A Mechanochemical-Assisted Synthesis of Boron,Nitrogen Co-Doped Porous Carbons as Metal-Free Catalysts |
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Authors: | Li-Yuan Zhao Xiao-Ling Dong Jun-Yue Chen Prof Dr An-Hui Lu |
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Institution: | State Key Laboratory of Fine Chemicals, School of Chemical Engineering, Dalian University of Technology, No. 2 Linggong Road, Ganjingzi District, Dalian City, Liaoning Province, 116024 P.R. China |
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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 m2 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. |
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Keywords: | B N co-doped carbon cooperative effects mechanochemical methods metal-free catalysis solid-state synthesis |
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