Plasmonic semiconducting p–n junctions in a single nanoparticle for infrared light-driven efficient CO ₂ reduction

The development of photocatalysts that can efficiently harness low-energy photons, specifically infrared light, for CO₂reduction remains a formidable challenge. Plasmonic semiconductors emerge as promising candidates, addressing the inherent issues of charge recombination and energy loss encountered in single-phase semiconductors. Here, we grow a plasmonic p-Cu₇S₄/n-CdS heterojunction directly onto a single CdS nanoparticle by ion exchange. The resulting plasmonic p-Cu₇S₄/n-CdS heterojunction exhibits a highly efficient photocatalytic reduction property for converting CO₂into CO, CH₄, and C₂H₄when excited solely under near-infrared light irradiation. In a gas-solid configuration using CO₂with water vapor as the sole electron donor (no sacrificial agents), the CO production rate reaches 86.4<i>μ</i>mol g^-1h^-1, ∼63-fold that of Cu₇S₄ alone. Our work not only represents a groundbreaking advancement in the realm of infrared light-driven photocatalysts but also showcases the potential of plasmonic semiconductors for practical applications.