Recent Progress on Phase Engineering of Nanomaterials

Abstract

As a key structural parameter, phase depicts the arrangement of atoms in materials. Normally, a nanomaterial exists in its thermodynamically stable crystal phase. With the development of nanotechnology, nanomaterials with unconventional crystal phases, which rarely exist in their bulk counterparts, or amorphous phase have been prepared using carefully controlled reaction conditions. Together these methods are beginning to enable phase engineering of nanomaterials (PEN), i.e. , the synthesis of nanomaterials with unconventional phases and the transformation between different phases, to obtain desired properties and functions. This Review summarizes the research progress in the field of PEN. First, we present representative strategies for the direct synthesis of unconventional phases and modulation of phase transformation in diverse kinds of nanomaterials. We cover the synthesis of nanomaterials ranging from metal nanostructures such as Au, Ag, Cu, Pd, and Ru, and their alloys; metal oxides, borides, and carbides; to transition metal dichalcogenides (TMDs) and 2D layered materials. We review synthesis and growth methods ranging from wet-chemical reduction and seed-mediated epitaxial growth to chemical vapor deposition (CVD), high pressure phase transformation, and electron and ion-beam irradiation. After that, we summarize the significant influence of phase on the various properties of unconventional-phase nanomaterials. We also discuss the potential applications of the developed unconventional-phase nanomaterials in different areas including catalysis, electrochemical energy storage (batteries and supercapacitors), solar cells, optoelectronics, and sensing. Finally, we discuss existing challenges and future research directions in PEN.

Phase Engineering of Nanomaterials: Transition Metal Dichalcogenides

“…257,391−393 TMDs used in reported twisted bilayers are still conventional phase. With the fast development of phase engineering of TMDs, 15,16,32,42,69,112,394 twisted unconventional/metastable-phase TMD bilayers or multilayers could be fabricated and used for exploration of twisted layerdependent new phenomena.…”

“…Although twisted TMD bilayers have attracted intensive research attention after the unconventional superconductivity was observed in magic-angle graphene superlattices. ,− TMDs used in reported twisted bilayers are still conventional phase. With the fast development of phase engineering of TMDs, ,,,,,, twisted unconventional/metastable-phase TMD bilayers or multilayers could be fabricated and used for exploration of twisted layer-dependent new phenomena.…”

Phase Engineering of Nanostructural Metallic Materials: Classification, Structures, and Applications

“…Nanostructural metallic materials are a pioneering research field of modern nanoscience. The advanced technologies (e.g., aberration-corrected transmission electron microscopy and three-dimensional atom probe tomography) contribute significantly to the fine phase-controlling of nanostructural metallic materials. , The sophisticated designs of phase size, phase distribution, and phase transformation are disclosed as a significant pathway to change the physicochemical properties, such as the near-theoretical strength achieved by the dual-phase glass-crystal structure, the extremely stable catalysis shown by the Turing catalyst with a specific phase configuration, and the unconventional phase transformation of nanomaterials. − This progress inspired material scientists as to the importance of phase engineering that would provide new insights and scientific implications for the development of high-performance materials. Indeed, the concept of phase in structural materials is sometimes different from nanomaterials, primarily due to differences in their scale, structural characteristics, and physical properties.…”

Ultrafast micro/nano-manufacturing of metastable materials for energy

“…Currently, the manufacturing of metastable nanomaterials encounters formidable challenges, such as limited intrinsic structures, particle agglomeration, poor activity and stability, complicated fabrication processes, and low producing efficiency, owing to the thermodynamic instability of metastable materials and the heuristic principles for preparing metastable materials. Moreover, conventional methods, such as rapid quenching, mechanical alloying, pulse laser deposition, hydrothermal synthesis and the sol-gel method, are employed for producing various metastable materials as well [ 12 ]. However, these methods encounter challenges such as limited particle size, high energy consumption, complex equipment requirements, long processing time, difficulties in achieving uniform size and distribution, and environmental concerns.…”