Electrochemical Behavior And Morphology of Nano Catalyst For Fuel Cell: The Effect of Ultrasonic and Microwave Techniques Man Van TRAN, Thuy Thi DOAN, Phuc Ngoc DUONG, My Loan Phung LE, Thi Phuong Thoa NGUYEN University of Science, Vietnam National University – Ho Chi Minh City 227 Nguyen Van Cu, District 5, Ho Chi Minh City, Vietnam In this work, we succeed to prepare the Pt/C and PtRu/C composite electrodes by thermal, sonochemical and microwave methods. The synthesized catalysts are nano uniform particles of 1-6 nm diameters, deposited on pretreated Vulcan carbon 30-50 nm sized aggregates. The pH has important effect on reduction efficiency, the structure and particle-size distribution of synthesized catalyst. The ultrasonification gives smaller and more uniform nano particles than others. The electrochemical measurements of composite electrode in methanol showed that oxidation is irreversible and incompleted, the current density increase with pH and the ultrasonic irradiation gives the best catalytic performance. Introduction Platinum (Pt) is the most effective electro-catalyst for hydrogen oxidation in proton exchange membrane fuel cell (PEMFC). However, because of the high cost of Pt, its nano materials, such as nano particles of Pt and Pt alloy or platinum – free catalysts, have attracted attention of researchers (1, 2). The polyol reduction method of metal nano particles synthesis has advantages over the others due to inexpensive reagents. Moreover, the dispersion of nanoparticles may be achieved simply by pH adjusting without using surfactants (3). The aim of this work is synthesize the carbon supported Pt/C and PtRu/C catalysts by a polyol method activated by microwave and ultrasonic techniques. The structure and morphology of the catalyst were characterized and their electrochemical behavior was evaluated. Experimental For catalyst synthesis all the chemicals (Sigma-Aldrich and Merck) were used as purchased. The reagent solutions were prepared with de-ionized water (DI water - 18.2MΩ). Vulcan XC-72R carbon powder (VC_raw) was purchased from Cabot Corporation (USA) and was pre-treated by soaking in 1M HNO 3 solution at room temperature for 10 h under ultrasonic radiation for removal of surface adsorbates. Then the carbon powder was filtered and washed several times with (DI water, dried at 70 o C and then soaked in 1M NaOH solution for 1h. After being filtered and washed continuously with DI water, the cleaned pre-treated Vulcan XC-72R carbon powder (VC_pre) was dried at 70 o C overnight and at 200 o C for 2h and is ready for use in the catalyst synthesis. The carbon supported platinum (Pt/C) and platinum-ruthenium (PtRu/C) nanocatalysts 10.1149/05002.2001ecst ©The Electrochemical Society ECS Transactions, 50 (2) 2001-2008 (2012) 2001