Electrochemical preparation of bismuthene quantum dots for the selective electroreduction of O₂ to peroxide

Bismuthene quantum dots (BiQDs), as a zero-dimensional (0D) material, offer significant potential in electrocatalysis due to their quantum confinement, edge effects, and unique electronic structure. Herein, we report a facile electrochemical exfoliation strategy for the synthesis of crystalline BiQDs (lateral dimensions of 2.2 nm) in N-methylpyrrolidone (NMP) at room temperature. Their electrocatalytic activity towards the oxygen reduction reaction (ORR) in alkaline media is systematically evaluated. The observed Tafel slope of approximately 40 mV dec^-1 and the high exchange current density (6.0 × 10^-8 A cm^-2) indicate notable kinetic improvements over conventional Pt-based electrocatalysts and enhanced cycling stability. BiQDs exhibit enhanced ORR performance following a two-electron transfer mechanism. This work highlights the promising role of BiQDs as efficient and environmentally friendly ORR electrocatalysts.