Electrocatalytic Activity Enhancement of Multifunctional Co₃O₄ Nanorods for Glucose Sensing and Oxygen Evolution Reaction

To explore a methodology for tailoring the d-band center of metal oxide catalysts, a distinctive composite is synthesized by incorporating polyaniline (PANI) particles with specific atoms of Co 3 O 4 nanorods. The introduction of the requisite amount of PANI significantly enhances the electrocatalytic activity, yielding an excellent functionality with a minimum detection limit of 0.676 μM and a high sensitivity of 3.024 μA μM –1 cm –2 for glucose. The opening potential for the oxygen evolution reaction registers at 1.41 V, while the overpotential is 290 mV. However, when the PANI layer completely covers the Co 3 O 4 surface, a substantial decline in electrochemical properties is observed, indicating that active atoms on the Co 3 O 4 plane should be preferentially exposed. Additionally, density functional theory calculations reveal that bonding of an appropriate quantity of polyaniline particles can modify bonding states and antibonding states of Co–O within the Co 3 O 4 complex, leading to a shift of the d-band center closer to the Fermi level, thereby enhancing its electrocatalytic activity. These findings underscore the practicality of this manipulation strategy for glucose sensing and oxygen evolution reaction.