Synthesis and Characterization of 3-DOM IrO₂ Electrocatalysts Templated by PMMA for Oxygen Evolution Reaction

Three-dimensional ordered macroporous (3-DOM) IrO₂ material was prepared using PMMA as a template and ammonia as a chelator. These 3-DOM IrO₂ honeycomb arrays showed a large surface area and ordered macropores (155 nm in diameter) cross-linked by secondary mesopores. Internal structures of 3-DOM IrO₂ material were observed microscopically through these secondary pores. According to the X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) spectra, 3-DOM IrO₂ has a rutile crystal structure and is mainly composed of iridium dioxide. In acidic electrolytes, the overpotential of 3-DOM IrO₂ material at 0.5 mV cm^-2 was only 0.22 V. Accelerated durability tests demonstrated excellent durability of 3-DOM IrO₂ as an oxygen evolution reaction (OER) catalyst.