Systematic constructing CoFe-Prussian blue analogue on NiCo-layered double hydroxide to obtain heterostructure two-bimetallic phosphide composite as efficient self-supported eletrocatalyst for overall water and urea electrolysis

It remains a challenge to explore economical, high-effective and long term stability electrocatalysts toward large-scale hydrogen production. This work utilizes surface engineering strategy to in-situ CoFe-Prussian Blue Analogues on NiCo-layered double hydroxides to obtain 3D hierarchical heterostructure precursor (NiCo-CoFe-PBA). After phosphatization, this precursor can be further transform into tri-metallic phosphide (NiCoP/CoFeP@NF) and directly act as efficient self-supported electrode for Water and Urea Electrolysis. Impressively, the obtained NiCoP/CoFeP@NF-12 (+/-) electrode shows excellent catalytic performance with only requires the cell voltage of 1.61 and 1.46 V to deliver 10 mA cm-2 in overall water splitting and urea electrolysis, respectively, which benefiting from the porous Ni foam (NF) substrate, large catalytic activity area, remarkable mass/electron transfer property, the synergistic effect of components as well as superhydrophilicity and superaerophobicity of electrode surface. In addition, the experimental results also confirm that urea-assisted system has energy saving advantage superior than traditional water splitting in alkaline electrolyte. Moreover, the hierarchical strategy can also be introduced to the construction of other intricate composites for the utilization in energy conversion and storage. (c) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study successfully synthesized a 3D hierarchical heterostructure precursor on NiCo-layered double hydroxides through surface engineering strategy, which can be further transformed into a tri-metallic phosphide with excellent catalytic performance. Additionally, urea-assisted system was found to have energy saving advantage superior to traditional water splitting in alkaline electrolyte.