Plasmonic quantum dots modulated nano-mineral toward photothermal reduction of CO₂ coupled with biomass conversion

Simultaneous conversion of CO₂ and biomass into value-added chemicals through solar-driven catalysis holds tremendous importance for fostering a sustainable circular economy. Herein, plasmonic Bi quantum dots were immobilized on phosphoric acid modified attapulgite (P-ATP) nanorod using an in-situ reduction–deposition method, and were employed for photocatalytic reduction of CO₂ coupled with oxidation of biomass-derived benzyl alcohol. Results revealed that Bi atoms successfully integrated into the basal structure of P-ATP, forming chemically coordinated Bi–O–Si bonds that served as efficient transportation channels for electrons. The incorporation of high-density monodispersed Bi quantum dots induced a surface plasmon resonance (SPR) effect, expanding the light absorption range into the near-infrared region. As a consequence, the photo-thermal transformation was significantly accelerated, leading to enhanced reaction kinetics. Notably, 50% Bi/P-ATP nanocomposite exhibited the highest plasmon-mediated photocatalytic CH₄ generation (115.7 µmol·g⁻¹·h⁻¹) and CO generation (44.9 µmol·g⁻¹·h⁻¹), along with remarkable benzaldehyde generation rate of 79.5 µmol·g⁻¹·h⁻¹ in the photo-redox coupling system under solar light irradiation. The hydrogen protons released from the oxidation of benzyl alcohol facilitated the incorporation of more hydrogen protons into CO₂ to form key CH₃O⁻ intermediates. This work demonstrates the synergistic solar-driven valorization of CO₂ and biomass using natural mineral based catalyst.