Spinach-Derived Porous Carbon Nanosheets as High-Performance\nCatalysts for Oxygen Reduction Reaction

Abstract

Biomass-derived\nporous carbon materials are effective electrocatalysts\nfor oxygen reduction reaction (ORR), with promising applications in\nlow-temperature fuel cells and metal–air batteries. Herein,\nwe developed a synthesis procedure that used spinach as a source of\ncarbon, iron, and nitrogen for preparing porous carbon nanosheets\nand studied their ORR catalytic performance. These carbon sheets showed\na very high ORR activity with a half-wave potential of +0.88 V in\n0.1 M KOH, which is 20 mV more positive than that of commercial Pt/C\ncatalysts. In addition, they showed a much better long-term stability\nthan Pt/C and were insensitive to methanol. The remarkable ORR performance\nwas attributed to the accessible high-density active sites that are\nprimarily from Fe–N_<i>x</i> moieties.\nThis work paves the way toward the use of metal-enriching plants as\na source for preparing porous carbon materials for electrochemical\nenergy conversion and storage applications.