Electrochemically co-deposited silicate sol–gel/PdAu alloy nanostructures and their application in electrocatalytic methanol oxidation

Bimetallic PdAu alloy nanostructures incorporated ethylene diamine functionalized silicate sol-gel (ES) nanocomposite materials on indium-tin-oxide (I) electrodes (I/ES-PdAu) were prepared by facile electrochemical method. X-ray diffraction patterns confirmed the formation of single-phase bimetal PdAu alloy nanostructures at the electrode. X-ray photoelectron spectroscopy analysis confirmed the existence of a zero oxidation state of Pd and Au metals at the I/ES-PdAu electrode. Morphology analysis revealed the formation of anisotropic nanostructures of Au, Pd and PdAu alloy nanostructures with different sizes and shapes at the modified electrodes. Electrocatalytic methanol oxidation reaction (MOR) was studied and enhanced methanol oxidation activity was observed at the bimetallic I/ES-Pd 75 Au 25 and I/ES-Pd 50 Au 50 modified electrodes when compared to pristine I/ES-Pd 100 , I/Pd 100 and I/ES-Au 100 modified electrodes. The I/ES-Pd 75 Au 25 modified electrode was found to be the best electrocatalyst which showed lower overpotential with higher mass activity (0.144 A/mg Pd ) for MOR. Interestingly, when Pd was combined with Au in the presence of ES silicate sol-gel the bimetallic PdAu alloy nanomaterials showed enhanced MOR activity. The MOR current observed at the I/ES-Pd 75 Au 25 electrode was nearly 1.8 times higher than that of the I/Pd 75 Au 25 electrode without ES silicate sol-gel. The stability of the I/ES-Pd 75 Au 25 electrode was tested by scanning 200 continuous cycles and the catalytic current was found to decrease only <5%. Graphical abstract Electrochemically co-deposited PdAu bimetallic materials embedded in N-[3-(trimethoxysilyl) propyl]ethylenediamine silicate (ES) sol-gel modified electrode (I/ES-Pd 75 Au 25 ) displayed 8.7 and 3.2 times higher methanol oxidation current and mass activity when compared to the pristine I/ES-Pd 100 modified electrode due to ES silicate sol-gel supported mass interaction between PdAu alloy nanostructure with the analyte.