Novel Bifunctional Electrocatalyst for ORR Activity and Methyl Parathion Detection Based on Reduced Graphene Oxide/Palladium Tetraphenylporphyrin Nanocomposite

We introduce a facile, eco-friendly reduced graphene oxide/palladium tetraphenylporphyrin (RGO/Pd–TPP) nanocomposite for oxygen reduction reaction (ORR) and environmental pollutant detection. The catalytic properties of RGO/Pd–TPP toward ORR and methyl parathion (MP) reduction showed excellent performance due to the synergism between RGO and Pd–TPP. The other properties of RGO/Pd–TPP nanocomposite were characterized by various microscopic and spectroscopic techniques. The as-prepared RGO/Pd–TPP electrocatalyst was further fabricated on electrode to study the ORR activity and MP sensing. The RGO/Pd–TPP modified electrode shows higher current density and less methanol tolerance than the Pt/C electrode, which revealed that the proposed material can be used as an excellent alternative to commercial Pt/C electrode. In addition, the electrocatalytic reduction of MP on RGO/Pd–TPP/GCE was briefly investigated and achieved a good analytical performance with excellent linear range (0.1–125 μM), low detection limit (7.4 nM), and higher sensitivity (4.1084 μA μM^–1 cm^–2). Besides, the modified electrode has successfully applied for the determination of MP insecticide in various water and food samples. Therefore, the finding of RGO/Pd–TPP nanocomposite can be regarded as an effective catalyst to enhance the electrocatalytic activity toward ORR and MP reduction.