Exploring monolayer Ta4C3Tx MXene for quick ammonia detection at room temperature

Two-dimensional (2D) MXenes have emerged as promising gas sensor materials due to their abundant surface functional groups, excellent conductivity, and large surface area. In this work, we synthesized 2D Ta4C3Tx nanosheets via hydrofluoric acid (HF) etching followed by a tetramethylammonium hydroxide (TMAOH) intercalation treatment. Systematical characterization reveals the as-prepared 2D Ta4C3Tx exhibits promising monolayer morphology with abundant oxygen containing functional groups. The sensor device based on monolayer Ta4C3Tx presents a brilliant response to ammonia gas at room temperature, well surpassing those based on other previously reported MXenes. The high selectivity of Ta4C3Tx for ammonia gas was explored through first-principle calculations. This study highlights the significant potential of monolayer Ta4C3Tx for developing high-performance room-temperature ammonia gas sensors.