The electrochemical redox behavior of lead-ruthenium oxide pyrochlore catalyst (Pb2Ru2-xPbxO7-y, x = 0.25) was systematically studied and possible ruthenium redox species were determined by probing with formaldehyde and glucose oxidation reactions using a PVC/Pb2Ru1.75Pb0.25O7-y composite electrode. Trasatti's surface charge formalism was applied to calculate the different accessible interfacial surface charges. Both the outer/inner and anodic/cathodic charge ratios were found very different to those of pure RuO2 electrode. It is important to note that higher cathodic charges were noticed in all scan rates (v) and pHs for Pb2Ru1.75Pb0.25O7-y. The calculated pH(PZC) of 3.9 from the electrochemical measurements match exactly with that of earlier titrimetric result. The electrocatalytic mediated reactions were demonstrated with Ru3+/4+ assisted oxygen reduction reaction and Ru4+/6+ assisted dopamine oxidation using a Nafion/Pb2Ru1.75Pb0.25O7-y composite electrode. Rotating disk electrode technique was adopted to derive kinetics and mechanism of these two catalytic reactions.