pH-universal
electrocatalysts are desirable for high efficiency
of water electrolysis. Herein, we report the facile synthesis of single-phase
perovskite SrIrO3 nanofibers (NFs) and demonstrate that
SrIrO3 NFs are promising electrocatalysts for the oxygen
evolution reaction (OER) in a wide range of pH. Single-phase SrIrO3 NFs were synthesized by electrospinning and subsequent calcination
processes, and the electrocatalytic performance of SrIrO3 NFs toward the OER was evaluated under acidic, neutral, and alkaline
media. A large surface area due to the NF morphology with an average
diameter of 105.5 (± 15.5) nm led to enhanced catalytic activity
of SrIrO3 NFs, representing smaller overpotentials and
Tafel slopes under pH-universal conditions than IrO2/Ir
NFs and commercial Ir/C. SrIrO3 NFs also manifested remarkably
stable activity for continuous OER operation in all three electrolytes,
even though a considerable amount of Sr was leached out of them. The
long-lasting high OER activity of SrIrO3 NFs could be ascribed
to stable Ir cations taking B sites of the perovskite oxide structure,
known as an active site for electrocatalysis. The initial perovskite
crystal structure of SrIrO3 was maintained for a certain
time even after significant Sr leaching. This work is the first application
of SrIrO3 perovskite for pH-universal OER catalysis.
Chromium-iridium oxide (CrxIr1-xO2) alloys with the tube-in-tube morphology were primally prepared as highly efficient electrocatalysts for oxygen evolution reaction (OER) via a simple electrospinning method. The synthetic process with an...
An IrO 2 −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 IrO 2 −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 IrO 2 and 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.
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