2025/09/14 by Xudong Wang, Wang, Xudong, Qian Fang +7
Engineering · Materials Science · #FOS: Physical sciences #Graphene and Nanomaterials Applications #Graphene research and applications #MXene and MAX Phase Materials #Materials Science (cond-mat.mtrl-sci)
paper · pdf · doi:10.48550/arxiv.2509.11380
openalex publication_date 2025/09/14 · openalex created_date 2025/10/12 · openalex updated_date 2026/07/28
Silicon-based MAX phases are a promising class of layered ceramics with superior thermal and chemical stability. However, their synthesis remains challenging due to inherent thermodynamic instability at high temperatures. Herein, we develop a general top-down strategy to synthesize a broad family of Si-substituted MAX phases (M = Ti, V, Nb, Ta, Cr; X = C, N) by reacting Al-based MAX precursors with SiCl4 vapor. This approach not only circumvents traditional high-temperature limitations but also enables precise A-site defect engineering, resulting in phases with controlled vacancy concentrations (e.g., Nb2Si3/4C and Nb2Si1/2C). Furthermore, we introduce a redox potential-based model that rationalizes the reaction pathway. Using Tin+1AlXn etched with SiCl4 as an example, the process simultaneously forms Cl-terminated MXene (Mn+1XnCl2) and amorphous nano-Si, enabling the one-step synthesis of Si-coated MXene composites. This methodology provides new avenues for designing advanced MAX phases and MXene-based hybrids with tailored functionalities for applications in energy storage and catalysis.