Max Planck-Cardiff Centre on the Fundamentals of Heterogeneous Catalysis FUNCAT, Cardiff Catalysis Institute, School of Chemistry, Cardiff University, Main Building, Park Place, Cardiff CF10 3AT, U.K.
International Iberian Nanotechnology Laboratory, Av. Mestre José Veiga, Braga 4715-330, Portugal.
J Am Chem Soc. 2023 Mar 22;145(11):6398-6409. doi: 10.1021/jacs.2c13567. Epub 2023 Mar 9.
The oxygen evolution reaction (OER) is crucial to future energy systems based on water electrolysis. Iridium oxides are promising catalysts due to their resistance to corrosion under acidic and oxidizing conditions. Highly active iridium (oxy)hydroxides prepared using alkali metal bases transform into low activity rutile IrO at elevated temperatures (>350 °C) during catalyst/electrode preparation. Depending on the residual amount of alkali metals, we now show that this transformation can result in rutile IrO or nano-crystalline Li-intercalated IrO. While the transition to rutile results in poor activity, the Li-intercalated IrO has comparative activity and improved stability when compared to the highly active amorphous material despite being treated at 500 °C. This highly active nanocrystalline form of lithium iridate could be more resistant to industrial procedures to produce PEM membranes and provide a route to stabilize the high populations of redox active sites of amorphous iridium (oxy)hydroxides.
氧析出反应（OER）对于基于水电解的未来能源系统至关重要。铱氧化物因其在酸性和氧化条件下的耐腐蚀性而成为有前途的催化剂。使用碱金属基底制备的高活性铱（氧）氢氧化物在催化剂/电极制备过程中会在高温（>350°C）下转化为低活性金红石 IrO。根据残留碱金属的量，我们现在表明，这种转变可能导致金红石 IrO 或纳米晶 Li 插层 IrO。虽然向金红石的转变导致活性降低，但与高度活跃的非晶材料相比，Li 插层 IrO 具有相当的活性和改善的稳定性，尽管它在 500°C 下进行了处理。这种高活性的纳米晶形式的锂化铱可能更能抵抗工业生产质子交换膜的程序，并为稳定非晶态铱（氧）氢氧化物的大量氧化还原活性位提供了一种途径。
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