Electronic Modulation of the Interaction between Fe Single Atoms and WO2.72–x for Photocatalytic N2 Reduction

In the design of photocatalysts for ammonia synthesis, the construction of effective nitrogen (N2) adsorption and activation sites is critical. Herein, Fe single atoms were effectively fixed on the surfaces of WO2.72–x nanowires. Electronic interactions between single Fe atoms and WO2.72–x resulted in a d-band center shift toward the Fermi level and thus enhancement of N2 bonding with the catalyst surface. The studies of differential charge density and electron localization reveal that there is enhanced electron transfer from Fe-SA/WO2.72–x to the adsorbed N2, signifying that Fe single atoms are active centers for N2 activation. Benefiting from electronic interactions, the optimized catalyst shows a NH4+ generation rate of 186.5 μmol g–1 h–1 during photocatalytic N2 reduction.