Pristine‐Graphene‐Supported Nitrogen‐Doped Carbon Self‐Assembled from Glucaminium‐Based Ionic Liquids as Metal‐Free Catalyst for Oxygen Evolution

Abstract

For the first time, graphene‐supported N‐doped carbon (G@NC) with a high degree of N doping was synthesized by in situ self‐assembly of a glucaminium‐based ionic liquid on pristine graphene under hydrothermal conditions. This 2D, metal‐free nanohybrid exhibited much higher catalytic activity than most reported metal‐free catalysts for the oxygen evolution reaction (OER) and even state‐of‐the‐art Ir‐ and Ru‐based catalysts because the high content of graphitic N greatly increased the number of OER‐active sites, the pristine graphene significantly promoted the OER activity of the C sites adjacent to the graphitic N atoms, and N‐doped graphitic carbon remarkably enhanced the charge‐transfer rate. This work not only creates a facile and economical approach to controllably fabricate pristine‐graphene‐supported carbon with a high N‐doping level for the development of highly efficient metal‐free OER catalysts but also provides insight into the mechanisms for both the in situ self‐assembly and the high OER catalytic activity of G@NC.

Non‐N‐Doped Carbons as Metal‐Free Electrocatalysts

“…Even so, we summarize the best performance for various reactions catalyzed by different heteroatoms‐doped carbons in Figure for easy comparison. [ 118–158 ] As can be seen, N‐doped carbon catalysts show better catalytic performance over other heteroatom‐doped carbons for ORR and water splitting. For non‐N‐doping, only B‐doping has been reported for ORR, P‐doping for OER, and F‐doping for HER to show catalytic performance comparable to the N‐doping.…”

Bioderived Ionic Liquids and Salts with Various Cyano Anions as Precursors for Doped Carbon Materials

“…In addition to the continuous search for useful biomass feedstock and ecofriendly processes suitable for its derivatization, products such as bio-derived solvents, additives, and functional materials are also of special interest. In this regard, bio-derived ionic liquids (ILs) [ 1 , 2 , 3 ] that can serve as solvents for the biomass dissolution desirable in the closed-loop biorefinery concept [ 4 ], as solvents for ionothermal biomass upgrading into functional carbon materials, or as carbon precursors themselves [ 5 , 6 , 7 ] can be useful sustainable chemicals.…”

“…They combine the properties of biomass, such as high carbon content, with the properties of ILs, including high thermal stability, low vapor pressure, and nitrogen-rich molecular structures. Under thermal treatment, N atoms can be uniformly introduced into the carbon structure during the in situ self-assembly process [ 6 ]. Various feedstocks, including amino acids [ 7 , 15 , 16 ], carbohydrates [ 5 ], glucamine [ 6 ], alginic acid [ 17 ], cellulose [ 18 ], and furfurylamine [ 19 ], have been transformed into ILs and further utilized as N-doped carbon precursors.…”

“…Under thermal treatment, N atoms can be uniformly introduced into the carbon structure during the in situ self-assembly process [ 6 ]. Various feedstocks, including amino acids [ 7 , 15 , 16 ], carbohydrates [ 5 ], glucamine [ 6 ], alginic acid [ 17 ], cellulose [ 18 ], and furfurylamine [ 19 ], have been transformed into ILs and further utilized as N-doped carbon precursors. Via precise design of the structure of the precursors at the molecular level, the final properties of the carbonaceous material, such as the N-doping level, carbonization yield, and the surface properties, can be controlled [ 5 , 20 ].…”

Dicyanamide Anion-Based Ionic Liquid-Functionalized Graphene-Supported Pt Catalysts for Boosting Methanol Electrooxidation

“…He et al took the Fe-based ILs as the precursors of Fe–N–C, and the participation of ILs not only provided the N source but also improved the dispersions of Fe particles . The noncovalent functionalization of graphene by ILs can improve its match with other materials and enhance its conductivity in practical applications. − IL-functionalized graphene can accelerate the charge transfer path to greatly boost the electrocatalytic performance and stability of the Pt-based composite catalyst for MOR. − Furthermore, the presence of ILs could stabilize the metal nanoparticles for high catalytic properties . Generally, tetrafluoroborate anionic ILs are well known and commonly used, for example, they are mainly studied to functionalize graphene using 1-ethyl-3-methylimidazolium tetrafluoroborate (emimBF 4 ) owing to its high conductivity and stability .…”