Engineering Dense Stacking Faults in Silver Nanoparticles for Boosting the Oxygen Reduction Reaction

Defect engineering is an efficaciousstrategy for optimizingtheactivity of catalysts, while traditional chemical synthesis has limitedability to generate a large number of defects due to the mild andequilibrium conditions. In this work, we show that a physical process,laser ablation in liquid, can prepare Ag nanoparticles with controllabledefects due to its extremely nonequilibrium conditions. Particularly,the liquid nitrogen medium helps form abundant stacking faults whichreduce the coordination number greatly and introduce high latticetensile strain; these two factors jointly enhance the oxygen bindingenergy of Ag nanoparticles and significantly improve the ORR activityto an extent comparable to commercial Pt/C. When the Ag catalyst isapplied in Zn-air batteries, the power density could reach 262.85mW cm(-2), much better than those of Pt/C and otherreported Ag-based catalysts.