧物种，促进中间产物的继续氧化，从而提高催化剂的抗中毒能力；但焙烧温度过高，会引起催化剂的导电能力下降，甚至破坏碳纳米管载体的结构，使催化剂失效。

Abstrac t: the direct alcohol fuel cell (DAFC) is a device which can convert chemical energy into electrical energy by the small molecule alcohol as fuel.. It has the advantages of high energy conversion efficiency, rich fuel source, convenient transportation, low cost, etc., is the ideal portable power source. In order to improve the alkaline medium multi

walled carbon nanotubes (MWCNTs) load Pd based catalyst for alcohol electro oxidation reaction catalytic activity and anti poisoning ability. This paper using ethylene glycol reduction method for preparing the Pd/MWCNT catalyst, and the introduction of transition metal modified PdM/MWCNT (M = Ni, Mo, CE) binary catalyst was prepared. The morphology, structure and structure of the catalysts were characterized by transmission electron microscopy (TEM), X- ray photoelectron (XPS) and differential thermal analysis (DTA).. By cyclic voltammetry (CV) and linear sweep voltammetry (LSV), electrochemical impedance spectrum (EIS) and timing current method (CA) and electrochemical methods to study the catalytic activity of the catalysts in the methanol electro oxidation reaction and anti poisoning ability. The main results are as follows:

(1) using ethylene glycol reduction method to prepare Pd/MWCNT catalyst and

PdNi/MWCNT catalyst. The results show that after adding Ni catalyst on the surface of the carrier dispersed more evenly, the average particle size of 2.34nm. The PdNi/MWCNT catalyst of Ni mainly exists in the presence of Ni (OH) 2 and NiOOH, and shows higher activity of Electrocatalytic Oxidation for methanol in alkaline solution..

(2) by PdM/MWCNT (M = Mo, CE) catalyst optimization experiment. It was found that the Mo, CE nanoparticles add help to improve the catalytic activity of the catalyst and when Pd:Mo=1:0.2 Pd:Ce=1:0.1, 350 DEG C roasting PdMo/MWCNT, PdCe/MWCNT catalyst respectively electrocatalytic activity for methanol, ethanol is more prominent, the resistance to CO poisoning ability.

(3) by roasting of molybdenum catalyst, cerium compounds, discovered in the production of metal oxide increased with the increase of temperature, catalyst provides abundant oxygenated species, promote intermediates to oxidation, so as to improve the catalyst anti poisoning ability; but calcination temperature is too high will cause catalyst conductivity decreased, and destruction of the structure of carbon nanotube carrier, the catalyst failure.

关键词：直接醇类燃料电池；阳极催化剂；活性；抗中毒；钯、电、核能

Keywords: direct alcohol fuel cell; anodic catalyst; activity; poisoning; PD, electric, nuclear energy.

1.2 燃料电池的概述