Preparation of carbon self-doped g-CN for efficient degradation of bisphenol A under visible light irradiation.

In this study, visible-light-driven carbon self-doped graphitic carbon nitride photocatalyst was fabricated by a facile method with urea and ammonium citrate, and used for photodegradation of bisphenol A (BPA) in the aqueous environment. The experiments indicated that the prepared photocatalyst (CCN) showed high catalytic activity, and 96.0%, 93.2%, and 95.5% BPA could be photodegraded in 150 min under pH 3, 6, and 11, respectively. The photocatalytic degradation rate (0.018 min) and mineralization (27.6%) of CCN for BPA were about 6.7 and 3.5 times higher than those of the g-CN (0.0027 min, 7.87%), respectively. CCN had high reusability with a photodegradation efficiency of 84.5% for BPA after 3 cycles. Moreover, CCN introduced additional carbon atoms, which generated C-O-C bonds in the g-CN lattice. In contrast to g-CN, carbon doping enhanced the visible light absorption range of CCN, reduced its band gap, and improved the separation efficiency of photogenerated electron-hole pairs. Radical quenching experiment and ESR results revealed that superoxide radicals (•O) and photogenerated holes (h) acted as important parts in the high photodegradation activity under visible light irradiation. This work puts forward a one-pot strategy for the preparation of carbon self-doped g-CN, displacing the high-energy consuming and complicated preparation technology with promising industrial applications.