Electrostatic Layer-by-Layer Assembled Au Nano particle/MWNT Thin Films: Microstructure, Optical Property, and Electrocatalytic Activity for Methanol Oxidation

Gold nanoparticle/multiwall carbon nanotube (AuNP/MWNT) thin films were fabricated by using the layer-by-layer (LBL) assembly technique. The microstructure of the film was characterized by TEM and AFM, which showed that the MWNTs in the AuNP/MWNT LBL films are randomly entangled to form a dense network, in which the AuNPs are intercalated. The plasmonic properties and electrocatalytic activity of these films were studied as it function of number of bilayers. Surface plasmon resonance of the AuNP/MWNT films increased linearly and exhibited a red shift with increasing number of bilayers as a result of increasing sizes of the AuNP agglomerates in the films. The AuNP/MWNT films were electrochemically active toward methanol oxidation reaction in alkaline solution. Linear sweep voltammograms revealed a systematic increase in the methanol oxidation current with increasing number of bilayers. This work offers promise to the development of efficient electrodes based on metal nanoparticle/MWNT nanoassembly for electrochemical energy conversion devices such as alkaline fuel cells and biosensors.