Study on the preparation of AgCl@Ag composite particles and the polishing mechanism of single-crystal SiC under light irradiation

Fabricated a broad-spectrum responsive AgCl@Ag photocatalyst with SPRE. • AgCl@Ag exhibits 2.4-fold higher MRR than TiO 2 under visible light. • Revealed SPRE-enhanced ·OH generation and synergistic removal mechanism. To overcome the ultraviolet (UV) light limitation of conventional TiO 2 -based photocatalysis-assisted polishing, AgCl@Ag composite particles with surface plasmon resonance effect (SPRE) were prepared via a precipitation-chemical reduction method. Their morphology, phase composition, surface chemistry, and optical absorption were characterized by SEM, XRD, XPS, and UV–Vis. Photocatalytic activity and polishing performance on single-crystal SiC were systematically compared with commercial TiO 2 under both UV and visible light. The AgCl@Ag particles showed uniform size, regular morphology, no surface impurities, and broad-spectrum absorption. Under UV light, both AgCl@Ag and TiO 2 achieved >90% methyl orange degradation within 30 min, with comparable polishing performance: AgCl@Ag yielded an MRR of 86.7 nm·h −1 and a surface roughness Sa of 3.25 nm, versus 77.0 nm·h −1 and 3.28 nm for TiO 2 . Under visible light, significant differences emerged. TiO 2 degraded only 13% of methyl orange in 30 min, with an MRR of 22.8 nm·h −1 and Sa of 6.78 nm. In contrast, AgCl@Ag achieved >55% degradation, an MRR of 55.0 nm·h −1 , and Sa of 4.93 nm under the same conditions. The SPRE of AgCl@Ag promotes photogenerated charge carrier separation, enabling ·OH radical generation that synergistically forms and mechanically removes the surface oxide layer on SiC. Download: Download high-res image (250KB) Download: Download full-size image