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A Mechanochemical‐Assisted Synthesis of Boron, Nitrogen Co‐Doped Porous Carbons as Metal‐Free Catalysts
Author(s) -
Zhao LiYuan,
Dong XiaoLing,
Chen JunYue,
Lu AnHui
Publication year - 2020
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201904381
Subject(s) - catalysis , boron , boric acid , x ray photoelectron spectroscopy , carbon fibers , mesoporous material , metal , materials science , inorganic chemistry , transition metal , nitrogen , chemistry , nuclear chemistry , chemical engineering , organic chemistry , composite number , metallurgy , engineering , composite material
A green and convenient solid‐state method assisted by mechanical energy is employed for the synthesis of boron (B) and nitrogen (N) co‐doped porous carbons (B,N‐Cs). Glutamic acid (Glu) and boric acid (H 3 BO 3 ) are used as the N‐containing carbon precursor and boron source, respectively. This method is easy to perform and proved to be efficient towards co‐doping B and N into the carbon matrix with high contents of B (7 atom %) and N (10 atom %). By adjusting the molar ratio of H 3 BO 3 to Glu, the surface chemical states of B and N could be readily modulated. When increasing H 3 BO 3 dosage, the pore size of B,N‐Cs could be tuned ranging from micropores to mesopores with a Brunauer–Emmett–Teller (BET) surface area up to 940 m 2 g −1 . Finally, the B,N‐Cs were applied as metal‐free catalysts for the cycloaddition of CO 2 to epoxides, which outperform the N‐doped carbon catalyst (NC‐900) and the physically mixed catalyst of NC‐900/B 4 C. The enhanced activity is attributed to the cooperative effect between B and N sites. X‐ray photoelectron spectroscopy (XPS) analysis reveals that BN 3 in the B,N‐Cs serves as a critical active site for the cooperative catalysis.