Electrochemical, surface and electrocatalytic properties of layer-by-layer multilayer assemblies composed of silver nanoparticles and a Ni(II)-crown type polyoxometalate

Multilayer assemblies composed of the crown type polyoxometalate, Ni4[(P8W48O148)(WO2)]28−, and silver nanoparticles, have been immobilised onto glassy carbon electrode surfaces through the layer-by-layer (LBL) technique. The resulting thin films have been characterised by electrochemical and surface based techniques with the multilayers showing electrocatalytic ability towards the reduction of chlorate in solution. The layers exhibited redox activity for both the POM and silver nanoparticle moieties with the layers showing good stability towards redox cycling and thin layer behaviour. The layers were found to be highly conductive due to the presence of the nanoparticles as shown by AC impedance and resulting charge transfer resistance values (Rct) obtained for the layers. A clear and significant catalytic ability of Ni4[(P8W48O148)(WO2)]28/AgNP's assembly towards the chlorate reduction was observed with a measured sensitivity of 32.3mAcm−2/(μM).