Strategy of constructing D-A structure and accurate active sites over graphitic carbon nitride nanowires for high efficient photocatalytic nitrogen fixation.

Fe(III)-0.5-AP-CN photocatalysts synthesized based on a donor–acceptor structure can significantly enhance the yield of N 2 reduction to NH 3. [Display omitted] • Donor-acceptor (D-A) polymeric carbon nitride constructed by covalent binding of phenanthroline units. • Intermolecular charge transfer in the presence of D-A structure promotes the rapid migration of photogenerated carriers. • Phenanthroline units in the D-A structure are coordinated with Fe3+ ions to form special nanowire morphologies. • D-A type Fe(III)-0.5-AP-CN photocatalytic synthesis of ammonia with yields up to 825.3 μmol g−1 h−1. Constructing photocatalysts for the stable and efficient production of NH 3 is of excellent research significance and challenging. In this paper, the electron acceptor 5-amino-1,10-phenanthroline (AP) is introduced into the electron-donor graphitic carbon nitride (CN) framework by a simple heated copolymerization method to construct a donor–acceptor (D-A) structure. Subsequently, the phenanthroline unit is coordinated with transition metal Fe3+ ions to obtain the photocatalyst Fe(III)-0.5-AP-CN with better nitrogen fixation performance, and the average NH 3 yield can reach 825.3 μmol g−1 h−1. Comprehensive experimental results and theoretical calculations show that the presence of the D-A structure can induce intramolecular charge transfer, effectively separating photogenerated electrons and holes. The Fe active sites can improve the chemisorption energy for N 2 , enhance the N -Fe bonding, and better activate the N 2 molecule. Therefore, the synergistic effect between the construction of the D-A structure and the stably dispersed Fe active sites can enable CN to achieve high-performance N 2 reduction to produce NH 3. [ABSTRACT FROM AUTHOR]