Plasmonic semiconducting p-n junctions in a single nanoparticle for infrared light-driven efficient CO2 reduction

The development of photocatalysts that can efficiently harness low-energy photons, specifically infrared light, for CO2 reduction 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 CO2 into CO, CH4, and C2H4 when excited solely under NIR light irradiation. In a gas–solid configuration using CO₂ with water vapor as the sole electron donor (no sacrificial agents), the CO production rate reaches 86.4 μmol g⁻¹ h⁻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.