Nitrogen,\nSulfur Co-Doped Hierarchically Porous Carbon as a Metal-Free Electrocatalyst\nfor Oxygen Reduction and Carbon Dioxide Reduction Reaction

Abstract

High-cost\nand low-efficiency electrocatalysts have hindered oxygen reduction\nreaction (ORR) in fuel cells and CO₂ reduction reaction\n(CO₂RR) for producing fuels and value-added chemicals.\nHere, a low-cost metal-free electrocatalyst of a N, S co-doped hierarchically\nporous carbon (NSHPC) for efficient ORR and CO₂RR is reported.\nThe NSHPC is prepared by pyrolysis of glucosamine hydrochloride and\nthiocyanuric acid precursors using SiO₂ as hard templates.\nThe N, S co-doping effectively enhances catalytic activity and selectivity,\nand the hierarchically porous structure largely exposes abundant active\nsites to reaction species and facilitates electrolyte transport, thereby\nleading to significantly increased catalytic activities for the NSHPC.\nThe resultant NSHPC exhibits excellent electrocatalytic activities\ntoward ORR in both acidic and alkaline electrolytes and also shows\napplication in proton exchange membrane fuel cells (PEMFCs). More\nimportantly, the NSHPC enables CO₂ reduction to CO with\n87.8% maximum Faraday efficiency (FE) in aqueous electrolytes. This\nwork offers a novel insight into the development of multifunctional\nelectrocatalysts for producing electricity, fuels, and value-added\nchemicals.