| Summary: | 碩士 === 國立臺北科技大學 === 有機高分子研究所 === 104 === Graphene is the thinnest and hardest two-dimensional material worldwide; hence, graphene is considered as one of the most promising materials for next generation nanotechnology. By taking the advantage of its unique two-dimensional structure, excellent physical and chemical properties, such as high specific surface area, electrical conductivity, and chemical stability, is observed, so many studies have committed to developing a new method for the preparation of graphene in recent decades, in order to explore the physical and chemical nature and its possible application. Due to the high specific surface area, conductivity and chemical stability of graphene materials, graphene is considered as desirable catalyst supports. Previous studies have already confirmed that graphene can be served as an excellent catalyst support. In contrast, platinum is one of the best electrocatalyst, and widely used as electrode materials for fuel cells. From the literatures, the catalytic activity of platinum catalysts has known to be affected by its composition and catalyst carrier; for example, platinum nanoparticles deposited on graphene can not only increase the conductivity of the environment of platinum but also enhance the activity of that.
Epitaxial graphene nanowalls(EGNWs) with different compression stress were prepared by changing the flow rate of hydrogen. Through structure analysis techniques, we found that epitaxial graphene nanowalls show different stress, but there is no obvious difference in its crystallinity and surface morphology. In order to discuss the effect of different stress on the catalytic activity of the catalyst, high vacuum ion beam sputtering was used to deposit platinum nanoparticles on epitaxial graphene nanowalls on EGNWs with different stress. The hydrogen evolution reaction(HER) was served as a modeling reaction to characterize the catalytic activity of platinum on EGNWs with different stress. The results shows that with increasing compressive stress of EGNWs supports, the Tofel slope of HER on Pt will change from 30 to 40 mV/dec, which reveals that the mechanism of hydrogen evolution change from Volmer-Tafel mechanism to Volmer-Heyrovsky mechanism; besides, η10 also increase from 52 to 73 mV. In this study, we demonstrate the catalytic activity of Pt on different strained graphene. It is worth to note that we illustrate how strain affects the catalytic properties, for the first time, in a systematic experiment instead of simulations.
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