Study Of Electrocatalytic Oxidation Of CO At Nano-Au And Multi-wall Carbon Nanotubes Midified Pt Electrode

In the dissertation, nano-Au modified Pt electrode was investigated. The chemically modified electrode, prepared by reaction of cysteine and then nano-Au with a Pt electrode, has excellent catalytic activity toward CO. The purity and carboxylic of MWCNTs (multi-wall carbon nanotubes) was also studied also. MWCNTPME (MWCNTs power micro-electrode ) was fabricated by Intercalating Carboxylic MWCNTs into Pt disk micro-electrode. With 0.5 mol·L-1HClO₄ as supporting electrolyte solution, MWCNTPME exhibited high stability and strong catalytic effect toward the electrochemical oxidation of CO. On determining carbon monoxide by cyclic voltammetry, the overpotential decreased 150-200mV and oxidation current of carbon monoxide increased about 2.1 times on MWCNTPME than on a bare Pt disk micro-electrode. The current response was linearly depended on CO concentration over the range 0.72-52μg·ml^-1 at about +700mV relative to Ag/AgCl reference electrode, and linear equation is y = 0.00624x + 0.2299μA with a correlation coefficient of 0.9957. Detection limit was 0.60μg·ml^-1 and the relative standard deviation was 4.8% (n = 5) .A novel electrochemical sensor had been developed for determination of carbon monoxide. The CO gas sensor was based on MWCNTPME as working electrode, an Ag/AgCl as reference electrode, a Pt wire as counter electrode, and a porous polyethylene film which was in direct contact with the gas-containing atmosphere. The sensor was characterized by a short response time and highly reproducible detection of CO. It can be used in the field of environmental monitoring and control.