Catalytic and Energy Storage Applications of Metal/Polyaniline Nanocomposites: A Critical Review

Conducting polymers (CPs) have attracted interest as solid supports for metal nanoparticles (MNPs) to improve their stability. In particular, polyaniline (PANI) has gained popularity due to its low cost, high electrical conductivity, stability and ease of preparation. PANI has been combined with various MNPs including silver nanoparticles (AgNPs), gold nanoparticles (AuNPs), platinum nanoparticles (PtNPs) and palladium nanoparticles (PdNPs) which have been used in various applications such as energy storage, catalysis and sensors. This review highlights the various applications of metal/PANI nanocomposites in catalysis and energy storage. The catalytic applications of metal/PANI nanocomposites in oxidation and reduction of pollutants such as toxic fuels and organic dyes to less harmful products have been discussed. Their application on coupling reactions such as C-C coupling, C-N coupling, and Ullman and click chemistry reactions have also been explored. Moreover, the electrocatalytic oxidation of alcohols and alkenes to their respective ketones and epoxides, respectively, by metal/PANI nanocomposites has been explored as well as their possible application in fuel cells. The review further discusses the application of metal/PANI nanocomposites as electrodes for supercapacitors and as bistable memory devices.