The synthesis of highly activity, stable and cost-effective electrocatalysts for overall water splitting is critical but challenging. Herein, we synthesized the nickel-doped pyrrhotite iron sulfide (Fe0.95−xNixS1.05) nanosheets via a one-pot...

Electronic structure modulation among multiple metal sites is key to the design of efficient catalysts. Most studies have focused on regulating 3d transition-metal active ions through other d-block metals, while few have utilized f-block metals. Herein, we report a new class of catalyst, namely, UCoO 4 with alternative CoO 6 and 5f-related UO 6 octahedra, as a unique example of a 5f-covalent compound that exhibits enhanced electrocatalytic oxygen evolution reaction (OER) activity because of the presence of the U 5f−O 2p−Co 3d network. UCoO 4 exhibits a low overpotential of 250 mV at 10 mA cm −2 , surpassing other unitary cobalt-based catalysts ever reported. X-ray absorption spectroscopy revealed that the Co 2+ ion in pristine UCoO 4 was converted to high-valence Co 3+/4+ , while U 6+ remained unchanged during the OER, indicating that only Co was the active site. Density functional theory calculations demonstrated that the OER activity of Co 3+/4+ was synergistically enhanced by the covalent bonding of U 6+ -5f in the U 5f−O 2p−Co 3d network. This study opens new avenues for the realization of electronic structure manipulation via unique 5f involvement.

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