预置活性物前驱体脉冲电沉积制备DMFC电极

Preparation of Electrodes for Direct Methanol Fuel Cell by Pulse Electro-Deposition of Pregnant Active Precursors in Porous Carbon Layer

摘要:

预先将活性物前驱体置于碳黑层的Nafion微粒体内，利用脉冲电沉积法，使Pt或Pt合金优先沉积于Nafion与碳黑的接合部，以提高催化剂层贵金属的有效率。实验采用循环伏安法（CV）测定电极电催化活性，用XRD、EDS、TEM技术表征催化剂微观结构及金属微粒的元素组成。结果表明，toff/ton =3:1，wPtRu/wC=40%，Pt、Ru原子比为1:1，金属微粒的比表面积为92 m2·g-1、粒径为3.2 nm，甲醇峰电流密度达到82 mA·cm-2，活性物的有效率达到79.1%。

Abstract:

A new method of directly charging active metal nano-particles was developed so as to be used to improve the efficiency of depositing precious metals in catalytic layer. The precursors of active material were impregnated in porous carbon black layer in advance, and Pt or Pt alloy were firstly deposited on the surfaces of carbon black nearby Nafion particles by the pulse electro-deposition method. The performances of the electrodes were characterized by CV, and the structure and composition of deposited nano-particles by XRD, TEM and EDS. The optimum condition of the preparing process is toff /ton=300:100, wPtRu/wC=40% (mass fraction), nPt:nRu=1:1 (atom ratio). The specific surface is 92 m2/g, particle size 3.2 nm. Methanol peak value of current density reaches 82 mA·cm-2. The efficiency of Pt-M in porous catalytic layers is much higher than that of thin film electrode method, reaching about 79.1%.