We apply a silica pillaring method to create a porous Mo₂TiC₂ MXene with nanoengineered interlayer distances, significantly improving performance in Li and Na-ion batteries. The charge storage mechanism is studied experimentally for the first time.

Here we report direct physical evidence that confinement of molecular hydrogen (H₂) in an optimized nanoporous carbon results in accumulation of hydrogen with characteristics commensurate with solid H₂ at temperatures up to 67 K above the liquid–vapor critical temperature of bulk H₂. This extreme densification is attributed to confinement of H₂ molecules in the optimally sized micropores, and occurs at pressures as low as 0.02 MPa. The quantities of contained, solid-like H₂ increased with pressure and were directly evaluated using in situ inelastic neutron scattering and confirmed by analysis of gas sorption isotherms. The demonstration of the existence of solid-like H₂ challenges the existing assumption that supercritical hydrogen confined in nanopores has an upper limit of liquid H₂ density. Thus, this insight offers opportunities for the development of more accurate models for the evaluation and design of nanoporous materials for high capacity adsorptive hydrogen storage.

MXenes are a recently discovered class of two-dimensional materials that have shown great potential as electrodes in electrochemical energy storage devices. Despite their promise in this area, MXenes can still suffer limitations in the form of restricted ion accessibility between the closely spaced multistacked MXene layers, causing low capacities and poor cycle life. Pillaring, a strategy where a secondary species is inserted between layers, has been used to increase interlayer spacings in clays with great success, but has had limited application in MXenes. We report a new amine-assisted pillaring methodology that successfully intercalates silica-based pillars between Ti₃C₂ layers. Using this technique, the interlayer spacing can be controlled with the choice of amine and calcination temperature, up to a maximum of 3.2 nm, the largest interlayer spacing reported for an MXene. Another effect of the pillaring is a dramatic increase in surface area, achieving BET surface areas of 235 m² g^-1, a sixty-fold increase over the unpillared material and the highest reported for MXenes using an intercalation-based method. The intercalation mechanism was revealed by different characterisation techniques, allowing the surface chemistry to be optimised for the pillaring process. The porous MXene was tested for Na-ion battery applications, and showed superior capacity, rate capability and remarkable stability compared with non-pillared materials, retaining 98.5% capacity between the 50th and 100th cycles. These results demonstrate the applicability and promise of pillaring techniques applied to MXenes, providing a new approach to optimising their properties for a range of applications. Porous MXenes are very promising materials for a range of applications including energy storage, conversion, catalysis and gas separations.

The rising level of atmospheric carbon dioxide (CO₂) is a major driver of climate change, highlighting the need to develop carbon capture and storage (CCS) technologies quickly. This paper offers a comparative review of three main groups of porous adsorbent materials—zeolites, metal–organic frameworks (MOFs), and activated carbons—for their roles in CO₂ capture and long-term storage. By examining their structural features, adsorption capacities, moisture stability, and economic viability, the strengths and weaknesses of each material are assessed. Additionally, five different methods for delivering these materials into depleted oil and gas reservoirs are discussed: direct suspension injection, polymer-assisted transport, foam-assisted delivery, encapsulation with controlled release, and preformed particle gels. The potential of hybrid systems, such as MOF–carbon composites and polymer-functionalized materials, is also examined for improved selectivity and durability in underground environments. This research aims to connect materials science with subsurface engineering, helping guide the selection and use of adsorbent materials in real-world CCS applications. The findings support the optimization of CCS deployment and contribute to broader climate change efforts and the goal of achieving net-zero emissions. Key findings include CO₂ adsorption capacities of 3.5–8.0 mmol/g and surface areas up to 7000 m²/g, with MOFs demonstrating the highest uptake and activated carbons offering cost-effective performance.