第161回

The family of MAX phases — with chemical formula of Mn+1AXn, where n = 1, 2, or 3, “M” is an early transition metal (Sc, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo), "A" is A group elements (Al, Si, P, S, Ga, Ge, As, In, Sn) and "X" is carbon and/or nitrogen — are a large family of layered ceramics with structural applications. Recently, MAX phases have been exfoliated into 2D single and/or multi Mn+1Xn layers by using appropriate acid solutions. The resulting 2D-Mn+1Xn transitional metal carbides and nitrides have been named as MXenes. Considering a large number of compositional possibilities of MAX phase compounds, a large number of MXenes with unprecedented properties could also be obtained in the future. Owing to their large surface area, hydrophilicity, adsorption ability, and high surface reactivity, 2D MXenes have experimentally attracted attention for many potential applications, e.g., catalysts, ion batteries, gas storage media, and sensors. Given the fast progress of MXene-based science and technology, in this presentation, I would like to update your knowledge of electronic properties and some of the possible applications of MXenes.