tailieunhanh - Báo cáo hóa học: " Growth of carbon nanowalls at atmospheric pressure for one-step gas sensor fabrication"

Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Growth of carbon nanowalls at atmospheric pressure for one-step gas sensor fabrication | Yu et al. Nanoscale Research Letters 2011 6 202 http content 6 1 202 o Nanoscale Research Letters a SpringerOpen Journal NANO EXPRESS Open Access Growth of carbon nanowalls at atmospheric pressure for one-step gas sensor fabrication Kehan Yu1 Zheng Bo1 Ganhua Lu1 Shun Mao1 Shumao Cui1 Yanwu Zhu2 Xinqi Chen3 Rodney S Ruoff2 Junhong Chen1 Abstract Carbon nanowalls CNWs two-dimensional graphitic platelets that are typically oriented vertically on a substrate can exhibit similar properties as graphene. Growth of CNWs reported to date was exclusively carried out at a low pressure. Here we report on the synthesis of CNWs at atmosphere pressure using direct current plasma-enhanced chemical vapor deposition by taking advantage of the high electric field generated in a pin-plate dc glow discharge. CNWs were grown on silicon stainless steel and copper substrates without deliberate introduction of catalysts. The as-grown CNW material was mainly mono- and few-layer graphene having patches of O-containing functional groups. However Raman and X-ray photoelectron spectroscopies confirmed that most of the oxygen groups could be removed by thermal annealing. A gas-sensing device based on such CNWs was fabricated on metal electrodes through direct growth. The sensor responded to relatively low concentrations of NO2 g and NH3 g thus suggesting high-quality CNWs that are useful for room temperature gas sensors. PACS Graphene Chemical vapor deposition Gas sensors Atmospheric pressure Introduction Graphene possesses many extraordinary properties and has been the subject of intense scientific interest 1-12 . Exceptional values have been reported of ballistic electron mobility 200 000 cm2 V-s for particular samples 13 14 high thermal conductivity 5 000 W m-K 15 Young s modulus approximately 1 100 GPa fracture strength 125 GPa 16 and a high specific surface area approximately 2 600 m2 g relevant to electrical energy storage 5 . .