Strain‐Tuned d‐Band Center Coupling Dual‐Plasmon Effect in CuIn Alloy for Driving CO 2 Photoreduction

ABSTRACT Photocatalysis driven by plasmon effect offers a green and sustainable method for converting CO 2 into liquid fuels. However, the limitations of traditional plasmonic catalysts result in low catalytic efficiency. Here, an indium (In) atomic layer has been developed as a new plasmonic material, while Cu is incorporated into the In lattice to form a CuIn alloy, yielding a dual‐plasmonic photocatalyst. The alloying of Cu and In induces significant lattice compression strain and shortens interatomic electron transfer distance. This electron redistribution endows the Cu‐In site pairs with an electron‐rich structure and modulates the d‐band center to optimize adsorption capacity. This dual‐plasmon effect strengthens electron–phonon coupling and optimizes the thermodynamics of surface reactions, enabling CuIn to maintain high activity and stability. This work provides a new design strategy for the development of strain‐tuned dual‐plasmon materials.