Fig 1

Schematic illustration of nanomaterials with different crystal phases."

Fig 2

(a) Schematic illustration of the synthesis, TEM image, and structure models of 2H-Au SSs on GO, adapted with permission from Ref. [13]. Copyright © 2011, Springer Nature; (b) Schematic illustration of the synthesis of Au NWs containing 2H phase on GO, and the TEM, high-resolution (HRTEM) images and selected area electron diffraction (SAED) pattern of Au NWs, adapted with permission from Ref. [14]. Copyright © 2012, John Wiley and Sons."

Fig 3

(a) Structural model and high-resolution High-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) image of 4H-Au nanoribbon, adapted with permission from Ref. [20]. Copyright © 2015, Springer Nature; (b) Schematic illustration of the synthesis of 4H/fcc Au nanorod and the corresponding TEM image, adapted with permission from Ref. [21]. Copyright © 2017, John Wiley and Sons; (c) Structural model and high-resolution HAADF-STEM image of fcc/2H/fcc Au nanorod, adapted with permission from Ref. [23]. Copyright © 2020, Springer Nature."

Fig 4

Schematic illustrations of the epitaxial growth of secondary metals on different metal seeds with unconventional phases. (a) Epitaxial growth of Pd on fcc/2H/fcc Au nanorod, adapted with permission from Ref. [38]. Copyright © 2022, American Chemical Society; (b) Epitaxial growth of Ru on 4H/fcc Au nanorod, adapted with permission from Ref. [40]. Copyright © 2018, Springer Nature; (c) Epitaxial growth of Rh on 2H/fcc Au nanosheets, adapted with permission from Ref. [22]. Copyright © 2021, American Chemical Society; (d) Epitaxial growth of NiRh on 2H-Pd nanoparticles, adapted with permission from Ref. [43]. Copyright © 2024, American Chemical Society."

Fig 5

(a) Phase transformation of 2H-Au SS to fcc Au nanosheet, adapted with permission from Ref. [3]. Copyright © 2020, Springer Nature; (b) Phase transformation of 4H-Au nanoribbon to fcc Au nanoribbon, adapted with permission from Ref. [20]. Copyright © 2015, Springer Nature; (c) Phase transformation of amorphous Pd to fcc- and 2H-Pd under different experimental conditions, adapted with permission from Ref. [26]. Copyright © 2020, American Chemical Society."

Fig 6

(a) Transformation of 4H-Au nanorod to fcc-Au nanorod by ligand exchange, adapted with permission from Ref. [20]. Copyright © 2015, Springer Nature; (b) Transformation of 2H-Au SS to 2H/fcc Au nanosheet by secondary growth, adapted with permission from Ref. [56]. Copyright © 2011, John Wiley and Sons; (c) Partial transformation of 4H-Au nanorod to fcc-Au by electron beam irradiation when the 4H-Au nanorod contacts the fcc-Au nanoparticle with size of around 12 nm, adapted with permission from Ref. [58]. Copyright © 2019, John Wiley and Sons."

Table 1

Summary of different PEN strategies for noble metal nanomaterials."

Fig 7

(a) SEM image, high-resolution HAADF-STEM image (inset: FFT pattern), and structural model of 1T′-MoS2, adapted with permission from Ref. [74]. Copyright © 2018, Springer Nature; (b) SEM image (inset: optical image), high-resolution HAADF-STEM image, and structural model of 1T′-WS2, adapted with permission from Ref. [75]. Copyright © 2021, Springer Nature."

Fig 8

(a) Transformation of 2H-TMD crystals to 1T-TMD nanodots by chemical lithium intercalation, adapted with permission from Ref. [92]. Copyright © 2018, John Wiley and Sons; (b) Phase transformation of TMDs from 2H to mixed phases by electrochemical lithium intercalation, adapted with permission from Ref. [95]. Copyright © 2011, John Wiley and Sons; (c) Transformation of 1T′-TMD to 2H-TMD by laser irradiation, adapted with permission from Ref. [74]. Copyright © 2018, Springer Nature."

Fig 9

(a) LSV curves showing HER catalyzed by 2H/fcc Au nanosheets and derived Type C Rh-Au heterostructures, adapted with permission from Ref. [22]. Copyright © 2021, American Chemical Society; (b) LSV curves showing HER catalyzed by 4H/fcc Au@PdAg nanoribbons, adapted with permission from Ref. [35]. Copyright © 2016, American Chemical Society; (c) LSV curves showing HER catalyzed by 4H/fcc Au nanowires and derived 4H/fcc Au-Ru-2 nanowires, adapted with permission from Ref. [40]. Copyright © 2018, Springer Nature; (d) LSV curves showing ORR catalyzed by 2H-Pd based alloys, adapted with permission from Ref. [44]. Copyright © 2021, American Chemical Society; (e) CO Faradaic efficiencies (FEs) under different potentials from CO2RR catalyzed by fcc-2H-fcc Au nanorods, adapted with permission from Ref. [23]. Copyright © 2020, Springer Nature; (f) CV curves showing AOR catalyzed by fcc-2H-fcc Au nanorods and derived fcc-2H-fcc Au@Pd nanorods, adapted with permission from Ref. [38]. Copyright © 2022, American Chemical Society."