Preparation of a C3N4 photocatalyst and its degradation of tetracycline antibiotics
In this study,C3N4 was fabricated by thermal polymerization using a single urea as a precursor,for which the structure,composition,optical properties and photocatalytic activity of the prepared C3N4 materials were characterized by SEM,XRD,XPS,FT-IR and UV-Vis analyses.The as-fabricated C3N4 was found to display a flower-like porous nanosheet structure and a large specific surface area.The C3N4 exhibited good photocatalytic activity for the degradation of tetracycline hydrochloride(TCH)under the irradiation of xenon lamp at 320～780nm,and the degradation rate reached 99.60％within 60min.The results of free radical quenching experiments showed that*O2、1O2 and h+were the main causes of TCH degradation.Further analysis by comparative tests and DFT theoretical calculations revealed that the superior photocatalytic effect of C3N4 prepared from urea than M-C3N4 prepared from melamine was attributed to the flower-like porous structure of C3N4 with larger specific surface area for more active sites and oxygen vacancies.Furthermore,the prepared catalyst C3N4 showed similar catalytic effect on tetracycline-based antibiotics(chrysomycin hydrochloride(CTC)and oxytetracycline(OTC)).Further,the possible degradation pathways of TCH were proposed by analyzing the photocatalytic oxidation intermediates.
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