LAUSR

Amplifying catalysis by thoughtful exploitation of synergistic effects with interacting supports is a new field of potentially great significance. It is particularly relevant for solar‐assisted reactions that are currently too poorly catalyzed to be practically viable, such as photoelectrochemical splitting of water to produce hydrogen and oxygen. In this work we describe synergistic amplification of water oxidation photoelectrocatalysis by the use of a thin layer electroactive polymer support. Coating of a bare Pt surface with a 0.98 μm thick film of poly(3,4‐ethylene‐dioxythiophene) (PEDOT) containing a specific molar ratio of nano‐Co3O4 (a water oxidation catalyst) and multi‐wall carbon nanotubes (oxidatively stable conductors) synergistically amplifies its rate of water oxidation catalysis by 15‐fold (under the most oxidizing conditions that can be applied to PEDOT without degradation; with light illumination of 0.25 sun). To the best of our knowledge, this film is the most active water oxidation catalyst yet reported under near‐neutral (pH 12) conditions as a proportion of the activity of Pt, which is the industry‐standard catalyst of the reaction.