Photocatalytic O2 activation and reactive oxygen species evolution by surface B-N bond for organic pollutants degradation

The efficiency of photocatalytic molecular oxygen (O2) activation is limited by the poor O2 adsorption and the obstruction of electron transfer. Herein, we designed a graphite carbon nitride with surface B-N bond (Bx-C3N4) to improve its efficiency. A series of characterizations and DFT calculations show that boron atom replaces carbon atom to form B-N bond, which increase the O2 adsorption energy from − 0.47 eV to − 1.17 eV. Moreover, the doped boron atom can be used as the electron capture center to transfer electrons to the N atom, then to the surface adsorbed O2 through the N-O bond, thus improving the photocatalytic generation of·O2- and 1O2. Finally, the photocatalytic degradation rates of RhB, tetracycline and o-nitrophenol by B0.05-C3N4 are 12.3, 4.8 and 18.5 times that of pure g-C3N4, respectively. Moreover, the degradation pathway and toxicity prediction of intermediates of RhB are proposed based on the results of HPLC-MS and DFT calculations.