Controlled synthesis of Ag/Fe2O3 nanocomposites on graphene as electrocatalyst for oxygen reduction reaction in alkaline media

• Main Authors: Wei-quan Chen, 陳威銓
• Other Authors: Chun-hu Chen
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/51469497748667692557

碩士 === 國立中山大學 === 化學系研究所 === 104 === Research on alternative energy conversion and storage of renewable energy technologies is very important. Oxygen reduction reaction (ORR) plays a key role in the fuel cells. Pt/C remains the most efficient ORR catalysts, but the high cost and poor stability limit its wide application in fuel cell technologies. We attempt to explore cheap and effective non-noble metal electrocatalysts as the alternatives to Pt-based catalyst in ORR. Iron oxides have sluggish electron transfer kinetics for oxygen reduction in alkaline media. In our study, we have effectively developed a two-step thermal treatment to synthesize Ag/Fe2O3/N-graphene (Ag/FNG) catalysts. Due to its decomposition at high temperatures, DMF solvent can increase the electrocatalytic performance, nitrogen doping, graphene dispersity. Although DMF solvent ensures great enhancement in ORR performance, the natures of iron oxides still limit an overall 2-electron transfer pathway. Through the addition of a few quantity of silver ion under solvothermal treatment, Ag/FNG-ST have shown the best electrocatalytic activities because of the strong interaction of Ag/Fe2O3.The synergistic effect in Ag/FNG-ST displays the lowest onset potentials, higher electron transfer number(n=~3.9), and efficient mass-transport in kinetic-diffusion control region. We found that DMF solvent will result in better crystallization of iron oxides and bonding with Ag nanoparticles, which changes the electronic structure of iron oxides. This leads to the rise of binding energy to the adsorbed oxygen, which facilitates the O-O bond splitting, and improves the catalytic activities.