Strategic harmonization of silica shell stabilization with Pt embedding on AuNPs for efficient artificial photosynthesis

Highly efficient, stable, selective and durable photocatalysts for CO₂ reduction systems are important to address the shortages of energy sources and carbon resources and to solve the global warming problem. Here, we report Pt-AuNPs@SiO₂-mediated efficient full-spectrum photo-conversion of CO₂ to HCOOH at room temperature. Three different morphologies of AuNPs with different controlled SiO₂ shell thicknesses were prepared. Stabilization of the silica shell was achieved by embedding with PtNPs, which are an excellent co-catalyst with high selectivity for CO₂ reduction. The prepared Pt-AuNPs@SiO₂ nanocomplex showed high efficiency, with 1.79% quantum yield and 3.07% chemical yield for CO₂ photo-conversion under visible light irradiation. The results highlighted the role of SiO₂ and the embedding of Pt nanoparticles, which broadened the surface plasmon resonance band of the core AuNPs and enhanced the photoconversion efficiency. Pt-AuNPs@SiO₂ demonstrated excellent colloidal, morphological, and photocatalytic stability, with 10 reaction recycles and a shelf-life of at least six months.