DEVELOPMENT OF COMPOSITE ELECTRODES CONTAINING GEOPOLYMER BINDER FOR ELECTROCHEMICAL APPLICATIONS

Abstract

The requirements for electrode materials are high electronic conductivity, fast kinetics, high mechanical stability, and high chemical stability under oxidative and reductive environment. In this work, composite electrodes have been prepared containing geopolymer (made from Fly Ash (FA)), zinc, and Multiwalled Carbon Nanotubes (MWCNT) or graphite deposited on a nickel foam with different compositions (FA:Zn:MWCNT or FA:Zn:Graphite, mass ratio = 12:6:1 or 6:6:1). While the commercial zinc plate demonstrated clear oxidation and reduction reactions during cyclic voltammetry, no electrochemical reactions of zinc were observed with the composite electrodes. The composite electrodes suffered from high resistance, which could not be overcome even with reduced geopolymer content. The FE-SEM images indicated that the composite electrodes containing MWCNT were better dispersed than those containing graphite. Moreover, the composite electrode containing FA:Zn:MWCNT = 6:6:1 showed a lower overpotential for Oxygen Evolution Reaction (OER) compared to those with FA:Zn:Graphite at the same mass ratio. The surface morphology, homogeneity and chemical compositions lead to the change of the electrocatalyst activity towards OER. The electrode containing MWCNT may be attractive as anode for alkaline water electrolysis for hydrogen production. Further experiments should focus on optimization of the electrode composition to enhance its conductivity, activity and stability.

Keywords

• Cyclic voltammetry
• Geopolymer binder
• Oxygen evolution reaction
• Zinc electrode