Lithium-sulfur (Li-S) battery has attracted extensive attention because of its ultrahigh theoretical energy density and low cost. However, its commercialization is seriously hampered by its short cycling life, mainly due to the shuttle of soluble lithium polysulfides (LiPSs) and poor rate capability due to sluggish reaction kinetics. Although significant efforts have been devoted to solving the problems, it is still challenging to simultaneously address all the issues. Herein, titanium nitride hollow multishelled structure (TiN HoMS) sphere is designed as a multi-functional catalytic host for sulfur cathode. TiN, with good conductivity, can effectively catalyze the redox conversion of S and LiPSs, while its surficial oxidation passivation layer can strongly anchor LiPSs. Besides, HoMS enables TiN nanoparticle subunits to expose abundant active sites for anchoring and promoting conversion of LiPSs, while the multiple shells provide physical barriers to restrict the shuttle effect. In addition, HoMS can buffer the volume expansion of sulfur and shorten the charge transport pathway. As a result, the sulfur cathode based on triple-shelled TiN HoMS exhibits an initial specific capacity of 1016 mAh·g⁻¹ at a high sulfur loading of 2.8 mg·cm⁻² and maintains 823 mAh·g⁻¹ after 100 cycles. Moreover, it shows a four times higher specific capacity than the one without TiN host at 2 C.

Solar thermal interfacial water evaporation is proposed as a promising route to address freshwater scarcity, which can reduce energy consumption and have unlimited application scenarios. The large semiconductor family with controllable bandgap and good chemo-physical stability are considered as good candidates for photo-evaporation. However, the evaporation rate is not satisfactory because the rational control of nano/micro structure and composition is still in its infancy stage. Herein, by systemically analyzing the photo-thermal evaporation processes, we applied the hollow multishelled structure (HoMS) into this application. Benefiting from the multishelled and hierarchical porous structure, the light absorption, thermal regulation, and water transport are simultaneously optimized, resulting in a water evaporation rate of 3.2 kg·m⁻²·h⁻¹, which is among the best performance in solar-vapour generation. The collected water from different water resources meets the World Health Organization standard for drinkable water. Interestingly, by using the CuO/Cu₂O system, reactive oxygen species were generated for water disinfection, showing a new route for efficient solar-vapour generation and a green way to obtain safe drinking water.

Hollow structures have demonstrated great potential in drug delivery owing to their privileged structure, such as high surface- to-volume ratio, low density, large cavities, and hierarchical pores. In this review, we provide a comprehensive overview of hollow structured materials applied in targeting recognition, smart response, and drug release, and we have addressed the possible chemical factors and reactions in these three processes. The advantages of hollow nanostructures are summarized as follows: hollow cavity contributes to large loading capacity; a tailored structure helps controllable drug release; variable compounds adapt to flexible application; surface modification facilitates smart responsive release. Especially, because the multiple physical barriers and chemical interactions can be induced by multishells, hollow multishelled structure is considered as a promising material with unique loading and releasing properties. Finally, we conclude this review with some perspectives on the future research and development of the hollow structures as drug carriers.

There remains a pressing challenge in the fabrication of superior photocatalysts for light-driven water oxidation. Here, we designed and fabricated heterostructured TiO₂/Fe₂TiO₅ hollow microspheres with single-, double-, closed-double-, triple-, and core-shell structures and different Fe/Ti molar ratios using a facile sequential templating approach. The closed-double-shelled TiO₂/Fe₂TiO₅ hollow microspheres with 35% Fe exhibited the highest oxygen evolution reaction rate up to 375 μmol·g^-1·h^-1 and good stability for 5 h. The high performance can be attributed to the closed-double shell, which had more reactive sites and greater light-harvesting ability, self-supported thin shells with short charge-transfer paths, and a favorable staggered band alignment between the TiO₂ and Fe₂TiO₅.