Preparation Of Carbon Nanotubes By Microwave Plasma Chemical Vapor Deposition And Supporting Metal Catalyst

With the development of technology, more and more people realize the importantof protecting environment. Development and using of green energy has become a hotresearch topic, and the fuel cells is one of the green energy. The fuel cells is usingredox reaction between cathode and anode to produce chemical energy, and thenmaking chemical energy into electrical energy. The research focus of the fuel cells isabout how to improve catalytic efficiently. For this research focus, this paper usemicrowave plasma chemical vapor deposition (MPCVD) to fabricate carbonfiber/carbon nanotubes electrode, then making electrochemical test for the Pt whichload on the electrode, finally using this electrode to package the fuel cells. Specificcontent includes the following aspects:(1) Growing CNTs on the surface of carbon fiber by using MPCVD, andanalyzing the effect of different factor on the microwave power, reducing time,pre-acidification of the carbon fiber, concentration of nickel nitrate adsorption, theadsorption of nickel nitrate time and so on. Morphological characterization by SEM,and getting the best process preparation CF/CNTs composites: At first step, thecarbon fiber is pretreated in the mixed acid, then the0.20mol/L of nickel nitrateconcentration of adsorbed with36h, finally growing CNTs in the hydrogen flow rateis55sccm, methane flow rate is3.3sccm, growth pressure is4.5KPa, microwavepower500W, reaction time is60min.(2) The Pt nanoparticles are load on CNTs by MPCVD reducing, the researchshows that the Pt nanoparticles have smaller diameter, performance, uniformlydispersion by XRD and TEM. In electrochemical test, the catalyst have goodelectrochemical and strong stability. It is enough to explain the plasma reductionmethod is better than NaBH4reduction method.(3) The fuel cells electrode by using the CF/CNTs/Pt composites, and packagingthe fuel cells. The results show that when the flow rate reaches60ul/min, the currentdensity becomes stable. If we continue to increase the flow rate, it has little influence to the cell density. Because the electrode is cross-dimensional shape, increasing thedistance while the liquid flows through the carbon fiber in fact. So the catalyst hasbeen fully utilized, and improving fuel cell current density and power densityeffectively. The maximum power density of2.2mW/cm2.