Hydrogen energy, known for its high energy density, environmental friendliness, and renewability, stands out as a promising alternative to fossil fuels. However, its broader application is limited by the challenge of efficient and safe storage. In this context, solid-state hydrogen storage using nanomaterials has emerged as a viable solution to the drawbacks of traditional storage methods. This comprehensive review delves into the recent advancements in nanomaterials for solid-state hydrogen storage, elucidating the fundamental principles and mechanisms, highlighting significant material systems, and exploring the strategies of surface and interface engineering alongside catalytic enhancement. We also address the primary challenges and provide future perspectives on the development of nanomaterial-based hydrogen storage technologies. Key discussions include the role of nanomaterial size effects, surface modifications, nanocomposites, and nanocatalysts in optimizing storage performance.

CeO₂ is an important rare earth (RE) oxide and has served as a typical oxygen storage material in practical applications. In the present study, the oxygen storage capacity (OSC) of CeO₂ was enhanced by doping with other rare earth ions (RE, RE = Yb, Y, Sm and La). A series of Undoped and RE–doped CeO₂ with different doping levels were synthesized using a solvothermal method following a subsequent calcination process, in which just Ce(NO₃)₃∙6H₂O, RE(NO₃)₃∙nH₂O, ethylene glycol and water were used as raw materials. Surprisingly, the Undoped CeO₂ was proved to be a porous material with a multilayered special morphology without any additional templates in this work. The lattice parameters of CeO₂ were refined by the least–squares method with highly pure NaCl as the internal standard for peak position calibrations, and the solubility limits of RE ions into CeO₂ were determined; the amounts of reducible–reoxidizable Ceⁿ⁺ ions were estimated by fitting the Ce 3d core–levels XPS spectra; the non–stoichiometric oxygen vacancy (V_O) defects of CeO₂ were analyzed qualitatively and quantitatively by O 1s XPS fitting and Raman scattering; and the OSC was quantified by the amount of H₂ consumption per gram of CeO₂ based on hydrogen temperature programmed reduction (H₂–TPR) measurements. The maximum [OSC] of CeO₂ appeared at 5 mol.% Yb–, 4 mol.% Y–, 4 mol.% Sm– and 7 mol.% La–doping with the values of 0.444, 0.387, 0.352 and 0.380 mmol H₂/g by an increase of 93.04, 68.26, 53.04 and 65.22%. Moreover, the dominant factor for promoting the OSC of RE–doped CeO₂ was analyzed.

A facile dip-coating approach was developed to fabricate visible/near-IR antireflective and superhydrophobic coatings on glass substrates from hydrophobic hexamethyldisilazane (HMDS)-modified hollow silica nanoparticles (HMDS–HSNs) and poly(methyl methacrylate) (PMMA). While the coated glass substrates showed greatly enhanced transmittance in the visible/near-IR range as compared with uncoated glass substrates, water droplets could roll easily and quickly off the coated surfaces. For the coating prepared using a suspension of 1.00 wt% PMMA and 0.50 wt% HMDS–HSNs, the water contact angle (WCA) of the coating was as high as 163° with a sliding angle (SA) of ≤1°, and the coated glass substrate showed excellent antireflection in the visible/near-IR spectral range with a maximum transmittance of 92.6%. The average transmittance of the coated glass substrate increased to 91.5% as compared to that of the uncoated glass substrate (88.2%) in the spectral range of 573–2500 nm. In particular, in the spectral range of 850–1200 nm, the coated glass substrate (ca. 91%) exhibited an increase of nearly 5% in transmittance as compared with the uncoated glass substrate (ca. 86%). Scanning electron microscopy (SEM), transmission electron microscopy (TEM) and atomic force microscopy (AFM) were used to observe the morphology and structure of the nanoparticles and the coated surfaces. The effects of PMMA and HMDS–HSN concentrations were also discussed on the basis of experimental observations.

Superhydrophobic self-cleaning antireflective coatings were fabricated on Fresnel lenses by integrating solid silica nanoparticles (SSNs) and stearic acid (STA) and 1H,1H,2H,2H-perflurooctyltriethoxysilane (POTS) co-modified hollow silica nanoparticles (SPHSNs) via spin- and spray-assembly without any high temperature pre- or post-treatment. Transmission electron microscopy (TEM) was used to observe the morphology and structure of nanoparticles. Transmission spectra were recorded using a UV-Vis-NIR spectrophotometer. Surface wettability was studied by an automatic contact angle/interface system. Condensation performance of the Fresnel lenses was studied by measuring the focal length and the powers before and after being focused. The (SSNs)₁/(SPHSNs)₂ coating turned out to simultaneously demonstrate excellent superhydrophobic self-cleaning and antireflective properties, which has a maximum transmittance of 99.0% and average transmittance of 98.5% in the wavelength range of 400–800 nm, and the condensing efficiency of the coated Fresnel lens has also been significantly improved. The surface morphology and structure of coatings were examined by scanning electron microscopy (SEM) and atomic force microscopy (AFM). The effects of surface morphology and structure on the optical and wetting properties of coatings were also discussed. The density of SPHSNs on the coating surface was considered to significantly influence both the light transmission and hydrophobicity of coated Fresnel lenses.