Hollow TiO_2–X porous microspheres consisted of numerous well-crystalline nanocrystals with superior structural integrity and robust hollow interior were synthesized by a facile sol-gel template-assisted approach and two-step carbonprotected calcination method, together with hydrogenation treatment. They exhibit a uniform diameter of ~470 nm with a thin porous wall shell of ~50 nm in thickness. The Brunauer-Emmett-Teller (BET) surface area and pore volume are ~19 m²/g and 0.07 cm³/g, respectively. These hollow TiO_2–X porous microspheres demonstrated excellent lithium storage performance with stable capacity retention for over 300 cycles (a high capacity of 151 mAh/g can be obtained up to 300 cycles at 1 C, retaining 81.6% of the initial capacity of 185 mAh/g) and enhanced rate capability even up to 10 C (222, 192, 121, and 92.1 mAh/g at current rates of 0.5, 1, 5, and 10 C, respectively). The intrinsic increased conductivity of the hydrogenated TiO₂ microspheres and their robust hollow structure beneficial for lithium ion-electron diffusion and mitigating the structural strain synergistically contribute to the remarkable improvements in their cycling stability and rate performance.

The rational design and precise synthesis of multifunctional hybrid nanostructures with a tailored active core and a large, dendritic, modified mesoporous structured shell can promote catalysis, energy storage, and biological applications. Here, an oil-water biphase stratification coating strategy has been developed to prepare monodisperse magnetic dendritic mesoporous silica core-shell structured nanospheres. These sophisticated Fe₃O₄@SiO₂@dendritic-mSiO₂ nanospheres feature large dendritic open pores (2.7 and 10.3 nm). Significantly, the silica shells can be converted into dendritic mesoporous aluminosilicate frameworks with unchanged porosity, a Si/Al molar ratio of 14, and remarkably strong acidic sites, through a post-synthesis approach. In addition, the resultant magnetic dendritic mesoporous aluminosilicate nanospheres exhibit outstanding properties and promising application in phosphate removal from wastewater.

A facile one-pot method has been developed to synthesize uniform gold@mesoporous silica nanospheres (Au@MSNs), which have a well-defined core–shell structure with ordered mesoporous silica as a shell. The resulting Au@MSNs have a high surface area (~521 m²/g) and uniform pore size (~2.5 nm) for the mesoporous silica shell. The diameter of the gold core can be regulated by adjusting the amount of HAuCl₄. The catalytic performance of the Au@MSNs was investigated using the reduction of 4-nitrophenol as a model reaction. The mesopores of the silica shells provide direct access for the reactant molecules to diffuse and subsequently interact with the gold cores. In addition, the Au@MSNs display the great advantage of sintering-resistance to 950 ℃ because the mesoporous silica shells inhibit aggregation or deformation of the gold cores. The high thermal stability enables the Au@MSNs to be employed in high-temperature catalytic reactions.

Porous carbon nitride (CN) spheres with partially crystalline frameworks have been successfully synthesized via a nanocasting approach by using spherical mesoporous cellular silica foams (MCFs) as a hard template, and ethylenediamine and carbon tetrachloride as precursors. The resulting spherical CN materials have uniform diameters of ca. 4 μm, hierarchical three-dimensional (3-D) mesostructures with small and large mesopores with pore diameters centered at ca. 4.0 and 43 nm, respectively, a relatively high BET surface area of ~550 m²/g, and a pore volume of 0.90 cm³/g. High-resolution transmission electron microscope (HRTEM) images, wide-angle X-ray diffraction (XRD) patterns, and Raman spectra demonstrate that the porous CN material has a partly graphitized structure. In addition, elemental analyses, X-ray photoelectron spectra (XPS), Fourier transform infrared spectra (FT-IR), and CO₂ temperature-programmed desorption (CO₂-TPD) show that the material has a high nitrogen content (17.8 wt%) with nitrogen-containing groups and abundant basic sites. The hierarchical porous CN spheres have excellent CO₂ capture properties with a capacity of 2.90 mmol/g at 25 ℃ and 0.97 mmol/g at 75 ℃, superior to those of the pure carbon materials with analogous mesostructures. This can be mainly attributed to the abundant nitrogen-containing basic groups, hierarchical mesostructure, relatively high BET surface area and stable framework. Furthermore, the presence of a large number of micropores and small mesopores also enhance the CO₂ capture performance, owing to the capillary condensation effect.

We describe a nanocrystal self-assembly method for the preparation of rare earth fluoride nanotube (ReF-NT) arrays and magnetite-doped rare earth fluoride nanotubes (Fe₃O₄–ReF-NTs) by using porous anodic aluminum oxide (AAO) as a hard template. The ReF-NTs can be simply prepared by the impregnation of α-NaYF₄ nanocrystals doped with Yb and Er into the channels of the porous AAO and show a highly ordered nanotube array and excellent upconversion (UC) fluorescence properties. Similarly, the Fe₃O₄–ReF-NTs are obtained by the self-assembly of a mixture of Fe₃O₄ and Yb/Er doped α-NaYF₄ nanocrystals in the AAO pore channels and have a uniform dispersion of magnetite nanocrystals on the rare earth fluoride tube matrix and possess multifunctional magnetic/UC properties. The diameter of these nanotubes can be varied from 60 nm to several micrometers depending on the pore size of the AAO template. The wall thickness can be increased from 10 to 35 nm by increasing the concentration of nanocrystals from 0.02 to 0.4 mmol/L, while the morphology of the nanotubes can be varied from small isolated domain structures to percolating domains and eventually to compact domains. A template-directed formation mechanism is proposed and the quantitative predictions of the model for such self-assembled nanocrystal spreading processes are demonstrated. Strong UC fluorescent emissions are realized for the nanotube arrays and multifunctional nanotubes with UC excitation in the near-infrared (NIR) region. A strong magnetic response of the multifunctional nanotubes is observed, which facilitates their easy separation from solution by magnetic decantation using a permanent magnet.

A simple strategy for the synthesis of macro-mesoporous carbonaceous monolith materials has been demonstrated through an organic-organic self-assembly at the interface of an organic scaffold such as polyurethane (PU) foam. Hierarchically porous carbonaceous monoliths with cubic (Im3m) or hexagonal (p6mm) mesostructure were prepared through evaporation induced self-assembly of the mesostructure on the three-dimensional (3-D) interconnecting struts of the PU foam scaffold. The preparation was carried out by using phenol/formaldehyde resol as a carbon precursor, triblock copolymer F127 as a template for the mesostructure and PU foam as a sacrificial monolithic scaffold. Their hierarchical pore system was macroscopically fabricated with cable-like mesostructured carbonaceous struts. The carbonaceous monoliths exhibit macropores of diameter 100–450 μm, adjustable uniform mesopores (3.8–7.5 nm), high surface areas (200–870 m²/g), and large pore volumes (0.17–0.58) cm³/g. Compared with the corresponding evaporation induced self-assembly (EISA) process on a planar substrate, this facile process is a time-saving, labor-saving, space-saving, and highly efficient pathway for mass production of ordered mesoporous materials.