Enhancing photocatalytic nitrogen fixation performance of Co-doped bismuth molybdate through band engineering tuning

• Co-doping can boost nitrogen reduction activity of Bi 2 MoO 6 microsphere with the NH 3 yield of 130.07 μmol·h −1 ·g cat -1. • The doping of Co 2+ can promoted the rapid separation and transfer efficiency of photogenerated carriers. • The more protons produced were beneficial to participate in the nitrogen reduction reaction. Energy band engineering strategy by doping has been extensively proved to have great influence on photocatalytic properties of semiconductors. Herein, a novel Co-doped Bi 2 MoO 6 (Co-BMO) photocatalyst was developed for photocatalytic nitrogen fixation. Co-BMO with microsphere structure was synthesized by a one-step solvothermal method. The NH 3 yield of 0.3 % Co-BMO (130.07 μmol·h −1 ·g cat −1 ) was about 3.9 times higher than that of pure BMO without scavengers and visible light irradiation. The band gap of 0.3 % Co-BMO was reduced and the average PL lifetime was improved due to the successful doping of Co 2+ , which directly led to higher separation efficiency of photogenerated carriers and improved photocatalyst activity. In addition, gas chromatography (GC) tests showed that 0.3 % Co-BMO had a higher photocatalytic oxygen production capacity, which meant that more protons would be involved in the nitrogen reduction reaction. Their synergistic effect greatly enhanced the photocatalytic nitrogen fixation ability of 0.3 % Co-BMO. This novel photocatalyst may be a promising candidate for photocatalytic nitrogen fixation.