With proper conjunctions between inter/intra-particle domains, the activity and durability of heterogeneous nanocatalysts (NCs) can be substantially improved by more than an order. In this study, tri-metallic NCs comprising an Ir-clusters decorated unconformable Pd-shell over amorphous NiOx core crystal underneath (namely NPI) are developed for oxygen reduction reaction (ORR) in alkaline medium (0.1 M KOH). Results for NPI NCs with different extents of Ir decoration (1 and 14 wt%) are compared for clarifying the configuration effects corresponding to ORR performance. For the optimum case with an Ir loading of ∼1.0 wt%, the mass activity (MA) is 2066.8 mAmg−1. This value is ∼31-folds increased as compared to that of commercial J.M.-Pt/C catalyst (20 wt% Pt) at 0.85 V vs RHE (67.1 mA mg−1). Moreover, as prepared NPI-0025 NC exhibits nearly 100% stability when operated up to 21 k accelerated degradation test (ADT) cycles. By cross-referencing results of physical structure inspections and electrochemical analysis, we reveal that such a high ORR performance could be attributed to the incorporation of Ir atoms in defect sites of Ni–Pd interfaces. These Ir atoms facilitate the O2 splitting by electronegativity differences to the adjacent sites, therefore, improves the ORR performance of NPI NCs.
- Oxygen reduction reaction
- Wet chemical reduction method