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

The efficiency of photocatalytic molecular oxygen (O-2) activation is limited by the poor O-2 adsorption and the obstruction of electron transfer. Herein, we designed a graphite carbon nitride with surface B-N bond (B-x-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 O-2 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 O-2 through the N-O bond, thus improving the photocatalytic generation of center dot O-2(-) and O-1(2). Finally, the photocatalytic degradation rates of RhB, tetracycline and o-nitrophenol by B-0.05-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.

Automated summary

By designing B-x-C3N4 material, the efficiency of photocatalytic activity is greatly improved due to the enhanced O-2 adsorption energy and electron transfer efficiency. This leads to a significant enhancement in photocatalytic degradation.