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Indexed by:Journal Papers

Date of Publication:2020-02-11

Journal:CHEMISTRY-A EUROPEAN JOURNAL

Included Journals:PubMed、EI、SCIE

Volume:26

Issue:9

Page Number:2041-2050

ISSN No.:0947-6539

Key Words:B; N co-doped carbon; cooperative effects; mechanochemical methods; metal-free catalysis; solid-state synthesis

Abstract: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 (H3BO3) 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 H3BO3 to Glu, the surface chemical states of B and N could be readily modulated. When increasing H3BO3 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 CO2 to epoxides, which outperform the N-doped carbon catalyst (NC-900) and the physically mixed catalyst of NC-900/B4C. The enhanced activity is attributed to the cooperative effect between B and N sites. X-ray photoelectron spectroscopy (XPS) analysis reveals that BN3 in the B,N-Cs serves as a critical active site for the cooperative catalysis.