Loredana Preda
Institute of Physical Chemistry “IlieMurgulescu†of Romanian Academy, Romania
Title: Electrochemical performance of hybrid electrodes based on graphene and CNW for fuel cells and supercapacitors applications
Biography
Biography: Loredana Preda
Abstract
Fuel cells and supercapacitor applications could much contribute to meeting the tremendous energy demand of modern society, as they represent appropriate alternatives for electricity generation and storage. In the present work, the performances of new WO3-decorated electrodes for supercapacitor applications were assessed. Tungsten oxide was electrochemically deposited on graphite supports (G), functionalized with either reduced graphene oxide (WO3/rGO/G) or carbon nanowalls (WO3/CNW/G). The electrochemical tests demonstrated that the presence of carbon nanowalls significantly enhances the capacitive performances of these new WO3-based electrodes (the capacitance of WO3/CNW/G, appraised from galvanostatic charge-discharge experiments, was ca. 351 mF/cm2 at an applied current density of 1 mA /cm2 ), whereas the presence of graphene leads to a less significant increase of capacitive performance (the capacitance of WO3/rGO/G was ca. 71 mF/cm2 at an applied current density of 1 mA /cm2 ). Based on these observations and on the SEM results (Fig.1), one may assert that the presence of CNW provides mainly better electrical conductivity and enhanced double layer capacitance of the electrode material, mainly due to the morphology adopted by CNW on graphite. Additionally, in view of fuel cells applications, the electrocatalysis activity towards methanol oxidation of these new Pt-decorated electrodes was herein assessed. Platinum nanoparticles were electrochemically deposited on a conductive substrate, functionalized either simply with graphene, (Pt/GR) or with graphene modified with boron-doped diamond powder (Pt/GR-BDDP). The electrochemical tests pointed out that the presence of boron-doped diamond powder (BDDP) into the graphene facilitates the overall methanol oxidation process and provides a better resistance to fouling via CO-poisoning of the electrocatalyst. Additional investigations revealed that the inclusion of BDDP allows a better exposure of the edge planes of the graphene platelets which enables a better accessibility of Pt particles to species from the solution.