B. Anasori
Purdue University,
United States
Keywords: 2D materials, Mxene
Summary:
The family of two-dimensional (2D) transition metal carbides and nitrides, known as MXenes, is one of the largest 2D material families, with over eighty synthesized compositions. MXenes are primarily synthesized through the top-down selective etching of their precursor MAX phases. Consequently, the design of new MXene compositions depends on the synthesis of novel layered carbide MAX phases. In 2021, a new research area emerged within MAX/MXenes: high-entropy MAX and MXene phases, making MXenes one of the first 2D materials to enter the field of high-entropy research. In these phases, four or more transition metals are combined as solid solutions within the 2D atomic planes. In this talk, I will present a systematic study of about 40 multi-transition-metal MAX/MXene phases, incorporating different numbers and types of transition metals in the M layers. Specifically, we study MAX and MXene phases with 2, 4, 5, 6, 7, 8, and 9 transition metals from groups 4 to 6 of the periodic table, including Ti, Zr, Hf, Nb, V, Ta, Cr, Mo, and W. The goal is to understand the influence of entropy versus enthalpy on the formation of these phases. By combining various elements and analyzing the atomic layer-by-layer composition of the 2D carbide layers, we determine how many transition metals are required to form fully disordered high-entropy layered carbides. Additionally, we demonstrate how to synthesize novel high-entropy MXenes from these phases and explore some of their properties.