Lateral Size-Driven Wettability, Conductivity, Magnetism, and Hydrogen Storage Properties of Ti ₃ C ₂ T _<i>x</i> MXene

Tailoring the lateral size of Ti3C2Tx MXene flakes significantly impacts their physical, chemical, and mechanical properties. In this study, Ti3C2Tx MXene flakes of varying lateral sizes are synthesized, and the role of the flakes lateral size on their wettability and electrical, magnetic, and hydrogen storage properties is investigated. The large-size Ti3C2Tx MXene (MX200) exhibits a higher water contact angle of 63.5° than the smaller-size MX40 and MX100 samples due to fewer functional groups on its surface, prone to a less hydrophilic surface. The electrical conductivity of MX200 is higher (∼730 S/m) than the smaller-size samples, attributed to lesser interflake resistance and faster electron transport. In contrast, the small-size MX40 sample shows higher magnetization (2.7 × 10–3 emu/g) at lower temperatures and 2000 Oe and forms the hysteresis with the highest saturation magnetization (4.0 × 10–3 emu/g) at 300 K and an applied field of 9000 Oe. Further, the lateral size of the flakes significantly influences the hydrogen storage capacity. MX40 shows a higher hydrogen storage capacity of 5.26 wt % at 173 K, and above this temperature, the largest MXenes demonstrate better hydrogen storage performance. Therefore, optimization of lateral size is a critical design parameter for maximizing the performance of Ti3C2Tx MXene across diverse fields, including electronics, spintronics, energy storage, and advanced composites.