Phase engineering of nanomaterials: from fundamentals to application frontiers

Phase, which refers to the specific atomic arrangement, is one of the key parameters to determine the physicochemical properties and functions of nanomaterials. Recently, phase engineering of nanomaterials (PEN) has emerged as a promising research direction in materials science, since precise control over atomic arrangements enables the synthesis of nanomaterials with unconventional phases that are different from their thermodynamically stable counterparts, resulting in unique physicochemical properties. Therefore, PEN provides a new strategy for developing novel functional nanomaterials to enhance their performance in various applications. This review focuses on PEN strategies for preparing novel noble metals and transition metal dichalcogenides (TMDs) with unconventional phases. It provides a comprehensive summary of crucial synthetic methods, such as direct synthesis and phase transformation, demonstrates their phase-dependent properties and catalytic performance, and highlights the significant impact of phase on the functions and applications of nanomaterials. Finally, we discuss the challenges and future directions for PEN, including in-depth studies on synthetic mechanisms, effective strategies to improve the stability of unconventional-phase nanomaterials, and innovative AI-aided structural design. These efforts aim to provide theoretical and technical guidance on both fundamental research and practical applications in the field of PEN. © 2025 College of Chemistry and Molecular Engineering, Peking University. Published by Elsevier B.V.