Enhanced photocatalytic nitrogen fixation of Ag/B-doped g-C3N4 nanosheets by one-step in-situ decomposition-thermal polymerization method

Photocatalytic nitrogen fixation is considered as a promising strategy for ammonia production. In this study, non-metallic boron and noble metal silver modified graphitic carbon nitride were prepared by a direct in-situ decomposition-thermal polymerization method with dicyandiamide, boric acid and silver nitrate as the precursors. It was shown that Ag/B-doped g-C3N4 composites with optimal mass ratio exhibited improved photocatalytic ammonia production under simulated sunlight illumination by a factor of 5.5 and 1.5 times compared with the pristine g-C3N4 and B-doped g-C3N4, respectively. The superior photocatalytic property was attributed to the decreased band gap and formation of mesopores after boron doping, which enlarged the specific surface area and created abundant reactive sites on the g-C3N4 nanosheets. In addition, the loaded silver nanoparticles greatly inhibited the recombination of photogenerated charge carriers through heterojunction interface. This work provided new deep insights into the reasonable structure of g-C3N4 composite system for photocatalytic nitrogen fixation reactions.