Conversion of rice husk biomass into electrocatalyst for oxygen reduction reaction in Zn-air battery: Effect of self-doped Si on performance

•A highly active Si-Fe/S/N-RH3 oxygen reduction reaction electrocatalyst is developed from rice husk.•Self-doped Si in rice husk that can efficiently improve oxygen reduction reaction activity is proved.•One of the best performances among the biomass-derived electrocatalysts is achieved.