Ti3AlC2 MAX phase conversion to a novel 2D titanium carbo-oxide by an eco-friendly and low-cost method: highly selective gas sensing and supercapacitor evaluations

Abstract

Energy shortage and environmental pollution issues are among the biggest challenges of this century. Therefore, research into innovative new materials to overcome such issues is urgently required. In this context, this study reports the one-pot synthesis of a novel 2D titanium carbo-oxide layered structure using a simple and eco-friendly method. Then, its potential applications as a gas sensor and supercapacitor were evaluated for the first time. The 2D titanium carbo-oxide layered structure was prepared via a solvothermal method by exfoliation of the Ti₃AlC₂ MAX phase with tetramethylammonium hydroxide. X-ray diffraction, Raman spectroscopy, scanning electron microscopy, and X-ray photoelectron spectroscopy characterizations demonstrated that pure 2D titanium carbo-oxide flakes with a layered structure were successfully obtained. The synthesized nanomaterial showed a very good sensing response and high selectivity towards methanol at room temperature against ethanol and other volatile organic compounds. The investigation of its supercapacitor performance in three different aqueous electrolytes revealed that this 2D nanomaterial had a high potential window of 1.8 V in Na₂SO₄, high specific capacitance of 161 F g⁻¹ in H₂SO₄, and 87.1% capacitance retention after 2500 cycles in KOH. The probably reduced interlayer spacing can explain the underlying mechanism of the sensor and its electrochemical capacitance.