Amorphous Fe₂CoO_x cocatalysts enable efficient photocatalytic nitrogen reduction reaction: Synergistic nitrogen...

Developing high-performance photocatalytic systems for nitrogen fixation is a crucial yet challenging for sustainable ammonia synthesis. Herein, an amorphous Fe₂CoO_x cocatalyst is successfully loaded onto Bi₂MoO₆ (BMO) to construct a highly efficient photocatalytic nitrogen reduction reaction (NRR) system. Visible-light-driven ammonia production over the optimized 1.0Fe₂CoO_x/BMO composite reaches 860.7 μmol g^-1 h^-1, about 15.4 times that of pristine BMO, outperforming most reported photocatalysts. The results of comprehensive characterizations and density functional theory calculations demonstrate that the amorphous Fe₂CoO_x cocatalyst not only rapidly captures photogenerated electrons and suppresses charge recombination, but also provides abundant Fe sites as dominant active centers that boost N₂ adsorption and activation. More importantly, the introduction of Fe₂CoO_x unlocks the previously kinetically blocked distal pathway in addition to the intrinsic alternating pathway, thereby broadening the reaction pathways and significantly accelerating the overall NRR kinetics. In addition, the universal performance enhancement capability of this amorphous cocatalyst is verified on multiple representative photocatalysts, including ZnIn₂S₄, Bi₂WO₆, TiO₂ and g-C₃N₄. This work demonstrates that engineering amorphous bimetallic oxide cocatalysts is an effective strategy for developing highly efficient photocatalytic NRR systems.