Core–shell Prussian blue analogues derived from metal-organic frameworks as efficient electrocatalysts for oxygen evolution reaction

Developing high-performance and low-cost electrocatalysts for oxygen evolution reaction (OER) is still a great challenge for water-splitting technologies. Herein, an innovative metal-organic frameworks (MOFs) hybrid-assisted strategy is reported to synthesize core–shell Co/Mn-ZIF@Fe-Co-Mn Prussian blue analogues (PBAs) toward highly efficient OER electrocatalysts in alkaline electrolyte. Physical characterization indicates that the amorphous hydroxide transformed from Co/Mn-ZIF@Fe-Co-Mn PBA (ZIF: zeolitic imidazolate frameworks) during the electrochemical process acted as the electroactive species. Benefiting from these structural and compositional features, the developed composite delivers a remarkably low overpotential of 270 mV with a current density of 10 mA·cm⁻² in 1.0 M KOH solution. Moreover, water splitting is catalyzed to reach a current density of 10 mA·cm⁻² at 1.62 V.