The controllable synthesis of nanocrystals with a desired structure and morphology is still a great challenge in the chemistry and materials fields. In this work, we report a simple solvothermal method for the controllable synthesis of sodium and cesium doped tungsten bronze nanocrystals (Na_xCs_yWO₃ (NaCWO)) with different morphologies and crystalline phases, through adjusting the amounts of H⁺ and H₂O in the reactive system. Furthermore, ethocel/NaCWO films with high transparency are also fabricated via a solution mixing method. The growth mechanisms of the NaCWO nanocrystals are investigated systematically, and structure–property relationships are also explored. Results indicate that the as-prepared two kinds of crystalline phase NaCWO nanocrystals with four morphologies can be monodispersed in toluene to form transparent nanodispersions. Among these systems, the one with rod-shaped hexagonal nanocrystals exhibits the most excellent near-infrared absorption properties, with 3.5% near-infrared transmittance at 1000 nm, and it simultaneously holds high visible light transmittance of 84% at 440 nm. Owing to the good dispersion of the nanocrystals, the ethocel/NaCWO film with an NaCWO content of 10 per hundred of ethocel resin by weight maintains the same optical performance as the nanodispersion, which is significantly important for the development of NIR absorption materials applied to energy-saving glass, solar collectors, optical filters, etc.

The pore structure of a hydrotreating catalyst plays a pivotal role in hydrodemetallization (HDM) reactions. To effectively construct a meso-macroporous catalyst, we employed a CTAB-guided in situ TEOS hydrolysis approach to prepare silica-coated γ-Al₂O₃@SiO₂ composite supports. The silica shell incorporation significantly enhances specific surface area and reduces the metal–support interactions, thereby improving the dispersion of NiMo active components and boosting the deposition of metal impurity. Hence, the NiMo/Al₂O₃@SiO₂ catalyst (2.8 wt.% NiO, 4.3 wt.% MoO₃) exhibits much higher HDM activity than that of NiMo/Al₂O₃. This is evidenced by markedly higher demetallization rate constant (1.38 h⁻¹) and turnover frequency (0.56 h⁻¹) of the NiMo/Al₂O₃@SiO₂. The NiMo/Al₂O₃@SiO₂ catalyst further demonstrates excellent recyclability during sequential HDM reactions. This superior catalytic behavior stems from the hierarchical meso-macroporous structure, which simultaneously facilitates the deposition of metal impurities and mitigates deactivation by pore blockage.

TiO₂-Al₂O₃ supports with different incorporation methods of titania were synthesized via three methods: impregnation (TA-I), co-precipitation (TA-CP), and co-precipitation–hydrothermal treatment (TA-HT). And the NiMoP catalysts prepared on the corresponding supports were evaluated for hydrodesulfurization (HDS) reactions. The results demonstrated that the Ti atoms in TA-I are attached to alumina through hydroxyl groups, while the Ti atoms in TA-CP and TA-HT can be dispersed in the alumina skeleton. Variations in the incorporation modes of TiO₂ affect the support properties, consequently influencing the nature of the active metal on the supports. The Ti atoms dispersed in the Al₂O₃ skeleton allow an increase in the basic hydroxyl groups. Meanwhile, TiO₂ in TA-CP and TA-HT can absorb hydrogen molecules and be partially reduced. Furthermore, metal species supported on the TA-CP and TA-HT are more easily reduced and better dispersed. For the NiMoP catalysts prepared with TA-CP and TA-HT, the Ti element promotes the sulfidation degree of Mo, besides shortening the average (Ni)MoS₂ slab. The catalysts prepared with TA-CP exhibited superior activity for 4,6-DMDBT hydrodesulfurization. This can be ascribed not only to the relatively high sulfidation degree of Mo and proportion of the NiMoS active phase but also to the well-dispersed (Ni)MoS₂ slabs. Moreover, the Ti⁴⁺ ions dispersed in the Al₂O₃ skeleton can be partially reduced to act as electron donors, enhancing the metallic character of the S layers in MoS₂, which facilitates the improvement of the hydrogenation desulfurization activity.