Nitrogen-doping-induced electron spin polarization activates scandium oxide as high-performance zinc-air battery...

Platinum (Pt) is the most active catalyst for the oxygen reduction reaction (ORR). However, the scarcity, high cost, and susceptibility to deactivation of Pt constrain its large-scale applications. Transition metal oxide (TMO) materials have emerged as promising alternatives due to their abundant availability and catalytic potential. Herein, we report a dissolution-and-carbonization strategy to synthesize a carbon-supported nitrogen-doped Sc₂O₃ catalyst (N-Sc₂O₃/C). Nitrogen doping significantly enhances the conductivity of the otherwise poor-conductivity Sc₂O₃, transforming it into a superior ORR catalyst. The synthesized N-Sc₂O₃/C exhibits remarkable ORR performance in 0.1 M KOH, achieving a half-wave potential of 0.92 V, which is 55 mV higher than the state-of-the-art commercial Pt/C (0.87 V). Moreover, as a cathode for a zinc-air battery, N-Sc₂O₃/C achieves a peak power density of 150.7 mW cm^-2 and a specific capacity of 766.4 mAh g_Zn^-1. Density functional theory calculations reveal that nitrogen doping induces electron spin polarization within Sc₂O₃, narrowing the bandgap. This enhanced electronic structure improves conductivity and optimizes the adsorption of oxygen intermediates, thereby facilitating the ORR process. Our study demonstrates that nitrogen doping activates the wide-bandgap Sc₂O₃ semiconductor, converting it into a highly efficient ORR electrocatalyst and highlighting the potential of wide-bandgap TMO materials in energy applications.