Safe storage and utilisation of hydrogen is an ongoing area of research, showing potential to enable hydrogen becoming an effective fuel, substituting current carbon-based sources. Hydrogen storage is associated with a high energy cost due to its low density and boiling point, which drives a high price. Clathrates (gas hydrates) are water-based (ice-like) structures incorporating small non-polar compounds such as H₂ in cages formed by hydrogen bonded water molecules. Since only water is required to construct the cages, clathrates have been identified as a potential solution for safe storage of hydrogen. In bulk, pure hydrogen clathrate (H₂O-H₂) only forms in harsh conditions, but confined in nanospaces the properties of water are altered and hydrogen storage at mild pressure and temperature could become possible. Here, specifically a hydrophobic mesoporous silica is proposed as a host material, providing a suitable nano-confinement for ice-like clathrate hydrate. The hybrid silica material shows an important decrease of the pressure required for clathrate formation (approx. 20%) compared to the pure H₂O-H₂ system. In-situ inelastic neutron scattering (INS) and neutron diffraction (ND) provided unique insights into the interaction of hydrogen with the complex surface of the hybrid material and demonstrated the stability of nano-confined hydrogen clathrate hydrate.

Electron tomography has become a commonly used tool to investigate the three-dimensional (3D) structure of nanomaterials, including colloidal nanoparticle assemblies. However, electron microscopy is typically done under high-vacuum conditions, requiring sample preparation for assemblies obtained by wet colloid chemistry methods. This involves solvent evaporation and deposition on a solid support, which consistently alters the nanoparticle organization. Here, we suggest using electron tomography to study nanoparticle assemblies in their original colloidal liquid environment. To address the challenges related to electron tomography in liquid, we devise a method that combines fast data acquisition in a commercial liquid-cell with a dedicated alignment and reconstruction workflow. We present the advantages of this methodology in accurately characterizing two different systems. 3D reconstructions of assemblies comprising polystyrene-capped Au nanoparticles encapsulated in polymeric shells reveal less compact and more distorted configurations for experiments performed in a liquid medium compared to their dried counterparts. A similar expansion can be observed in quantitative analysis of the surface-to-surface distances of self-assembled Au nanorods in water rather than in a vacuum, in agreement with bulk measurements. This study, therefore, emphasizes the importance of developing high-resolution characterization tools that preserve the native environment of colloidal nanostructures.

Metal halide perovskite (MHP) quantum dots (QDs) offer immense potential for several areas of photonics research due to their easy and low‐cost fabrication and excellent optoelectronic properties. However, practical applications of MHP QDs are limited by their poor stability and, in particular, their tendency to aggregate. Here, we develop a two‐step double‐solvent strategy to grow and confine CsPbBr₃ QDs within the three‐dimensional (3D) cavities of a mesoporous SBA‐16 silica scaffold (CsPbBr₃@SBA‐16). Strong confinement and separation of the MHP QDs lead to a relatively uniform size distribution, narrow luminescence, and good ambient stability over 2 months. In addition, the CsPbBr₃@SBA‐16 presents a high activity and stability for visible‐light‐driven photocatalytic toluene C(sp³)–H bond activation to produce benzaldehyde with ∼730 µmol g⁻¹ h⁻¹ yield rate and near‐unity selectivity. Similarly, the structural stability of CsPbBr₃@SBA‐16 QDs is superior to that of both pure CsPbBr₃ QDs and those confined in MCM‐41 with 1D channels.

Rhodium-platinum core-shell nanoparticles on a carbon support (Rh@Pt/C NPs) are promising candidates as anode catalysts for polymer electrolyte membrane fuel cells. However, their electrochemical stability needs to be further explored for successful application in commercial fuel cells. Here we employ identical location scanning transmission electron microscopy to track the morphological and compositional changes of Rh@Pt/C NPs during potential cycling (10 000 cycles, 0.06-0.8 V_RHE, 0.5 H₂SO₄) down to the atomic level, which are then used for understanding the current evolution occurring during the potential cycles. Our results reveal a high stability of the Rh@Pt/C system and point toward particle detachment from the carbon support as the main degradation mechanism.