Photocatalytic or photoelectrocatalytic nitrogen fixation is considered as a very promising way to reduce energy requirements. Here, V_o-BiOBr/TiO₂ nanocomposite photoelectrode was constructed by modifying TiO₂ nanotube arrays with BiOBr nanosheets with oxygen vacancies (V_o) for photoelectrocatalytic nitrogen fixation. The oxygen vacancy promotes the adsorption and activation of N₂ on the catalyst surface. The Lewis basicity of nitrogen is enhanced by transferring the photogenerated electrons on the conduction band of BiOBr to the π anti-bonding orbit of N₂, which is more beneficial for the addition of protons. On the other hand, the heterojunction between TiO₂ and V_o-BiOBr facilitates the separation of photogenerated carriers. The photogenerated holes on the valence band of TiO₂ travelled to the counter electrode to produce oxygen at a negative potential, avoiding the further oxidation of NH₃. V_o-BiOBr/TiO₂ displays a high NH₃ production rate of 25.08 μg h⁻¹ cm⁻² at −0.2 V which is 3.3 times higher than that of BiOBr/TiO₂. The synergistic effect between TiO₂ and V_o-BiOBr results in enhanced light absorption and higher photoelectrocatalytic efficiency for the N₂ reduction reaction.

光催化或光电催化固氮被认为是一种非常有前途的降低能源需求的方法。在这里，通过用具有氧空位 (V _o ) 的BiOBr 纳米片修饰 TiO _{2纳米管阵列来构建 V o} -BiOBr/TiO ₂纳米复合光电极，用于光电催化固氮。氧空位促进了N ₂在催化剂表面的吸附和活化。通过将BiOBr导带上的光生电子转移到N ₂的π反键轨道上，提高了氮的路易斯碱度，更有利于质子的加成。另一方面，TiO _{2之间的异质结}和 V _o -BiOBr 促进光生载流子的分离。_{TiO 2}价带上的光生空穴行进到对电极以产生负电位的氧气，避免了NH ₃的进一步氧化。V _o -BiOBr/TiO _{2在-0.2 V时表现出25.08 μg h} ^-1  cm ^-2的高NH ₃生产率，是BiOBr/TiO ₂的3.3倍。TiO ₂和V _o -BiOBr之间的协同作用导致增强的光吸收和更高的N ₂还原反应的光电催化效率。