Ti2Au2C and Ti3Au2C2 formed by solid state reaction of gold with Ti2AlC and Ti3AlC2

Abstract

Incorporation of layers of noble metals in non-van der Waals layered materials may be used to form novel layered compounds. Recently, we demonstrated a high-temperature-induced exchange process of Au with Si in the layered phase Ti₃SiC₂, resulting in the formation of Ti₃AuC₂ and Ti₃Au₂C₂. Here, we generalize this technique showing that Au/Ti₂AlC and Au/Ti₃AlC₂ undergo an exchange reaction at 650 °C to form Ti₂Au₂C and Ti₃Au₂C₂ and determine their structures by electron microscopy, X-ray diffraction, and ab initio calculations. These results imply that noble-metal-containing layered phases should be possible to synthesize in many systems. The metal to be introduced should be inert to the transition-metal carbide layers, and exhibit negative heat of mixing with the initial A element in a liquid phase or two-phase liquid/solid region at the annealing temperature.