Pulse electrodeposited, morphology controlled organic-inorganic nanohybrids as bifunctional electrocatalysts for urea oxidation

Organic-inorganic nanohybrids with nanoscale architectures and electrocatalytic properties are emerging as a new branch of advanced functional materials. Herein, nanohybrid organic-inorganic nanosheets are grown on carbon paper via a pulse-electrochemical deposition technique. A benzo[2,1,3]selenadiazole-5-carbonyl protected dipeptide BSeFL (BSe = benzoselenadiazole; F = phenylalanine; and L = leucine) cross-linked with Ni 2+ ions (Ni-BSeFL) and nickel hydroxide (Ni(OH) 2 ) in a BSeFL/Ni(OH) 2 electrode exhibits stable electrocatalytic activity toward urea oxidation. The cross-linked nanosheet morphology of nanohybrids was optimized by controlling the reduction potential during pulse electrodeposition. The BSeFL/Ni(OH) 2 (−1.0 V) nanohybrid deposited at −1.0 V provides abundant active sites of Ni 3+ with low charge transfer resistance ( R CT ) and high exchange current density ( J 0 ) at the electrocatalytic interface. The nanohybrids with Ni-BSeFL and Ni(OH) 2 show low overpotential and superior stability for electrocatalytic urea electro-oxidation. The BSeFL/Ni(OH) 2 (−1.0 V) nanohybrid based electrode requires a low potential of 1.30 V ( vs . RHE) to acquire a current density of 10 mA cm −2 for the urea oxidation reaction (UOR) in urea containing alkaline solution which is lower than that for water oxidation in alkaline solution (1.49 V vs . RHE). The organic-inorganic nanohybrid BSeFL/Ni(OH) 2 (−1.0 V) shows durability over 10 h for oxygen evolution and urea electro-oxidation, thereby confirming the BSeFL/Ni(OH) 2 (−1.0 V) nanohybrid-based electrode as an efficient electrocatalyst. Pulse-electrodeposited organic-inorganic nanohybrids (BSeFL/Ni(OH) 2 ), which act as electrocatalysts for the electrochemical oxygen evolution reaction (OER) and urea oxidation reaction (UOR), have been synthesised at different reduction potentials.