NiFe- and CoFe-based (oxy)hydroxides stand out as promising and highly active earth-abundant electrocatalysts for the oxygen evolution reaction (OER) in alkaline media. Fe(OH)₂-Ni(OH)₂ and Fe(OH)₂-Co(OH)₂ electrodes have been prepared through a urea-based chemical bath deposition (CBD) method that enables to control and optimize structure and loading. The effect of the spatial arrangement of the metals in the hydroxide deposits on the electrocatalytic activity in alkaline media has been evaluated. Ultrathin films formed by bilayers resulting from the deposition of submonolayer amounts of Ni or Co hydroxides on previously deposited Fe(OH)₂ layers were found to exhibit the best electrocatalytic behavior. The turnover frequency for O₂ generation increases drastically as the amount of either Ni or Co decreases, reaching maximum values 2.6 and 1.6 times higher than those for FTO/Ni(OH)₂ and FTO/Co(OH)₂ electrodes, respectively. This shows that the presence of underlying Fe(OH)₂ nanoparticles plays a crucial role in enhancing the electrocatalytic properties of Ni or Co sites. The fact that these ultrathin electrodes, formed by extremely small amounts of electrocatalysts, show good stability in alkaline media paves the way for their use as transparent electrodes or co-catalysts for water splitting photoanodes.

基于NiFe和CoFe的（氧）氢氧化物脱颖而出，是在碱性介质中进行氧释放反应（OER）的有前途且高活性的富含地球的电催化剂。Fe（OH）₂ -Ni（OH）₂和Fe（OH）₂ -Co（OH）₂电极已经通过基于尿素的化学浴沉积（CBD）方法制备，该方法能够控制和优化结构和负载。已经评估了氢氧化物沉积物中金属的空间排列对碱性介质中电催化活性的影响。由双层形成的超薄膜，其由亚单层量的Ni或Co氢氧化物在先前沉积的Fe（OH）₂上沉积而成发现层表现出最佳的电催化行为。随着Ni或Co含量的减少，O ₂生成的周转频率急剧增加，分别达到FTO / Ni（OH）₂和FTO / Co（OH）₂电极的最大值的2.6和1.6倍。这表明下面的Fe（OH）₂纳米粒子的存在在增强Ni或Co位的电催化性能中起着至关重要的作用。由极少量的电催化剂形成的这些超薄电极在碱性介质中显示出良好的稳定性，这一事实为它们用作透明电极或水分解光阳极的助催化剂铺平了道路。