Conducting-Polymer Nanocomposites as Synergistic Supports That Accelerate Electro-Catalysis: PEDOT/Nano Co3O4/rGO as a Photo Catalyst of Oxygen Production from Water

Mohammed Alsultan,Amar Al-Keisy,Anwer M Ameen,Gerhard F Swiegers

doi:10.3390/jcs5090245

Abstract

This work describes how conducting polymer nanocomposites can be employed as synergistic supports that significantly accelerate the rate of electro-catalysis. The nanocomposite PEDOT/nano-Co3O4/rGO is discussed as an example in this respect, which is specific for photo electro-catalytic oxygen (O2) generation from water using light (PEDOT = poly (3,4-ethylenedioxythiophene); rGO = reduced graphene oxide). We show that the conducting polymer PEDOT and the conductive additive rGO may be used to notably amplify the rate of O2-generation from water by the nano catalyst, Co3O4. A composite film containing the precise molar ratio 7.18 (C; PEDOT):1 (Co):5.18 (C; rGO) exhibited high photocatalytic activity (pH 12) for the oxygen evolution reaction (OER) at 0.80 V (vs. Ag/AgCl), with a current density of 1000 ± 50 μA/cm2 (including a photocurrent of 500 μA/cm2), achieved after >42 h of operation under illumination with a light of intensity 0.25 sun. By comparison, the best industrial catalyst, Pt, yielded a much lower 150 μA/cm2 under the same conditions. Oxygen gas was the sole product of the reaction.

Highlights

Electro-catalysis is a field of increasing importance due to the rapidly declining cost of renewable electricity
Very low-cost electricity of this type may be expected to increase the demand for devices that utilize electro-catalytic electrodes, such as those used in water-splitting solar cells
In the present work we describe the application of this approach to an example system that has not been previously studied or reported, namely the use of the light-absorbing conducting polymer poly (3,4-ethylenedioxythiophene) (PEDOT), combined with the conductive additive reduced graphene oxide, rGO, in the amplification of photo electrocatalytic oxygen production from water by the well-known water oxidizing electro-catalyst nano Co3 O4

Summary

Introduction

Electro-catalysis is a field of increasing importance due to the rapidly declining cost of renewable electricity. The National Renewable Energy Laboratory (NREL) (Golden, Colorado, USA) recently published data showing that the cost of electricity produced by renewable energy was expected to continue its sharp decline over the decade, reaching. Very low-cost electricity of this type may be expected to increase the demand for devices that utilize electro-catalytic electrodes, such as those used in water-splitting solar cells. The water-splitting reaction generating H2 and O2 gases follows the equation: 2H2 O→2H2 + O2 (E0 = 1.23 V). It is important to develop techniques that maximize the performance of nano-particulate electro-catalysts, which are typically deposited as thin films on electrode surfaces. One approach that has recently been developed by our research group in this respect involves the use of conducting polymers [2] and conductive additives as supports that create synergies with the electro-catalyst to maximally accelerate the overall electrocatalytic rate [3,4,5,6,7,8,9,10]

Methods

Results

Conclusion