Layer-by-layer integration of conducting polymers and metal organic frameworks onto electrode surfaces: Enhancement of the oxygen reduction reaction through electrocatalytic nanoarchitectonics

Abstract

In this work we explore a nanoarchitectonics approach to construct functional composite nanomaterials with enhanced electrocatalytic properties. Functional electrodes were designed in order to combine two key elements: high surface area and porosity with electroactivity, thus enabling their application to the enhancement of the electrochemical oxygen reduction reaction (ORR). We propose a simple, yet unexplored, layer-by-layer (LbL) method which makes use of sequential assembly of colloidal suspensions of polyaniline/polystyrene sulfonate (Pani-PSS), and polyallylamine hydrochloride-coated ZIF-8 metal organic framework nanocrystals (PAH-ZIF-8). The Pani-PSS/PAH-ZIF-8 nanoarchitecture thus obtained benefits from the synergy between the electroactivity provided by the negatively charged conducting polymer component (Pani-PSS), and the high-surface area porous environment provided by the positively charged MOF counterpart (PAH-ZIF-8). LbL-assembled films were found to be electrically connected and feature promising increases in the electrocatalytic currents obtained for the ORR in neutral pH aqueous environments.