Electrocatalytic oxidation of formaldehyde on novel composite of nickel/ triton-x100/poly(o-aminophenol-co-aniline) modified carbon paste electrode

In recent years, many reports have been published on the oxidation of formaldehyde under a wide range of conditions and on various electrodes [1-4]. Although Pt is one of the most efficientmetal catalysts for oxidation of formaldehyde, it is easily poisoned by the CO-like intermediate produced from incomplete oxidation of the fuel. Another problem intrinsic to Pt is its high cost. One approach to solving these problems is the development of a cheaper, non poison able catalyst while maintaining high activity for the oxidation process. In this approach several reports have already been published on the surfaces of catalysts such as Cu [2], Ni [3], and Ag [4]. It is well known that conducting polymers (CPs) with porous structures and high surface areashave been proved to be suitable host materials for dispersion of metallic particles [5-6]. In the family of conductive polymers, aniline is a molecule used to modify electrode surfaces, forming the polyaniline polymer (PANI). The electropolymerization of aniline by continuous potentialscanning allows the study of the redox properties of the electrogenerated films and their growth. Additionally, in recent years a wide variety of copolymers have been studied for many differentapplications. Copolymerization can be used as a technique to improve the properties of a material. The characteristics of electrochemical copolymerization are highly dependent on the synthesis conditions, in particular, the mole fraction of each of the monomers involved in thereaction [7-9]. This paper deals with electrochemical oxidation of formaldehyde in alkaline solution with a newelectrocatalytic system composed of Ni(II)/Ni(III) redox ions incorporated in poly(oaminophenol- co-aniline)/Triton-X100 film modified carbon paste electrode. At first, copolymericfilm on the surface of carbon paste electrode was formed by successive potential cycling in solution containing o-aminophenol and aniline as monomer and Triton X-100 as a surfactant. Ni(II) ions were incorporated into the electrode by immersion of the copolymeric modifiedelectrode having amine groups in 0.1 M Ni(II) ion solution. The influences of some parameters such as mol ratio of monomers in copolymer formation, thenumber of potential cycling for copolymer formation, and formaldehyde concentration on its oxidation current have been investigated. The rate constant (k) for the chemical reaction between the formaldehyde and nickel hydroxide has been evaluated by chronoamperometry method

کلیدواژه ها:

Electropolymerization ، Copolymer ، Triton-X100 ، Electrocatalytic Oxidation ، Nickel ، Formaldehyde