Electrochemically activated platinum nanoparticles trapped by carbon nanotubes for methanol oxidation reaction

Abstract

In this work, we describe the in situ creation of Pt nanoparticles (NPs) through electrochemical activation by potential cycling method on the poly crystalline Pt electrode surface without the use of any binders or reducing agents. Further it has been shown that the Pt NPs formed by electrochemical activation could be entrapped by carbon nanotubes drop casted on the poly crystalline Pt electrode surface. The drop casted CNTs entrap the Pt NPs and make them dissolution resistant so that the Pt NPs would not leach from the surface. Thus prepared electrocatalyst displayed high electroactive surface area and better electrocatalytic activity towards methanol oxidation reaction in acid medium. CNTs supported Pt NPs on the poly crystalline Pt surface were microscopically characterized by FESEM, TEM, HRTEM, and physically characterized by XRD to confirm the presence of Pt NPs. The electrochemical activation, entrapment of Pt NPs on CNTs, measurement of electro active surface area, methanol oxidation and catalytic stability were examined by electrochemical studies. The morphology of the material was well maintained which could be ascribed to the effect of CNTs. Surface decorated CNTs by nanostructured Pt on poly crystalline Pt acting as the catalyst does not show any obvious current decay during the testing period. The catalyst exhibited a very good performance with a lower onset potential for methanol oxidation and the mass activity is found to be 25 A g−1 of Pt. The electrochemically active surface area is found to be high and is calculated to be 28.47m2g−1.