Development of enzymeless hydrogen peroxide sensors

In the scope of this thesis, the catalysts prepared for the H2O2 determination, dendrimers synthesized by NaBH4 reduction method were all prepared by reduction and dendrimer templated NaBH4 reduction method and the effect of sensor activity and sensitivity were analyzed. Then, Carbon Nanotube (CNT) supported PdxAuy bimetallic catalysts with different stoichiometric ratios were synthesized as a new dendrimer template by NaBH4 reduction method and their activities were investigated for H2O2 reduction reaction. The structural characterization of prepared catalysts was carried out by XRD and SEM analyzes. In addition, electrochemical characterization of these catalysts was carried out by cyclic voltammetry and chronoamperometry methods. Electrochemical sensitivities of CNT supported PdxAuy bimetallic nanocatalysts for H2O2 were examined in 0.1 M pH 7.4 phosphate buffer solution. Since PdxAuy bimetallic nanocatalysts have high electrocatalytic activity, they own a large potential of application in electrochemical processes. The sensitivity for the 10% Pd0.7Au0.3/CNT dendrimer with the highest catalytic activity was found to be 314.25 µA cm-2 mM-1 and the detection limit was 0.2 µM. For Pd/CNTNaBH4 and 10% Pd/CNTdendrimer monometallic catalyst, the sensitivity was found to be 220.32 µA cm-2 and the detection limit was 0.5 µM-1. In addition, when interference effects were examined 10% Pd0.7Au0.3/CNTdendrimer catalyst did not cause any interference in H2O2 determination.