Biopreparation of Highly Dispersed Pd Nanoparticles on Bacterial Cell and Their Catalytic Activity for Polymer Electroly
- PDF / 167,152 Bytes
- 7 Pages / 612 x 792 pts (letter) Page_size
- 49 Downloads / 199 Views
1272-PP06-03
Biopreparation of Highly Dispersed Pd Nanoparticles on Bacterial Cell and Their Catalytic Activity for Polymer Electrolyte Fuel Cell Takashi Ogi, Ryuichi Honda, Koshiro Tamaoki, Norizo Saito, Yasuhiro Konishi Chemical engineering, Osaka Prefecture University, Sakai, 599-8531, Japan.
ABSTRACT Rapid development in the area of low-temperature fuel cells has led to increased attention on catalyst synthesis with cost effective and environmentally-benign technology (green chemistry). In this study, a highly dispersed palladium nanoparticle catalyst was successfully prepared on a bacterial cell support by a single-step, room-temperature microbial method without dispersing agents. The metal ion reducing bacterium Shewanella oneidensis were able to reduce palladium ions into insoluble palladium at room temperature when formate was provided as the electron donor. The prepared biomass-supported palladium nanoparticles were characterized for their catalytic activity as anodes in polymer electric membrane fuel cell for power production. The maximum power generation of the biomass-supported palladium catalyst was up to 90% of that of a commercial palladium catalyst.
INTRODUCTION Low-temperature fuel cells generate power by direct electrochemical conversion of fuel (hydrogen/methanol) with oxidant (oxygen/air) to produce water/CO2. In a fuel cell, the anode (fuel electrode) and cathode (oxidant electrode) are installed on either side of a polymer electrolyte membrane. Each electrode is coated on one side with a thin catalyst layer. Hydrogen/methanol is fed into the anode side of the fuel cell and oxygen/air enters through the cathode side. In the case of hydrogen, it is dissociated by the catalyst on the anode and transformed into a proton and an electron. The electrons and protons flow through an external circuit and the polymer electrolyte membrane, respectively. They then react with oxygen to form water at the cathode. The catalyst used in a fuel cell is composed of noble metal nanoparticles and support materials. Supported metal nanoparticle catalysts have been prepared by various methods including microwave irradiation [1-3], chemical vapor deposition [4], impregnation and reduction of metal precursors in a microporous support [5,6], the colloidal method [7,8], and the microemulsion method [9,10]. These methods generally require an elevated temperature to complete the reduction of soluble noble metals and expensive protecting agents such as surfactants to inhibit agglomeration of the nanoparticles and the support material. Any organic stabilizer must then be removed from the catalyst often by heating at a high temperature. Therefore, it is essential to develop a novel nanoparticle catalyst preparation method that uses less toxic precursors (e.g. water as the solvent), fewer reagents and synthetic steps, and a reaction temperature close to room temperature. Microbial methods are attractive for the direct preparation of noble metal nanoparticle catalysts on bacterial cells as they are economical, safe, and envir
Data Loading...
