High activity of g-C3N4/multiwall carbon nanotube in catalytic ozonation promotes electro-peroxone process

Three kinds of graphitic carbon nitride materials (bulk, porous and nanosheet g-C3N4) were composited with a multiwall carbon nanotube (MWCNT) by a hydrothermal method, and the obtained b-C3N4/CNT, p-C3N4/CNT and n-C3N4/CNT materials were used in the electrodes for electro-peroxone process. It was found that the n-C3N4/CNT composite exhibited the highest efficiency in oxalate degradation, though it performed the worst in the oxygen-reduction reaction for H2O2 production. The n-C3N4/CNT composite exhibited higher activity than CNT and other composites in catalytic ozonation experiments, due to the higher pyrrolic-N content modified on the CNT surface and higher surface area. It also has higher electron transfer ability, which benefited to the electro-reduction of both O2 and O3. The result confirmed that catalytic ozonation process was an important means to enhance the degradation efficiency in the electro-peroxone process, besides peroxone process and O3-electrolysis.