Titanium dioxide (TiO₂) has long served as both a model photocatalyst and an interfacial scaffold for photocatalytic H₂ production because of its stable oxide lattice, well-defined band structure, and tunable nanoscale morphology. In this review, sacrificial H₂ evolution denotes reduction-side H₂ generation assisted by a hole scavenger; photoreforming couples organic-substrate oxidation with H₂ generation and may derive hydrogen from water, the substrate, or both; and overall water splitting (OWS) uses water as the sole redox substrate and requires simultaneous H₂ and O₂ evolution near a 2:1 molar ratio. TiO₂-based systems now emphasize coupled control of absorption states, directional charge migration, atomic- or nanoscale reaction sites, and immobilized mass-transfer architectures. Their principal losses arise from insufficient light absorption, carrier recombination, HER/OER kinetic mismatch, H₂/O₂ back reaction, bubble retention, and gas management. This review evaluates doping and defect engineering, sensitized absorption, crystal-phase and facet regulation, heterointerfaces, cocatalysts, and nanofiber or immobilized structures through linked criteria: effective absorption, directional migration, HER/OER closure, gas desorption and recovery, long-term stability, and reaction-boundary consistency. The resulting framework uses evidence strength to interpret performance across different reaction regimes.

Inorganic aerogels with low density, high porosity, large specific surface area, and superior mechanical properties are excellent candidate materials in fields such as thermal management, energy, catalysis, and biomedical applications. A comprehensive overview of existing elastic inorganic aerogels is provided, covering their structural units, preparation methods, mechanical performances, and applications. Meanwhile, based on the constituent building blocks and microstructures, a detailed analysis of the mechanical properties and guidelines for elastic design of aerogels is presented. Concluding with a succinct summary of prospective developmental direction, this review deliberates on the challenges and potential opportunities of elastic inorganic aerogels, with the intent of providing a versatile platform for designing new types of elastic inorganic aerogels for various applications.

Energy efficient buildings require novel thermal insulators accompanied by lightweight, mechanically robust, fire resistant, and low thermal conductivity. Ceramic fibrous aerogels have emerged as promising candidates, however it’s difficult for these materials to achieve exceptional mechanical and thermal insulation performance simultaneously. Here, we demonstrate a unique semi-template method to fabricate biomimetic-architectured silica/carbon dual-fibrous aerogel with robust mechanical performance. Specifically, aerogels with honeycomb-like cellular and nanofiber/nanonet cell wall were constructed by freeze-drying the homogeneous dispersion of SiO₂ nanofibers and cellulose nanofibers co-suspensions. It is worth noting that the biomimetic structure has been perfectly inherited even subjected to high-temperature carbonization. As a result, the excellent structural stability brought by the novel structure enables the aerogel to completely recover under large compression and buckling strain of 80%, and exhibit robust fatigue resistance over 200,000 cycles. More importantly, the aerogels exhibit ultralow thermal conductivity (0.023 W·m⁻¹·K⁻¹), superior flame retardancy, together with excellent thermal insulation performance over a wide temperature ranging from −196 to 350 °C. The fabrication of such materials may provide new ideas for the development of next-generation thermal insulators for harsh conditions.

The advancement of electrocatalytic N₂ reduction reaction (NRR) toward ambient NH₃ synthesis lies in the development of more affordable electrocatalysts than noble metals. Recently, various nanostructures of transition metal compounds have been proposed as effective electrocatalysts; however, they exist in the form of loose powders, which have to be immobilized on a matrix before serving as the electrode for electrolysis. The matrix, being it carbon paper, carbon cloth or metal foam, is electrocatalytically inactive, whose introduction inevitably raises the invalid weight while sacrificing the active sites of the electrode. Herein, we report on the fabrication of a flexible ZrO₂ nanofibrous membrane as a novel, self-supported electrocatalyst. The heteroatom doping can not only endow the nanofibrous membrane with excellent flexibility, but also induce oxygen vacancies which are responsible for easier adsorption of N₂ on the ZrO₂ surface. To improve the electrocatalytic activity, a facile SILAR approach is employed to decorate it with CdS quantum dots (QDs), thereby tuning its Fermi level. To improve the conductivity, a g-C₃N₄ nanolayer is further deposited which is both conductive and active. The resulting hierarchically structured, self-supported electrocatalyst, consisting of g-C₃N₄ encapsulated ZrO₂ nanofibrous membrane decorated with CdS QDs, integrates the merits of the three components, and exhibits a remarkable synergy toward NRR. Excellent NH₃ yield of 6.32 × 10^-10 mol·s^-1·cm^-2 (-0.6 V vs. RHE) and Faradaic efficiency of 12.9% (-0.4 V vs. RHE) are attained in 0.1 M Na₂SO₄.