Nitrogen-Doped Porous Graphene-like\nCarbon Nanosheets as Efficient Oxygen Reduction Reaction Catalysts\nunder Alkaline and Acidic Conditions

Abstract

Electrocatalysts\nare vulnerable to be\ninfluenced during the oxygen reduction reaction (ORR) process on the\ncathodes of direct methanol fuel cells, mainly by the reaction products\nand air-containing traces of acidic gas carbon dioxide (CO₂), leading to low activity and durability. Herein, an ORR catalyst\nwas derived from furfural, nitrogen carbide (g-C₃N₄), and calcium chloride (CaCl₂) via a dual-template\nmethod, resulting in two-dimensional graphene-like carbon nanosheets\nwith a micro–mesoporous architecture, large Brunauer–Emmett–Teller\nsurface areas (748 m²/g), an ultrahigh pyridinic nitrogen-doping\nlevel (13.6 wt %), and high degree of graphitization. The as-synthesized\nsample shows high ORR performance and robust durability in both alkaline\nand acidic electrolytes undergoing a gas mixture of O₂ and\nCO₂ (95:5), demonstrating a strong tolerance of CO₂ during the ORR process. Besides, the as-prepared material\nalso exhibits competitive properties in the selective capture of CO₂ gas versus N₂. Thus, this work provides a facile\nroute of preparing high-performance bifunctional carbonaceous materials\nin both ORR and CO₂ gas capture.