Design of efficient Z-scheme heterojunction photocatalysts remains a pivotal challenge in photocatalytic CO₂ reduction. Herein, a three-dimensional (3D) flower-like CdIn₂S₄ nanosphere photocatalyst decorated with CdS nanoparticles (CdS/CdIn₂S₄) was successfully synthesized via a one-pot solvothermal method. The unique hierarchical architecture exposes enhanced light-harvesting interfaces and abundant reactive sites, while coupling CdS with CdIn₂S₄ constructs a direct Z-scheme heterojunction at the interface that promotes photogenerated electron migration and charge separation efficiency. The optimized CdS/CdIn₂S₄-10 catalyst achieves exceptional visible-light-driven CO₂ reduction performance with a CO production rate of 12.9 μmol·g⁻¹·h⁻¹ and 100% selectivity, representing 8-fold and 5-fold enhancements over pristine CdS and CdIn₂S₄, respectively. In-situ diffuse reflection infrared fourier transform spectra (DRIFTS) and density functional theory (DFT) calculations elucidate the mechanism for photocatalytic CO₂ reduction: the built-in electric field at the interface of the Z-scheme heterojunction drives directional electron transfer to enable spatial separation of high-redox-potential photogenerated charge carriers, with *COOH intermediate formation identified as the key step to realize the photocatalytic conversion of CO₂ to CO. This work provides fundamental insights for constructing high-efficiency Z-scheme photocatalytic systems.

The enhancement of activity and stability of noble metal-based catalysts for purification of auto-exhaust carbon particle (soot) oxidation remains a grand challenge under harsh reaction conditions. Herein, the encapsulated catalysts of platinum nanoparticles (NPs) confined in silicalite-1 (S-1) zeolite were prepared by the ligand-protected in-situ synthesis method. The Pt NPs (4 nm) are located within the intersectional channels between the straight and the sinusoidal 10-ring channels of rigid S-1 zeolite and well stabilize inside the S-1 via Pt–O–Si bonds. The Pt@S-1 catalyst (0.38 wt.% of Pt loading) exhibits excellent performance (T₅₀ = 368 °C, T₅₀ corresponds to the temperatures at which 50% of soot conversion occurs) compared with the conventional Pt/S-1 catalyst during soot oxidation. The Pt@S-1 catalyst displays high long-term catalytic stability after the hydrothermal aging at 800 °C for 10 h, and the deactivation rate of the Pt@S-1 catalyst is one-tenth that of the Pt/S-1 catalyst. In-situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and density functional theory (DFT) calculations corroborated that the encapsulated Pt NPs in Pt@S-1 catalyst display a higher d-band center than the isolated Pt NPs, which enhances bonding strength for co-adsorption of NO and O₂ molecules. The steric hindrance effect promotes the desorption of the critical intermediate of NO₂, which is the key step to the NO₂-assistant catalytic mechanism for soot oxidation. The ligand-protected in-situ confinement synthesis of metal nanoparticle catalysts not only ensures high activity and stability but also paves the way for the development of effective catalysts for soot oxidation in practical applications.