Defect modulation and in‐situ exsolution in Y 2 Ru 2 O 7 @NiFeP/Ru heterostructure for enhanced oxygen evolution reaction

Abstract Pyrochlore oxide (Y 2 Ru 2 O 7 ) has been identified as a promising catalyst for the oxygen evolution reaction (OER) in advanced green energy strategies. However, its electrochemical inertness necessitates the exploration of an effective strategy to facilitate electronic modulation. This study proposes a surface modification approach involving the integration of defective NiFe (D‐NiFe) nanoparticles onto a Y 2 Ru 2 O 7 (YRO) support (YRO@D‐NiFeP/Ru) using a Prussian blue analog (PBA). Numerous cyanide (CN) vacancies are generated through the oxidation treatment of the NiFe PBA grown on the YRO support, yielding a defective PBA precursor (YRO@D‐PBA). Subsequent annealing facilitates the transformation to the D‐NiFe nanoparticles on the YRO support (YRO@D‐NiFeP/Ru), which augments the exposure of Ni 3+ active sites beneficial for the OER. Moreover, the reduction of Ru cations from YRO results in the exsolution of Ru nanoparticles, which promotes synergistic charge transfer from the nanoparticles to the interior of Y 2 Ru 2 O 7 . Consequently, YRO@D‐NiFeP/Ru exhibits a remarkable voltage of 1.49 V at 10 mA·cm −2 and the lowest Tafel slope of 42.4 mV·dec −1 . In addition, a Zn–air battery constructed with YRO@D‐NiFeP/Ru exhibits an outstanding power density of 136.2 mW·cm −2 and high charge–discharge stability, confirming the applicability of YRO@D‐NiFeP/Ru in metal‐air batteries.