Fluorine‐free synthesis of ultra‐thin, high aspect ratio <scp>Ti₃C₂T_x MXene</scp> nanosheets for high‐efficiency ultraviolet‐shielding applications

Abstract MXenes, two‐dimensional transition metal carbides and nitrides, show great potential in various applications. However, traditional synthesis methods often involve toxic fluorine‐containing etchants, limiting large‐scale production. This study introduces a novel, environmentally friendly approach for synthesizing Ti 3 C 2 T x MXene nanosheets using stone grinding‐assisted exfoliation and mild alkaline etching at 80°C. The synthesized MXene nanosheets exhibited high aspect ratios with transverse dimensions mostly on the micrometer scale and a thickness of approximately 3 nm, corresponding to one to two layers of Ti 3 C 2 . MXene/polyvinyl alcohol (PVA) composite membranes were fabricated to demonstrate practical applications. The composite membrane containing 1 wt% MXene achieved a 99.9% UV shielding rate while maintaining 67% visible light transmittance. Furthermore, it significantly enhanced PLA's UV resistance, with protected samples retaining 98.1% tensile strength after 48 hours of UV exposure, compared with 47.8% for unprotected PLA. This fluorine‐free synthesis method addresses environmental concerns and enables large‐scale MXene production for advanced UV protection applications. Highlights Ti 3 C 2 T x MXene is made via stone grinding and alkaline etching. MXene nanosheets are produced in the micron range and are 1–2 layers thick. The fluorine‐free synthesis enables green, large‐scale production of MXene. MXene/PVA films show 99.99% UV shielding with 67% visible light transmittance. MXene/PVA coating improves PLA's UV resistance, keeping 98.1% of tensile strength.