Electrochemical synthesis of palladium (Pd) nanorods: An efficient electrocatalyst for methanol and hydrazine electro-oxidation

Synthesis of palladium (Pd) nanostructures with unique shapes is crucial due to their shape dependent electrochemical activity. In the current investigation, we demonstrate the electrochemical synthesis of rod-like Pd nanostructures with the assistance of nicotinamide adenine dinucleotide (NAD⁺). As-synthesized Pd nanorods were used as electrocatalysts for electrochemical oxidation of methanol and the development of highly sensitive platform for hydrazine detection. Additive NAD⁺ played an important role in the morphology tuning of Pd nanostructures. Results of morphological study demonstrated the growth of Pd nanorods with an average size of 150 nm. The as-synthesized Pd nanorods had excellent electrocatalytic activity toward oxidation of methanol in alkaline pH and hydrazine oxidation in neutral pH. These Pd nanorods catalyzed the electrooxidation of methanol at −0.17 V with much better tolerance, excellent stability, and oxidation of hydrazine at −0.075 V. The Pd nanorod-based sensing platform delivered a low detection limit of 5 nM, sensitivity of 0.78 ± 0.02 μA mM⁻¹cm⁻², and stable response toward hydrazine sensing without any interference from potential interferents such as Na⁺, K⁺, NO₂⁻, BrO₃⁻, or Pb²⁺ ion. Their electrochemical performances were found to be highly dependent on the morphology of Pd nanostructures.