Dual Near‐Infrared‐Response S‐Scheme Heterojunction with Asymmetric Adsorption Sites for Enhanced Nitrogen Photoreduction

Abstract Photocatalytic nitrogen reduction reaction (PNRR) holds immense promise for sustainable ammonia (NH₃) synthesis. However, few photocatalysts can utilize NIR light that carries over 50% of the solar energy for NH₃ production with high performance. Herein, a dual NIR‐responsive S‐scheme ZnCoS_x/Fe₃S₄ heterojunction photocatalyst is designed with asymmetric adsorption sites and excellent PNRR performance. The heterojunction possesses a hollow‐on‐hollow superstructure: Fe₃S₄ nanocrystal‐modified ZnCoS_x nanocages as building blocks assemble into spindle‐shaped particles with a spindle‐like cavity. Both Fe₃S₄ and ZnCoS_x are NIR active, allowing efficient utilization of full‐spectrum light. Moreover, an S‐scheme heterojunction is constructed that promotes charge separation. In addition, the Fe/Co dual‐metal sites at the interface enable an asymmetric side‐on adsorption mode of N₂, favoring the polarization and activation of N₂ molecules. In combination with the promoted mass transfer and active site exposure of hollow superstructure, a superior PNRR performance is achieved, with a high NH₃ evolution rate of 2523.4 µmol g⁻¹ h⁻¹, an apparent quantum yield of 9.4% at 400 nm and 8% at 1000 nm, and a solar‐to‐chemical conversion efficiency of 0.32%. The work paves the way for the rational design of advanced heterojunction catalysts for PNRR.