Study on synthesis of transition-metal nanoparticle decorated graphene and its application for hydrogen storage

• Main Authors: Ying-yu Chen, 陳盈佑
• Other Authors: Chen-chia Huang
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/13955199839233042842

碩士 === 國立雲林科技大學 === 化學工程與材料工程系碩士班 === 101 === In this study, the graphene nanosheets (GNS) were prepared by thermal reduction of graphite oxide (GO), and then were decorated by adding different concentrations of citric acid chelated transition metal ions, such as nickel or cobalt. The modified GNS was physically mixed with activated mesophase carbon microbeads (aMCMB). The modified GNS and composites were used as hydrogen storage materials. The texture characteristics of GNS were determined by nitrogen adsorption analysis. The surface functional groups were determined by X-ray photoelectron spectrometry and Fourier transform infrared spectrometry. The metal contents were measured by an atomic absorption spectrometer. The morphology and crystal structures of GNS were observed by X-ray diffractometer and transmission electron microscope, field emission scanning electron microscope, ultrahigh resolution analytical electron microscope and Raman spectrometer. Hydrogen storage capacity of prepared GNS and composites was obtained by volumetric method. Experimental results showed that the presence of Ni or Co on graphene enhanced hydrogen capacity of GNS by spillover effect. At room temperature (RT) and 55 atm, the hydrogen capacity (0.16 wt%) on the nickel- decorated graphene (5wt% citric-Ni GNS) demonstrated a 75% enhancement compared to that on the pristine graphene (GNS). The hydrogen uptake for the cobalt-decorated graphene (2wt% citric-Co GNS) was 0.147 wt%, which was a 62% enhancement compared to that of the pristine graphene(GNS). For modified GNS/aMCMB (GM) composites, the increases of hydrogen storage capacities of Ni or Co modified GM over on GM were 8.5% and 6.0%, respectively, which implied the spillover effect is retained. However, the hydrogen storage capacity of nickel and cobalt modified GM composite was less than that of the aMCMB. This is presumed that the aMCMB particles are too large, resulting graphene does not uniformly mixed with aMCMB and causing hydrogen atoms cannot spillover to secondary receptor.