tailieunhanh - Báo cáo hóa học: " Optimization, Yield Studies and Morphology of WO3 Nano-Wires Synthesized by Laser Pyrolysis in C2H2 and O2 Ambients— Validation of a New Growth Mechanism"

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: Optimization, Yield Studies and Morphology of WO3 Nano-Wires Synthesized by Laser Pyrolysis in C2H2 and O2 Ambients— Validation of a New Growth Mechanism | Nanoscale Res Lett 2008 3 372-380 DOI s11671-008-9169-6 NANO EXPRESS Optimization Yield Studies and Morphology of WO3 Nano-Wires Synthesized by Laser Pyrolysis in C2H2 and O2 Ambients Validation of a New Growth Mechanism B. W. Mwakikunga A. Forbes E. Sideras-Haddad C. Arendse Received 28 July 2008 Accepted 3 September 2008 Published online 25 September 2008 to the authors 2008 Abstract Laser pyrolysis has been used to synthesize WO3 nanostructures. Spherical nano-particles were obtained when acetylene was used to carry the precursor droplet whereas thin films were obtained at high flow-rates of oxygen carrier gas. In both environments WO3 nanowires appear only after thermal annealing of the as-deposited powders and films. Samples produced under oxygen carrier gas in the laser pyrolysis system gave a higher yield of WO3 nano-wires after annealing than the samples which were run under acetylene carrier gas. Alongside the targeted nano-wires the acetylene-ran samples showed trace amounts of multi-walled carbon nano-tubes such carbon nano-tubes are not seen in the oxygen-processed WO3 nano-wires. The solid-vapoursolid SVS mechanism B. Mwakikunga et al. J. Nanosci. B. W. Mwakikunga C. Arendse CSIR National Centre for Nano-Structured Materials . Box 395 Pretoria 0001 South Africa e-mail bmwakikunga@ B. W. Mwakikunga E. Sideras-Haddad School of Physics University of the Witwatersrand Private Bag 3 . Wits 2050 Johannesburg South Africa B. W. Mwakikunga Department of Physics and Biochemical Sciences University of Malawi The Polytechnic Chichiri Private Bag 303 Blantyre 0003 Malawi A. Forbes CSIR National Laser Centre . Box 395 Pretoria 0001 South Africa e-mail aforbes1@ A. Forbes School of Physics University of Kwazulu-Natal Private Bag X54001 Durban 4000 South Africa Nanotechnol. 2008 was found to be the possible mechanism that explains the manner of growth of the nano-wires. This model based on the theory from basic statistical .