Photocatalytic degradation of methylene blue over boron-doped g-C3N4 together with nitrogen-vacancies under visible light irradiation

For highly efficient photodegradation of organic pollutants, the enhancement of photocatalytic activity of metal-free photocatalyst graphitic carbon nitride (g-C 3 N 4 ) under visible light irradiation is meaningful, but still challenging due to the fast recombination of photogenerated electron–hole pairs, low quantum efficiency and specific surface area of pristine g-C 3 N 4 . To address these challenges, boron-doped g-C 3 N 4 together with nitrogen-vacancies (Bd-Nv-C 3 N 4 ) was designed and synthesized through a simple acid-assisted calcination of melamine without any further tedious operations. As expected, based on the synergistic effect of foreign elements doping (boron atoms doping) and intrinsic defects (nitrogen vacancies), the as-prepared novel Bd-Nv-C 3 N 4 photocatalyst shows lower band gap, higher surface area and separation efficiency of photogenerated electron–hole pairs, achieving a nearly tenfold increase of the phtocatalytic constant for methylene blue (MB) degradation compared to that of pristine g-C 3 N 4 without nitrogen-vacancies and boron-doping. This study provides a new train of thought and method for the design and preparation of nonmetal photocatalysts with enhanced visible light irradiation photocatalytic performance.