Microwave dielectric ceramics (MWDCs) with low dielectric constant and low dielectric loss are desired in contemporary society, where the communication frequency is developing to high frequency (sub-6G). Herein, Nd₂(Zr_1−xTi_x)₃(MoO₄)₉ (NZ_1−xT_xM, x = 0.02–0.10) ceramics were prepared through a solid-phase process. According to X-ray diffraction (XRD) patterns, the ceramics could form a pure crystal structure with the R $\overline{3}$c (167) space group. The internal parameters affecting the properties of the ceramics were calculated and analyzed by employing Clausius–Mossotti relationship, Shannon’s rule, and Phillips–van Vechten–Levine (P–V–L) theory. Furthermore, theoretical dielectric loss of the ceramics was measured and analyzed by a Fourier transform infrared (IR) radiation spectrometer. Notably, when x = 0.08 and sintered at 700 ℃, optimal microwave dielectric properties of the ceramics were obtained, including a dielectric constant (ε_r) = 10.94, Q·f = 82,525 GHz (at 9.62 GHz), and near-zero resonant frequency temperature coefficient (τ_f) = −12.99 ppm/℃. This study not only obtained an MWDC with excellent properties but also deeply analyzed the effects of Ti⁴⁺ on the microwave dielectric properties and chemical bond characteristics of Nd₂Zr₃(MoO₄)₉ (NZM), which laid a solid foundation for the development of rare-earth molybdate MWDC system.

A novel and facile method was successfully developed to fabricate nanotube (NT) and nanowire (NW) arrays through an anodic aluminum oxide (AAO) template-based Ti(OC₄H₉)₄ hydrolysis process. The wall thickness of the TiO₂ NTs can be controlled by adjusting the concentration of Ti(OC₄H₉)₄ solutions. A continuous series from thin-walled NTs to completely filled NWs were synthesized using Ti(OC₄H₉)₄ solutions of different concentrations from 0.1 to 2.0 M. The TiO₂ NTs and NWs in the AAO membrane transformed from amorphous to nanocrystalline anatase completely after annealing at 650 °C, which is higher than the phase transformation temperature of TiO₂ powder. Optical spectra of the synthesized TiO₂ NT and NW arrays/AAO composite nanostructures were characterized and showed a blue shift of the optical absorption edge with the decrease of NT wall thickness, due to the nanoscale effect and shape dependent transformation.