Microwave-assisted Synthesis of Pt-Ni/Graphene Electrode Materials for Direct Methanol Fuel Cell

• Main Authors: WU, YU-YI, 巫毓翊
• Other Authors: SHIH, KUN-YAUH
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/76563676833872105976

碩士 === 國立屏東大學 === 應用化學系碩士班 === 104 === Pt is the most widely used anode catalyst in direct methanol fuel cells (DMFCs). However, Pt catalyst have some disadvantages, such as high cost of metal and poisoning of CO. Therefore, Pt with another metal in a bimetallic catalyst is used to solve these problems. The composites of bimetallic catalyst significantly reduce the Pt demand and overcome the poison effects of CO. The main purpose of this research was to investigate microwave-assisted synthesis of Pt-Ni/Graphene electrode materials for direct methanol fuel cell. The experiment performed to achieve this purpose was divided into four parts：In the first part, Pt-Ni catalyst was synthesized by the microwave-assisted method and X-ray diffraction was used to determine the crystal structure of the catalyst. The component of Pt-Ni alloy catalyst supporting on graphene were discussed. The measurements of H2SO4 (aq.) solution by cyclic voltammetry (CV) was used to determine the minimum amount of catalyst requirement. The results showed that the electrochemical active surface area was 253.05 m2 / g at the Pt3Ni1. In the second part, the microwave power with 500W, 600W, 700W and 800W were investigated for the Pt-Ni alloy catalyst. As the amount of microwave power increases, the heating rate would be faster. Therefore, we observed the comparison of heating rate whether it affects catalyst morphology and particle size. The full width at half maximum of Pt (111) were followed the Scherrer formula in order to calculate Pt-Ni nanoparticle particle size, it showed that the smallest particle size was 2.24 nm with microwave power 700W. In the third part, we discussed the optimal synthesis time for Pt3Ni1/RGO in 700W. The decreased of synthesis time also reduced the consumption of energy and increased the efficiency of methanol. There was the optimal electrochemical active surface area 253.05 m2/g at 100s, and the methanol oxidation reaction had the optimal current density 6.33 mA/cm2. In the fourth part, the influence of different kinds of carrier in Pt-Ni alloy catalyst were discussed. RGO and CNT were used as carriers with Pt3Ni1 at 700W 100s. The result showed that the particle size of Pt3Ni1/RGO was smaller than that of Pt3Ni1/CNT. The electrochemical active surface area of Pt3Ni1/RGO was 5.2 times better than the Pt3Ni1/CNT. Ultimately, we compared Pt/RGO catalyst with Pt3Ni1/RGO catalyst. The results showed that the particle sizes of Pt3Ni1 / RGO catalyst and Pt/RGO catalyst were 2.24 nm and 3.79 nm, respectively. The particle size of the bimetallic catalyst was smaller than Pt/RGO. The electrochemical active surface area of Pt3Ni1/RGO was 1.9 times better than the Pt/RGO.