Tailored IrO2@ZIF-67 nanocomposites for efficient oxygen evolution reaction: Insights into catalyst design and performance enhancement

Abstract

The pursuit of effective electrocatalysts for the oxygen evolution reaction (OER) is crucial for advancing sustainable energy technologies. Efficient OER catalysts play a vital role in the development of water splitting systems, which are fundamental for producing hydrogen—a clean and renewable energy source. The synthesis of IrO2 nanoparticles embedded in ZIF-67 nanostructures has been explored to improve the performance of OER electrocatalysts. The resulting IrO2@ZIF-67 composite catalyst demonstrates a remarkable overpotential of 220 mV and 290 mV at current densities of 10 and 50 mA cm⁻2, alongside a low Tafel slope of 58 mV dec⁻1, significantly outperforming the pristine ZIF-67 catalyst. Integrating IrO2 nanoparticles into the ZIF-67 matrix significantly enhances both the catalytic activity and durability of the material. Extensive electrochemical testing reveals that the IrO2@ZIF-67 catalyst maintains exceptional stability, operating consistently for over 50 h at a current density of 50 mA cm⁻2 without significant degradation. This enhanced performance is attributed to the synergistic effects between the highly active IrO2 nanoparticles and the robust ZIF-67 framework, which collectively facilitate efficient charge transfer and improve structural integrity during prolonged OER operation. These findings highlight the potential of IrO2@ZIF-67 nanostructures as a promising electrocatalyst for sustainable water splitting applications, providing a pathway towards the development of more efficient and durable OER catalysts. © 2024 Hydrogen Energy Publications LLC