Highly Active Black TiO2/N‐doped Graphene Quantum Dots Nanocomposites For Sunlight Driven Photocatalytic Sewage Treatment

Abstract In this manuscript, we demonstrated that black TiO 2‐x /N‐doped graphene quantum dots (BTNG) nanocomposite photocatalysts exhibit extremely high photocatalytic activity while degradating Rhodamine B (RhB) dye and other common organic species (>15 species were tested). The kinetic constant is 0.86 min −1 under the irradiation of simulated sunlight, which is the highest among all the reported values of TiO 2 based photocatalysts. The photocurrent intensity can reach 2.7 mA cm −2 , indicating the excellent separation efficiency of the electrons and holes. The BTNG photocatalysts can decompose most of organic pollutants in the industrial sewage, with the total organic carbon (TOC) decreasing from 370 mg to 57 mg under 30 mins sunlight irradiation. The BTNG also has good stability and cycling performance. Possible mechanisms for the high photocatalytic performance of BTNG were proposed and discussed.