| Summary: | 碩士 === 國立高雄應用科技大學 === 化學工程與材料工程系 === 99 === A standing Ag nanosheet array was successfully deposited using an electrochemical method. The results demonstrated that the adsorption of polyvinylpyrrolidone (PVP) over the Ag (111) plane during deposition (1) inhibits the crystalline growth in the [111] direction, (2) stacks atomic faults in the fcc structure, and (3) forms a standing Ag nanosheet composed essentially of (111) planes.
The morphologies of silver layer deposited at lower current density(3 mA/cm2) and higher current density(20~30 mA/cm2) were nanosheet structure and branch-like structure, respectively.
In application, this Ag nanosheet array can be successfully used as oxygen reduction (OR) catalyst in 1 M NaOH electrolyte. The mass activity analyzed from thin-film rotating disk electrode (at -0.4 V (Ag/AgCl)) was 2.09 10-3 mA μg-1. The activity was 1.31 times greater than 1.59 10-3 mA μg-1, with 27.9 nm Ag nanoparticles. Based on Koutecky-Levich equation, the involved electron number for OR (at -0.2 V (Ag/AgCl) was 3.97 which is higher than 2.22, the electron number of Ag nanoparticles.
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