Delafossite CuFeO₂ photocathodes have recently attracted attention for water splitting due to their suitable band gap (∼1.5 eV) and high stability in aqueous media. The preparation of CuFeO₂ usually requires long and energy‐intense treatments in an inert atmosphere for the full conversion of spinel CuFe₂O₄ to delafossite CuFeO₂. Herein, we report the preparation and characterization of highly uniform and stable CuFeO₂ thin films obtained via a combination of inexpensive ultrasonic spray pyrolysis followed by a short hybrid microwave treatment (∼4 min). The resulting films show good stability in alkaline media and produce a photocurrent of ∼650 μA/cm² under 1.5 AM simulated sunlight and with oxygen bubbling. The effect of the rapid transformation from the spinel to the delafossite phase induced by hybrid microwave annealing was investigated with synchrotron‐based X‐ray absorption spectroscopy (XAS) and X‐ray photoelectron spectroscopy (XPS).

中文翻译：

---

超声波喷雾热解-混合微波退火法简便地两步合成铜铁矿CuFeO2光电阴极

Delafossite CuFeO ₂光电阴极由于其合适的带隙（〜1.5 eV）和在水性介质中的高稳定性而最近引起了水分解的注意。CuFeO的制备₂通常需要长且在惰性气氛中的能量密集的治疗为尖晶石的CuFe的完全转化₂ Ò ₄至铜铁矿CuFeO ₂。本文中，我们报告了通过廉价的超声喷雾热解，然后进行短暂的混合微波处理（约4分钟）的组合获得的高度均匀且稳定的CuFeO ₂薄膜的制备和表征。所得薄膜在碱性介质中显示出良好的稳定性，并产生约650μA/ cm ²的光电流。在1.5 AM的模拟阳光下并带有氧气鼓泡。通过基于同步加速器的X射线吸收光谱（XAS）和X射线光电子能谱（XPS）研究了混合微波退火引起的从尖晶石相到铜铁矿相快速转变的影响。