Self‐Anti‐Stacking 2D Metal Phosphide Loop‐Sheet Heterostructures by Edge‐Topological Regulation for Highly Efficient Water Oxidation

Abstract 2D metal phosphide loop‐sheet heterostructures are controllably synthesized by edge‐topological regulation, where Ni₂P nanosheets are edge‐confined by the N‐doped carbon loop, containing ultrafine NiFeP nanocrystals (denoted as NiFeP@NC/Ni₂P). This loop‐sheet feature with lifted‐edges prevents the stacking of nanosheets and induces accessible open channels for catalytic site exposure and gas bubble release. Importantly, these NiFeP@NC/Ni₂P hybrids exhibit a remarkable oxygen evolution activity with an overpotential of 223 mV at 20 mA cm⁻² and a Tafel slope of 46.1 mV dec⁻¹, constituting the record‐high performance among reported metal phosphide electrocatalysts. The NiFeP@NC/Ni₂P hybrids are also employed as both anode and cathode to achieve an alkaline electrolyzer for overall water splitting, delivering a current density of 10 mA cm⁻² with a voltage of 1.57 V, comparable to that of the commercial Pt/C||RuO₂ couple (1.56 V). Moreover, a photovoltaic–electrolysis coupling system can as well be effectively established for robust overall water splitting. Evidently, this ingenious protocol would expand the toolbox for designing efficient 2D nanomaterials for practical applications.