A sulfur self‐doped multifunctional biochar catalyst for overall water splitting and a supercapacitor from Camellia japonica flowers

Abstract A versatile use of a sulfur self‐doped biochar derived from Camellia japonica (camellia) flowers is demonstrated as multifunctional catalyst for overall water splitting and supercapacitor. The native content in the camellia flower facilitates situ self‐doping sulfur, which highly activates camellia‐driven (SA‐Came) with enhanced electron‐transfer ability long‐term durability. For splitting, an SA‐Came‐based electrode stable shows reaction activities both hydrogen oxygen evolution reactions, overpotentials 154 362 mV at 10 mA cm −2 , respectively. supercapacitors, SA‐Came achieves specific capacitance 125.42 F g −1 2 high cyclic stability three‐electrode system 1 M KOH electrolyte. It energy density 34.54 Wh kg power 1600 W symmetric hybrid supercapacitor device wide working potential range 0–1.6 V.