Construction of molecularly doped and cyano defects co-modified graphitic carbon nitride for the efficient photocatalytic degradation of tetracycline hydrochloride†
Abstract
The structural modulation of graphitic carbon nitride (g-C3N4) is regarded as an effective strategy to boost its photocatalytic behavior. Herein, we have synthesized 4,6-dimethyl-2-hydroxypyrimidine-doped and cyano defects co-modified graphitic carbon nitride (HDMP–CD-g-C3N4) using a facile in situ co-condensation method. HDMP–CD-g-C3N4 was employed for the degradation of tetracycline hydrochloride, exhibiting enhanced photocatalytic activity and catalyst stability. The characterization results demonstrate that the doping of HDMP decreases the band gap, thus promoting the light absorption of g-C3N4. Meanwhile, as an electron acceptor, HDMP broadens the π-conjugated off-domain system and accelerates the transfer of photogenerated electrons. In addition, the introduction of cyano defects further improves the separation efficiency of photogenerated electrons and holes. Analysis of time-resolved fluorescence spectra solidly supports these conclusions. Therefore, the photocatalytic degradation rate of HDMP–CD-g-C3N4 was 3.8 times that of the original g-C3N4, 2 times that of HDMP-doped g-C3N4 (HDMP-g-C3N4) and 2.5 times that of cyano defects-modified g-C3N4 (CD-g-C3N4). This work provides a way for collaboratively modulating the structure of g-C3N4 with molecular doping and defects, which is expected to bring novel prospects for the application of g-C3N4 in the treatment of waste water.