Stabilizing Ti3C2T x MXene flakes in air by removing confined water

摘要: MXenes have demonstrated potential for various applications owing to their tunable surface chemistry and metallic conductivity. However, high temperatures can accelerate MXene film oxidation in air. Understanding the mechanisms of MXene oxidation at elevated temperatures, which is still limited, is critical in improving their thermal stability for high-temperature applications. Here, we demonstrate that Ti 3 C 2 T x MXene monoflakes have exceptional thermal stability at temperatures up to 600° C in air, while multiflakes readily oxidize in air at 300° C. Density functional theory calculations indicate that confined water between Ti 3 C 2 T x flakes has higher removal energy than surface water and can thus persist to higher temperatures, leading to oxidation. We demonstrate that the amount of confined water correlates with the degree of oxidation in stacked flakes. Confined water can be fully removed by vacuum …