Interfacial Chemical-Bonded MoS₂/In–Bi₂MoO₆ Heterostructure for Enhanced Photocatalytic Nitrogen-to-Ammonia Conversion

Photocatalytic nitrogen reduction reaction (pNRR) is considered an ideal NH3 synthetic technology. Although catalysts prepared for pNRR under mild conditions have been extensively developed, they still face limitations of insufficient N2 adsorption/activation and low NH3 selectivity. Herein, a MoS2/In–Bi2MOO6 heterojunction catalyst with an interfacial chemical bond was constructed by the electrostatic self-assembly method. Efficient spatial separation of photogenerated electron/hole pairs and accelerated carrier transfer dynamics were facilitated due to the formation of a Mo–S bond at the interface between MoS2 and In–Bi2MoO6. The crystal orbital Hamiltonian population (COHP) analysis further confirmed that the electrons transferred from MoS2 into the antibonding orbital of N2 to activate the adsorbed N2, favoring nitrogen-to-ammonia (N2-to-NH3) conversion. The resultant NH3/NH4+ production rate for 3% MoS2/In–Bi2MoO6 reached 90 μmol·g–1·h–1, representing a significant improvement over pure Bi2MoO6, while the production of NO3– was minimal. Introducing MoS2 as a cocatalyst effectively inhibited the oxidation of NH3/NH4+ to NO3–, achieving selective pNRR. This work provides a foundation for selective photocatalytic nitrogen fixation, offering valuable insights into the clean production of NH3.