Defect engineering in oxides by liquid Na-K alloy for oxygen evolution reaction

Defect engineering in oxides can effectively modulate their electric states and offers more active sites for electrocatalytic reactions. However, creating oxygen defects often require high processing temperatures or long-time consumption. Here, we exploited a simple and universal method to create defects in several metal oxides such as Co 3 O 4 , ZnO, SnO 2 , and CeO 2 using highly active liquid sodium-potassium (Na-K) alloy as the reducing agent at room temperature. To verify the available potential of this synthetic strategy, we choose defective Co 3 O 4 as an example and investigate its oxygen evolution reaction (OER) performance. The oxygen vacancies have a significant promotion effect on the OER activity and its starting potential is 1.54 V with a Tafel slope of 47.9 mV/dec, which is much lower than pristine Co 3 O 4 nanoparticles. Our method of creating defects in oxides may be used for many other related applications.