Using bismuth oxide (Bi₂O₃) as the matrix and employing a doping modification strategy to introduce the rare-earth element La, this study prepared La/Bi₂O₃ visible-light-responsive photocatalysts with different doping ratios. The research systematically investigated the regulation mechanisms of La doping on the material’s phase structure, microstructure, band structure characteristics, and visible-light photocatalytic performance. The results indicate that an appropriate amount of La³⁺ equivalently substitutes Bi³⁺ in the lattice, inducing the complete transformation of pure α-Bi₂O₃ into the tetragonal β-Bi₂O₃ phase while maintaining the integrity of the crystal framework. Meanwhile, the modulation of the local electronic structure caused by La³⁺ substitution effectively narrows the bandgap width and broadens the visible-light response range; it also acts as an electron trap to significantly suppress the recombination of photo-generated electron–hole pairs, thereby enhancing charge transport efficiency. Visible-light catalytic degradation experiments confirmed that 4% La/Bi₂O₃ exhibits the optimal degradation kinetics for RhB, achieving a 72.88% degradation rate of Rhodamine B within 60 min of visible-light irradiation. The first-order reaction rate constant was 23 times that of pure Bi₂O₃, and the material demonstrated good stability under repeated cycles. Radical trapping experiments indicated that the order of contribution of active species was ·O₂⁻ > h⁺ > ·OH, with the superoxide radical (·O₂⁻) being the dominant active species. This study confirms that appropriate lattice doping with La can synergistically optimize the structure and optoelectronic properties of Bi₂O₃, providing experimental evidence and theoretical references for the rational design of highly efficient and stable visible-light-responsive Bi₂O₃-based photocatalytic materials.

The chemical mechanical polishing (CMP) has been widely used for surface modification of critical materials and components and provided global planarization of topography with a low post-planarization slope high quality and efficiency. The colloidal silica slurries play an important role in the finishing processes of optical components. Monodisperse mesoporous silica nanospheres were synthesized with different surfactant by Stöber method. Their architectural features and texture parameters were characterized by XRD, FTIR, N2 adsorption–desorption isotherms, SEM, XPS, and TGA techniques. The spherical SiO2 products presented with the controllable 50-150 nm particle size and distribution. The AFM micrographs reveal that flat and smooth surfaces without distinct scratches residual particles are achieved by using the as-obtained composite particles as abrasives[The particle size of SiO2 slurry plays a critical role in the chemical-mechanical polishing process.