Nano-platinum (nickel)/Multi-walled Carbon Nanotubes/RTILs Composites For Formaldehyde, Carbon Monoxide And Water Sensing

Platinum nanoparticles on polyaniline-coat multi-walled carbon nanotubes were fabricated by electrochemical method at paraffin-impregnated graphite electrode (Pt/PAN/MWCNTs/WGE). The material was characterized by various methods including field emission scanning electron microscope (FE-SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and electrochemical techniques. The electrode had been effectively applied towards formaldehyde (HCHO) sensing. A good linear response curve from 1×10^-9 to 1×10^-3 mol·L^-1 could be obtained with a lower detection limit of 4.6×10^-11 mol·L^-1 (S/N = 3). The successful preparation of nanocomposites opened a new path to fabricate the promising sensor for HCHO.Platinum nanoparticals/muti-walled carbon nanotubes and nikel nanoparticals/ muti-walled carbon nanotubes catalyst were synthesised using ultrasound method respectively. The mixture of catalysts, ionic liquid n-octylpyridinum hexafluorophosphate (OPFP) and conductive hydrogel was used as sensitive membrace for carbon monoxide (CO) sensing (Pt-Ni/MWCNTs/OPFP). The electrode showed an excellent electro-catalysis effect towards the redox of CO, it was successfully used in detection of CO in the concentration of 10 100 ppm with a detection limit of 1 ppm (S/N = 3). Further, the CO sensing prepared was applied to fabricate a portable CO detection device.The electrochemical behaviors of water were studied in detail on nickel electrode using UV-spectrophotometry, cyclic voltammetry and A. C. Impedance in1-butyl-3-methyllimidazolium tetrafluoroborate ([C_4mim][BF₄]). Both [C_4mim][BF₄] and Ni electrode played a cooperative electro-catalysis effect towards the redox of water. Hydrogen peroxide was produced by the direct electrolysis of water in [C_4mim][BF₄]. A good linear relationship was acquired between the water concentration and the oxidative peak current. With the increase of water concentration, the impedance was significantly decreased. The present result showed two promising application in hydrogen peroxide production and water sensing using [C_4mim][BF₄] as electrolyte.