Nickel/mesoporous silica (SBA-15) modified electrode: An effective porous material for electrooxidation of methanol

Oxidation of methanol (CH3OH) leads to large overvoltage at most nonmodified electrode surfaces. The development of a novel modified electrode for electrocatalytic oxidation of methanol to decrease overvoltage is of interest. In this paper, we report a new material siliceous (SBA-15)-modified carbon paste electrode based on mesoporous nickel modified SBA-15 for methanol electrooxidation. Mesoporous SBA-15 nanoparticles were synthesized using amorphous silica, which was extracted from sorghum with approximately 80% purity. The synthesized mesoporous SBA-15 nanoparticles were characterized by the XRD, SEM, TEM, TGA and BET. The synthesized SBA-15 nanoparticles are rod-like shapes with average diameter of 82 nm and length in the range of 50-250 nm. Mesoporous silica (SBA-15) can be modified with Ni(II) ions (Ni/SBA) by dispersion in a 0.1 M nickel chloride solution. The modified electrode was prepared by incorporation of nickel (II)-mesoporous silica in carbon paste (Ni/SBACPE). Ni/SBACPE was used to investigate the electrocatalytic oxidation of methanol in alkaline solution by cyclic voltammetry (CV) and chronoamperometry (CA). Cyclic voltammetry of methanol on Ni/SBACPE showed that oxidation current was increased by using nano-sized mesoporous silica compared to the carbon paste electrode (CPE). Also, the rate constant for the catalytic reaction (k) of methanol is obtained. (C) 2012 Elsevier Ltd. All rights reserved.