Efficient carbon-based catalyst derived from natural cattail fiber for hydrogen evolution reaction

Metal-free electrocatalysts for hydrogen evolution reaction (HER) are very important for efficient supply of sustainable and clean fuel. Herein, metal-free N-doped porous carbon fibers (NPCF) is reported by carbonization, activation and nitrogen-doping of natural cattails. The carbon fibers possess high specific surface area (765 m(2) g(-1)) and lots of micropores. Excellent catalytic performances of NPCF are illustrated for HER from electrolysis of water in acidic media. An onset overpotential of 70 mV with a low Tafel slope of 135 mV.dec(-1) was observed for NPCF electrode. The electrocatalytic properties of NPCF are much better than those of commercial graphite powder, carbon nanotubes and super-P. NPCF also shows promising electrochemical durability with only 3% recession of current density after 20 h continuous operations. The high catalytic activities of NPCF are attributed to the relatively high specific surface area, abundant micropores, strong electrical conductivity, the high stability of biomass-derived carbon matrix and suitable N content. The preparation and high activities for HER of NPCF offer a novel idea for the promising preparation of metal-free carbon materials derived from earth-abundant biomass for more efficient and cleaner bulk chemical production.