Enhanced Oxygen Evolution Reaction Performance of ZnO Nanorods on Activated Carbon Cloth

Abstract

The employment of an abundant and cost-effective electrocatalyst for water splitting gained significant attention, as there is a need for a substitute for precious metals in the production of affordable H₂ as a promising energy carrier. This study addresses the need for cost-effective, high-activity, and binder-free oxygen evolution reaction (OER) electrocatalysts by investigating ZnO nanorods (ZnO NRs) integrated with electrochemically activated carbon cloth (ECAT@CC). Various characterization techniques, including XRD, XPS, and FE-SEM, confirmed the formation of ZnO NRs on ECAT@CC during conventional hydrothermal synthesis in an aqueous solution containing (CH₃COO)₂Zn·2H₂O and C₆H₁₂N₄ at 95 °C. The electrochemical performance was evaluated using linear sweep voltammetry, chronopotentiometry, and electrochemical impedance spectroscopy in alkaline conditions. The ZnO NRs/ECAT@CC annealed for 3 h at 450 °C exhibited superior OER activity, with an overpotential of 1.58 V vs RHE at a current density of 10 mA/cm², and improved charge transfer resistance of 65.89 Ω·cm², significantly lower than that of pristine and ECAT@CC samples. During the stability test, the robustness of the ZnO NRs/ECAT@CC-3h sample was demonstrated over the prolonged operation. This research highlights ZnO NRs/ECAT@CC-3h as a promising, binder-free, and self-supported OER electrocatalyst, which can contribute to more efficient and sustainable processes in electrochemical water splitting.