Abstract:Using urea and ammonium bromide as precursor and bromine source, respectively, and ascorbic acid was used to modify g-C3N4. The ascorbic acid modified Br-doped g-C3N4-AA-Br nanosheets photocatalyst was successfully prepared through secondary roasting. The structure, morphology and optical properties of the catalysts were characterized by XRD, TEM, XPS, UV-Vis DRS, PL, N2 adsorption-desorption and other test methods. The results show that g-C3N4-AA-Br had larger specific surface area, wider visible light absorption range and lower electron-hole recombination rate. The photocatalytic performance of different catalysts on the degradation of rhodamine B, methyl orange, and reactive blue dyes was investigated under visible light. The results showed that g-C3N4-AA-Br-2 increased the degradation of RhB by 72% within 180minutes, and its rate constant k=0.00847min-1, which is 5.6 times that of pure g-C3N4. Through the active species trapping agent experiment, it is found that the main active species that degrade RhB are hydroxyl radicals(·OH) and superoxide radicals(·O2-), and the possible reaction mechanism is speculated.
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