1675
Fabrication of Different Crystalline Diamond Films and Their Application As Anodes for the Oxidation of Human Urine

Wednesday, 1 June 2016: 15:40
Sapphire 410 B (Hilton San Diego Bayfront)

ABSTRACT WITHDRAWN

Diamond shows several extreme outstanding properties, such as high Young's modulus, low surface roughness and chemical inertness et al. Thus, it has been used extensively in many fields including microelectromechanical systems, electron field emitters and electrochemistry. The diamond film will be conductive after boron-doping, and therefore it can be used as a popular candidate anode for the electrochemical oxidation of organic containments in aqueous solution since it shows a wide potential window, low background current, high electrochemical stability and corrosion resistance. Water recycling would be the most realistic and economical way for human being in confined space station where it is cut off from the atmosphere for a long time.

In our work, hot filament chemical vapor deposition (HFCVD) method was employed to fabricate microcrystalline and nanocrystalline diamond films using only hydrogen and methane as precursor. Different factors such as methane concentration, substrate temperature and reaction pressure were studied and it reveals that methane concentration is the major contribution on the morphology change. The resulted morphology of diamond films changed from microcrystalline to nanocrystalline when the methane concentration increased from 2% to 10%. Boron-doped microcrystalline and nanocrystalline diamond films were both used as anodes for the electrochemical degradation of human urine. They show comparable efficiency on the degradation of organic compounds on both electrodes, and while show a small difference on the oxidation of chlorine ions and ammonia ions. However, the nanocrystalline diamond anode shows a longer lifetime due to the lower surface roughness in comparison with the microcrystalline diamond anode. Herein, the nanocrystalline diamond anode is promising for the industrial applications in the electrochemical oxidation of wastewater in the future.