An IrO2-ZnO composite nanorod array with distinct morphological features was successfully fabricated through a facile method via a simple acid-base reaction, followed by a postcalcination process. A modulation in the annealing treatment time (t) generated the variation in morphology, at a constant temperature (600 °C), and the nanorod-like growth on the surfaces was revealed at t ≥ 3 h. Especially, the IrO2-ZnO composite nanorod array exhibited superior OER catalytic activities (e.g., a potential of 1.481 V at 10 mA cm-2(vs RHE) and a Tafel slope of 42.9 mV dec-1). Moreover, there was no apparent potential shift with robust long-term cycling stability under acidic conditions, which were much better than those of IrO2and commercial iridium (cIr) and comparable with those of the previously reported outstanding Ir-based OER catalysts. Considering that the nanorod array was fabricated with the loading of the Zn metal component, which showed generally low catalytic activity and poor durability, this study suggests a promising strategy with an extended synthetic methodology for preparing Zn-mixed metal oxides as highly efficient electrocatalysts.
Bibliographical noteFunding Information:
This work was financially supported by the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT or by the Ministry of Education (NRF-2019R1F1A1059969, NRF-2020R1A2B5B01001984, NRF-2018R1A6A1A03025340, NRF-2021R1F1A1053270, and NRF-2019R1F1A1062799).
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- iridium oxide (IrO)
- nanorod array
- oxygen evolution reaction
- zinc oxide (ZnO)