Amplified, Synergistic (Photo) Catalytic Water-Splitting by Thin- Film Conducting Polymer Composites

There is currently great interest in harnessing sunlight to generate hydrogen from water. Hydrogen may serve as a future energy carrier that could one day supplant fossil fuels like gasoline or diesel. One of the major challenges with implementing this concept is that, present-day photoelectrochemical (PEC) water splitting systems are either inefficient in their capacity to catalytically split water and/or subject to photocorrosion. The problem typically lies at the interface at which the water-splitting catalytic reaction occurs. One potential solution is to develop a thin-film, catalytic, interfacial layer that may lie between the photo-activated species (e.g. the semiconductor) and the aqueous, liquid phase. Such an interfacial layer could be designed to catalyse water-splitting at a more accelerated rate than is possible in its absence, whilst simultaneously suppressing photocorrosion. Ideally, such a thin-film interface would provide the greatest possible catalytic effect, preferably by synergistic amplification of the catalysis beyond what may be achieved by the catalyst species themselves. This work aimed to study and develop thin-film composites, based on well-known conducting polymer supports, that may serve as such an interfacial layer and that display synergistically amplified water-splitting catalysis. Despite their potential for facilitating high activity, thin-film conducting polymer supports have, historically, expedited only relatively weak performances in, for example, catalytic water oxidation (with current densities in the μA/cm2 range).