Electrochemical splitting of water provides an attractive way to produce hydrogen fuel. Unfortunately, the efficient and large-scale H₂ production is still hindered by the sluggish kinetics of the oxygen evolution reaction (OER) at the anode side of a water electrolyzer. Starting from metal–organic frameworks (MOFs), we demonstrate a template-engaged strategy to transform Ni–Ni Prussian blue analogue (PBA) nanoplates into porous carbon coated nickel phosphides nanoplates with mixed phases of Ni₅P₄ and Ni₂P. For comparison, NiO and Ni(OH)₂ porous nanoplates with the similar morphology have also been synthesized from the same precursor. Benefitting from their structural merits and the in situ formed catalytically active oxidized nickel species, the as-derived nickel phosphides manifest excellent electrocatalytic activity for OER superior to NiO and Ni(OH)₂.

Rationally designed FeS ₂ @carbon yolk–shell nanoboxes exhibit impressive electrochemical performance when evaluated as an anode material for sodium-ion batteries.

The development of cost-effective and high-performance electrocatalysts for water oxidation has attracted intense research interest. It was reported recently that the interface between the amorphous and crystalline phases plays a significant role in the electrocatalytic activity of transition metal compounds. It was reckoned therefore that an increase in the density of the crystalline–amorphous phase boundary would enhance the electrochemical water oxidation on the catalyst. In this work we develop a new and facile strategy for inducing high density crystalline–amorphous phase boundaries via selective fluorination surface doping. This resulted in excellent characteristics of the engineered material for electrochemical water splitting. An initial computational simulation is carried out to design the crystalline–amorphous phase boundary material and an experimental verification follows for demonstration and optimization of the impact of surface doping. We conclude that the engineering of the interface using this facile and cost-effective strategy maximizes the crystalline and amorphous phases of metal–metalloids, which can be used to fabricate low-cost and efficient electrocatalysts for water oxidation.