Development of Highly NIR-Reflective Hollow Black TiO2 from Recycled Silicon Sludge for LiDAR-Detectable Coatings in Autonomous Vehicles

초록

A LiDAR-detectable hollow black TiO2 (HBT) pigment was successfully synthesized utilizing recycled silicon sludge as a template material. The fabrication process involved coating the surface of sludge with a TiO2 layer via a sol-gel reaction using titanium(IV) isopropoxide (TTIP) as a precursor, followed by etching the template to form a hollow structure and subsequent reduction with NaBH4 to attain a black color. The resulting HBT exhibited excellent hydrophilicity, enabling uniform dispersion in varnish without the need for additional dispersing agents or surface treatments. When applied as a monolayer coating, the HBT-based paint exhibited a blackness (L*=16.7), comparable to that of commercial black coatings. In addition, HBT demonstrated a high near-infrared (NIR) reflectance of 26.6 R% at 905 nm, enabling the successful detection of autonomous vehicles by LiDAR sensors. This high reflectance is attributed to the difference in refractive indices between black TiO2 and the internal air. Conclusively, these results demonstrate the potential of HBT as a sustainable, recyclable, and LiDAR-detectable black pigment for next-generation autonomous vehicles. Key words: Black TiO2, LiDAR, Sludge, Recycle, Autonomous vehicle 사사 본 연구는 2025년도 정부(교육부)의 재원으로 한국연구재단의 지원을 받아 수행된 기초연구사업임 (RS-2022-NR070869)