Preparation Of Mesoporous Tungsten Carbide/carbon Composites Via Template Method And Its Electrochemical Activitiy

As a kind of high efficient,clean and environmental-friendly new energy,direct methanol fuel cell(DMFC)is still faced with many problems,such as the poisoning of catalyst,the poor durability or short life time.To avoid these problems,one strategy is choosing tungsten carbide(WC)and its composites as the anode materials.Tungsten carbide(WC)has been found possessing a catalytic behavior similar to Pt metal and a promising catalytic activity for methanol oxidation.And it is favored in consideration of its resistance to CO poisoning.However its catalytic activity is much lower than that of platinum because of its low specific surface area and poor electrical conductivity.This study focuses on the preparation of WC-containing composites with high specific surface area.Due to mesoporous materials possess high surface area,excellent mesochannels,high thermal stability and good electrical conductivity,they are applied as carrier in batteries.This paper synthesized tungsten earbide/mesoporous carbon(WC/C)composites by means of a template method,which can modify the electronic structure and increase the electro-catalytic performances of WC.The main achievements can be summarized as follows:Primarily we used phenolic resol acted as the precursor both for carbon support and also the carbon resource of tungsten carbide.Tungsten hexachloride is used as a tungsten precursor along with triblock copolymer Pluronic F127 as pore-forming component.Structural characterizations indieated that the composite had a high surface area,large pore volume and narrow pore size distribution.Using the WC/C as the support,we synthesized Pt-WC/C by microwave heating method to act as an electrocatalyst.It was found that the Pt-WC/C catalyst had a higher methanol oxidation performance and better stability than the commercial Pt/C.Based on these previous experiments,the normal stober method is used to prepare WC/C.Through microwave-assisted heating method instead of hydrothermal reaction,the developed stober method is extended to prepare tungsten carbide/carbon composites.The obtained catalysts have uniform appearance.After loading with platinum nanoparticles,the composites Pt-WC/C have been found showing much higher catalytic activity for methanol oxidation.In addition,we took advantages of microwave assisted heating method to study the effect of carbon precursor and template agent on the composite materials.Sucrose is identified as a kind of ideal carbon precursor.Compared with different templates,the composite material prepared by soft template has the optimal structure and performance.