Photocatalytic Nitrogen Reduction for Ammonia Synthesis Accelerated by Overcoming Photo-Dember Effect

During photocatalytic nitrogen fixation for ammonia synthesis, the photo-Dember effect causes direct transmission of photogenerated electrons from the illuminated surface to the bottom of photocatalyst, thus significantly reducing the number of charge carriers migrating on the surface and nitrogen fixation efficiency. Herein, a bismuth oxychloride material with largely exposed (101) crystal plane and rich oxygen vacancies (BOC₍₁₀₁₎-OVs) is synthesized, exhibiting a high NH₃ yield of 591.94 µmol g^-1 h^-1) after photocatalytic N₂ reduction under simulated solar light irradiation. The designed (101)/(001) interface in BOC₍₁₀₁₎-OVs generates a self-built electric field (E_self) on the material surface due to different atomic arrangements. Therefore, the newly developed material achieved >95% of photogenerated electrons changing the transfer path, i.e., from bulk phase transfer to surface lateral transfer path, thus escaping confinement by the photo-Dember effect. Meanwhile, after OVs construction, each adsorbed N₂ molecule simultaneously bonds with three Bi atoms of material through N 2p-Bi 6p bonding, accelerating the filling of high-energy electrons into the π* orbital of N₂, leading to a new nitrogen reduction path with combined alternating hydrogenation and terminal hydrogenation. This study greatly advances the beneficial effect of charge carrier migration through overcoming the photo-Dember effect for ammonia synthesis.