Simultaneous Gd2O3 clusters decoration and O-doping of g-C3N4 by solvothermal-polycondensation method for reinforced photocatalytic activity towards sulfamerazine

To improve the visible-light photocatalytic activity of graphitic carbon nitrate (g-C3N4) for practical application, a Gd2O3-cluster decorated O-doping g-C3N4 was fabricated via an ethanol assisted solvothermalpolycondensation method. The as-prepared photocatalysts, including bulk g-C3N4 (CN), O-doping g-C3N4 (HECN) and Gd2O3-cluster decorated O-doping g-C3N4 (HECN-xGd), were characterized and the paralleled experiments were conducted to evaluate the photocatalytic activity, mineralization capacity and mineralization mechanism, where sulfamerazine (SMR) was employed as the target pollutant. Furthermore, the quenching tests with scavengers were executed to analyze the contributions of the dominant active species, where the center dot O-2- was identified as a major role, and h+ as the minor role in the photodegradation of SMR. Results from the paralleled experiments suggested that the HECN-xGd possesses superior photocatalytic activity to HECN and CN, besides the feasible reusability through five cycles and impressive total organic carbon (TOC) removal about 60%. And the improved photocatalytic activity of HECN-xGd is ascribed mainly to the oxygen doping and Gd2O3 decoration. Herein, oxygen doping optimizes the structure of g-C3N4 and expands the light absorption range of HECN, and Gd2O3 facilitates the reduction of O-2 into center dot O-2-, and acts as the separator and transporter for the photo -induced charges.