42
3 Synthesis of One-Dimensional Nanomaterials
Fig. 3.2 a Illustration of the mechanism of solution-based approaches. Schematic sketch of fabrication process from Ag nanowire to Ag/MnO 2 core–shell nanotube and Ag/MnO x composite nanostructure. TEM images of Ag nanowires (left), Ag/MnO 2 core–shell nanotubes produced at pH 7.00
(upper right) and Ag/MnO x composite nanosheets prepared at pH 0.76 (low right). b Schematic
illustration of the evolution processes of Ag/MnO 2 core–shell nanotubes based on the theoretical
of Kirkendall effect. c SEM images of the initial grain of the as-produced β-AlLi alloy. d–g The
formation of the Al(EtO) 3 nanowires on the β-AlLi particles; and h the SEM images of Al(EtO) 3
nanowires after the conversion reaction. i Schematic of the 1D nanowire forest formation by topdown routine. j Schematic sketch illustrating electrostatic spinning and controlled pyrolysis process.
k TEM image of the multihole Na 0.7 Fe 0.7 Mn 0.3 O 2 nanotubes with a scale bar at 200 nm. l TEM
image of the porous Co 3 O 4 nanotubes with scale at 20 nm. a, b Reprinted from Ref. Li et al. (2014),
copyright 2014, with permission from American Chemical Society. c–i Reprinted from Ref. Danni
et al. (2017), with permission from Science. j–l Reprinted from Ref. Niu et al. (2015), copyright
2015, with permission from Macmillan Publishers Limited
Moreover, microwave provides a progressive heating pattern, which is effective for
the synthesis of typical colloidal nanomaterials (Park et al. 2010). The microwaveassisted route can control the shape of a nanomaterial because it stimulates ionic
motion, molecular dipolar polarization, faster reaction kinetics, and rapid precursor
dissolution.
Tang et al. successfully synthesized vertically aligned ZnO nanorods by both
conventional heated water bath and microwave processes at 90 °C on a silicon (100)
substrate with a ZnO nanoparticle seed-layer coating (Jie et al. 2015). The optical
properties, defects, and morphologies of the ZnO nanorods fabricated by the two
processes (pH = 10.07–10.9) were revealed by photoluminescence, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The experiments demonstrated that the microwave-assisted method produced more symmetrical nanorods with fewer native defects such as zinc vacancies and oxygen interstitials. Thus, microwave-assisted synthesis was shown to be a promising approach for
fabricating 1D metal oxide nanostructures.
3 Synthesis of One-Dimensional Nanomaterials
Fig. 3.2 a Illustration of the mechanism of solution-based approaches. Schematic sketch of fabrication process from Ag nanowire to Ag/MnO 2 core–shell nanotube and Ag/MnO x composite nanostructure. TEM images of Ag nanowires (left), Ag/MnO 2 core–shell nanotubes produced at pH 7.00
(upper right) and Ag/MnO x composite nanosheets prepared at pH 0.76 (low right). b Schematic
illustration of the evolution processes of Ag/MnO 2 core–shell nanotubes based on the theoretical
of Kirkendall effect. c SEM images of the initial grain of the as-produced β-AlLi alloy. d–g The
formation of the Al(EtO) 3 nanowires on the β-AlLi particles; and h the SEM images of Al(EtO) 3
nanowires after the conversion reaction. i Schematic of the 1D nanowire forest formation by topdown routine. j Schematic sketch illustrating electrostatic spinning and controlled pyrolysis process.
k TEM image of the multihole Na 0.7 Fe 0.7 Mn 0.3 O 2 nanotubes with a scale bar at 200 nm. l TEM
image of the porous Co 3 O 4 nanotubes with scale at 20 nm. a, b Reprinted from Ref. Li et al. (2014),
copyright 2014, with permission from American Chemical Society. c–i Reprinted from Ref. Danni
et al. (2017), with permission from Science. j–l Reprinted from Ref. Niu et al. (2015), copyright
2015, with permission from Macmillan Publishers Limited
Moreover, microwave provides a progressive heating pattern, which is effective for
the synthesis of typical colloidal nanomaterials (Park et al. 2010). The microwaveassisted route can control the shape of a nanomaterial because it stimulates ionic
motion, molecular dipolar polarization, faster reaction kinetics, and rapid precursor
dissolution.
Tang et al. successfully synthesized vertically aligned ZnO nanorods by both
conventional heated water bath and microwave processes at 90 °C on a silicon (100)
substrate with a ZnO nanoparticle seed-layer coating (Jie et al. 2015). The optical
properties, defects, and morphologies of the ZnO nanorods fabricated by the two
processes (pH = 10.07–10.9) were revealed by photoluminescence, X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). The experiments demonstrated that the microwave-assisted method produced more symmetrical nanorods with fewer native defects such as zinc vacancies and oxygen interstitials. Thus, microwave-assisted synthesis was shown to be a promising approach for
fabricating 1D metal oxide nanostructures.