Assembling a hierarchical well-defined Prussian blue analogues (PBA) construction is a useful way to take earth-abundant elements into application toward hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Herein, we report a unique strategy for in-situ grafting three-dimensional (3D) MnFe-PBA cubes on the top of two-dimensional (2D) MnO₂ nanosheet arrays (PBA@MnO₂) via a facile two-step hydrothermal method with the participation of Ni foam (NF). After experiencing low-temperature pyrolysis in NH₃/Ar atmosphere, the above catalysts are transformed into metal-nitride derivatives (N-FeMnNi). Remarkably, when operated in 1.0 M KOH aqueous solution, the as-obtained PBA@MnO₂-150/30 (where 150 and 30 represent the hydrothermal temperature (°C) and the concentration of K₃Fe(CN)₆ (mM) for preparation, respectively) shows the most outstanding OER activity, with an overpotential of 238 mV at 10 mA cm⁻². Moreover, N-FeMnNi-130/10 requires an overpotential of 101 mV to reach 10 mA cm⁻² for HER. As a result, the two samples are organized to establish a two-electrode cell, with a voltage of only 1.60 V needed to reach 10 mA cm⁻². Meanwhile, it can stably work for 30 h without obvious current attenuation. This work provides a brand new perspective for the design of PBA electrocatalysts towards high-efficiency overall water splitting.

组装层次分明的普鲁士蓝类似物（PBA）结构是一种将富含地球的元素应用于产氢反应（HER）和产氧反应（OER）的有用方法。在这里，我们报告了一种独特的策略，通过一种简便的两步水热方法在二维（2D）MnO ₂纳米片阵列（PBA @ MnO ₂）的顶部上原位接枝三维（3D）MnFe-PBA立方体在镍泡沫（NF）的参与下。在NH ₃ / Ar气氛中经历低温热解后，上述催化剂转化为金属氮化物衍生物（N-FeMnNi）。值得注意的是，当在1.0 M KOH水溶液中操作时，所得的PBA @ MnO ₂-150/30（其中150和30分别代表制备的水热温度（°C）和K ₃ Fe（CN）₆（mM）的浓度）显示出最出色的OER活性，在200伏时的超电势为238毫伏。 10 mA cm ^-2。此外，N-FeMnNi-130 / 10需要101 mV的过电势才能达到HER的10 mA cm ^-2。结果，将两个样品组织起来以建立双电极电池，仅需1.60 V的电压即可达到10 mA cm ^-2。同时，它可以稳定工作30小时，而不会出现明显的电流衰减。这项工作为PBA电催化剂的高效整体水分解设计提供了崭新的视角。