Surface attached-poly(acrylic acid) network as nanoreactor to in-situ synthesize palladium nanoparticles for H2O2 sensing

A novel amperometric sensor for hydrogen peroxide (H2O2) was developed based on palladium nanoparticles (NPs) in-situ formed on the electrode surface. Poly(acrylic acid) (PAA) was first electrodeposited onto a gold electrode. Then Pd2+ were chemically adsorbed within the PAA network, and subsequently reduced by hydrazine hydrate to form palladium NPs. The size and density of palladium NPs can be easily controlled through controlling the amount of metal ions in the film. The PAA-templated Pd NPs displayed excellent electrocatalytical response to the reduction of H2O2. Under optimal conditions, linear relationship was observed for H2O2 reduction in the concentration range from 10 μM to 25 mM at the applied potential of −0.1 V and the detection limit was 5 μM. The resulted sensor shows fast response and good stability. By varying the metal catalyst and by conjugating biomolecules with the free carboxyl groups of PAA, a variety of new chemical and biosensors could be constructed.