Review and Perspectives on Enhancing the Hydrogen (H₂) Storage Capacity and Stability in Geological Formations via Nanoparticle-Assisted Surfactant/Polymer Formulations

Abstract

Despite numerous laboratory and simulation findings with great potential, nanoparticles (NPs), surfactants, and polymers used for enhancing hydrogen (H2) storage capacity and stability in geological formations face significant challenges. Their long-term stability is compromised in the harsh conditions of sediment heterogeneity, overly high pressure and temperature, pH changes, sediment interactions, and fluctuation in salinity, which impede large-scale implementation. Incorporating NPs into surfactants and polymers yields a nanofluid revealing increased viscosity, enhanced dispersion, improved wettability, enhanced surface interaction, H2 uptake, H2 solubility, increased retention, and long-term stability─ultimately leading to long-term H2 storage efficiency, all attributable to the synergistic effects of their components. In this research, the performance efficiency of NP-assisted surfactant/polymer formulations and the factors that impair their effectiveness were highlighted. Numerous NP-assisted surfactant/polymer formulations’ adsorption/absorption mechanisms, such as size-dependent interactions, surface charge effects, aggregation behavior, interfacial tension (IFT) modulation, H2 bonding, and hydrophobic interactions on the aqueous phase, were illustrated. The synergistic interaction of NP-assisted surfactant or polymer to the IFT reduction, improved rheological properties, flow stability, H2 adsorption, dispersion efficiency, phase retention, enhanced storage capacity, and long-term stability were also presented. Nevertheless, the extent of the synergy observed depends on the specific type and property of NPs, surfactants, or polymers used. In addition, the review highlighted the existing challenges, research gaps, and proposed potential interventions. The research uniquely bridges the gap between molecular-level interactions and field-scale applications, offering a novel synthesis of experimental and simulation data to propose actionable solutions for overcoming current limitations in H2 storage technology. By focusing on the underexplored synergy of nanoparticle-surfactant/polymer systems in geological H2 storage, this work advances the understanding of how nanoscale modifications can optimize macroscale storage efficiency and stability.