Rare-earth-metal-based materials have emerged as frontrunners in the quest for high-performance hydrogen storage solutions, offering a paradigm shift in clean energy technologies. This comprehensive review delves into the cutting-edge advancements, challenges, and future prospects of these materials, providing a roadmap for their development and implementation. By elucidating the fundamental principles, synthesis methods, characterization techniques, and performance enhancement strategies, we unveil the immense potential of rare-earth metals in revolutionizing hydrogen storage. The unique electronic structure and hydrogen affinity of these elements enable diverse storage mechanisms, including chemisorption, physisorption, and hydride formation. Through rational design, nanostructuring, surface modification, and catalytic doping, the hydrogen storage capacity, kinetics, and thermodynamics of rare-earth-metal-based materials can be significantly enhanced. However, challenges such as cost, scalability, and long-term stability need to be addressed for their widespread adoption. This review not only presents a critical analysis of the state-of-the-art but also highlights the opportunities for multidisciplinary research and innovation. By harnessing the synergies between materials science, nanotechnology, and computational modeling, rare-earth-metal-based hydrogen storage materials are poised to accelerate the transition towards a sustainable hydrogen economy, ushering in a new era of clean energy solutions.

Lithium borohydride (LiBH₄) has emerged as a promising hydrogen storage material due to its exceptional theoretical hydrogen capacity (18.5 wt.%). However, its practical application is hindered by high dehydrogenation temperature (>400 °C), sluggish kinetics, and limited reversibility due to stable intermediate formation. This review critically analyzes recent advances in LiBH₄ modification through three primary strategies: catalytic enhancement, nanostructure engineering, and reactive composite design. Advanced carbon architectures and metal oxide catalysts demonstrate significant improvements in reaction kinetics and cycling stability through interface engineering and electronic modification. Sophisticated nanostructuring approaches, including mechanochemical processing and infiltration techniques, enable precise control over material architecture and phase distribution, effectively modifying thermodynamic and kinetic properties. The development of reactive hydride composites, particularly LiBH₄-MgH₂ systems, provides promising pathways for thermodynamic destabilization while maintaining high capacity. Despite these advances, challenges persist in maintaining engineered structures and suppressing intermediate phases during cycling. Future developments require integrated approaches combining multiple modification strategies while addressing practical implementation requirements.

The advancement of solid-state hydrogen storage materials is critical for the realization of a sustainable hydrogen economy. This comprehensive review elucidates the state-of-the-art characterization techniques employed in solid-state hydrogen storage research, emphasizing their principles, advantages, limitations, and synergistic applications. We critically analyze conventional methods such as the Sieverts technique, gravimetric analysis, and secondary ion mass spectrometry (SIMS), alongside composite and structure approaches including Raman spectroscopy, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM). This review highlights the crucial role of in situ and operando characterization in unraveling the complex mechanisms of hydrogen sorption and desorption. We address the challenges associated with characterizing metal-based solid-state hydrogen storage materials discussing innovative strategies to overcome these obstacles. Furthermore, we explore the integration of advanced computational modeling and data-driven approaches with experimental techniques to enhance our understanding of hydrogen–material interactions at the atomic and molecular levels. This paper also provides a critical assessment of the practical considerations in characterization, including equipment accessibility, sample preparation protocols, and cost-effectiveness. By synthesizing recent advancements and identifying key research directions, this review aims to guide future efforts in the development and optimization of high-performance solid-state hydrogen storage materials, ultimately contributing to the broader goal of sustainable energy systems.

Hydrogen peroxide (H₂O₂), an accessible and eco-friendly oxidant, was employed for the template-free hydrothermal synthesis of mesoporous CeO₂ based on a cerium carbonate precursor (Ce₂(CO₃)₃•xH₂O). Its microstructure and physicochemical properties were characterized by XRD, TEM and N₂ sorption techniques. The formation of the CeO₂ phase with a porous structure was strongly dependent on the presence of H₂O₂, while the values of the BET surface area, pore diameter and pore volume of CeO₂ were generally related to the amount of H₂O₂ in the template-free hydrothermal synthesis. The BET surface area and pore volume of the mesoporous CeO₂ synthesized hydrothermally at 180 °C with 10 mL H₂O₂ were 112.8 m²/g and 0.1436 cm³/g, respectively. The adsorption process had basically finished within 30 min, and the maximum adsorption efficiency within 30 min was 99.8% for the mesoporous CeO₂ synthesized hydrothermally at 140 °C with 10 mL, when the initial AO7 concentration was 120 mg/L without pH preadjustment. The experimental data of AO7 adsorption were analyzed using the Langmuir and Freundlich isotherm modes. Moreover, the mesoporous CeO₂ synthesized at 140 °C with 10 mL H₂O₂ was regenerated in successive adsorption–desorption cycles eight times without significant loss in adsorption capacity, suggesting that the as-synthesized mesoporous CeO₂ in this work was suitable as an adsorbent for the efficient adsorption of AO7 dye from an aqueous solution.

Bamboo is known as the “world’s second largest forest”. The bamboo industry has become a globally recognized green industry, and the research and development of bamboo-based products have huge economic, ecological, and cultural values. In this study, a biosorbent with magnetically sensitive properties was developed based on natural bamboo powders (BPs) for the removal of methylene blue (MB) dye from aqueous solution. The selected BPs with 60 mesh were magnetized by loading Fe₃O₄ using an in situ co-precipitation process. The adsorption–desorption equilibrium was nearly established after 30 min, achieving a removal efficiency of 97.7% for 5.0 g/L BPs/Fe₃O₄ in a 20 mg/L MB solution. The removal efficiency of MB by 5.0 g/L BPs/Fe₃O₄ exhibited a remarkable enhancement, escalating from 33.9% at pH = 5 to an impressive 93.9% at pH = 11 in a 50 mg/L MB solution. The linear fitting method demonstrated greater suitability for characterizing the adsorption process compared to the nonlinear fitting method, which encompassed both adsorption isotherms and kinetics studies. Among these approaches, the adsorption isotherms were well-fitted to the Langmuir model, while the kinetics were accurately represented by the pseudo-second-order model. The removal efficiency by the recycled BPs/Fe₃O₄ adsorbent remained at 97.3% over five consecutive cycles, proving that BPs/Fe₃O₄ has a high potential for being used as a highly efficient biosorbent. Moreover, the BPs/Fe₃O₄ biosorbent had superparamagnetism with strong magnetic sensitivity, which could facilitate the sustainable removal of hazardous dye from the aqueous solution in practical applications.

To further enhance the safety and energy efficiency of the Fe₃O₄ preparation experiment, we proposed a strategy for synthesizing monodisperse Fe₃O₄ microspheres through a one-step solvothermal process. In this environmentally friendly synthesis method, stable FeCl₃∙6H₂O was utilized as the sole raw material, while ethylene glycol, characterized by its high boiling point and favorable safety profile, served as the solvent. Additionally, inexpensive and readily available urea was selected to function either as a mineralizer or surfactant. Through this one-step solvothermal reaction, the target product of Fe₃O₄ could be obtained without subsequent calcination under reducing or inert atmospheres, thereby enhancing experimental safety and promoting energy conservation. By controlling the amount of urea added, it became feasible to produce monodisperse magnetic Fe₃O₄ microspheres characterized by complete crystallinity and high yield. Utilizing the as-synthesized Fe₃O₄ as a catalyst, we investigated its photocatalytic activity against xylenol orange organic dyes along with its regeneration characteristics. When 40 mmol of urea was incorporated into the reaction mixture, the resulting Fe₃O₄ sample exhibited optimal photocatalytic performance; a 20 mg/L xylenol orange solution became colorless and transparent after just 1.5 h of UV light irradiation. Furthermore, during five consecutive regeneration cycles, its catalytic activity could be restored to its initial level. Importantly, Fe₃O₄ demonstrated excellent magnetic sensitivity properties that facilitated rapid targeted separation under an external magnetic field, providing convenience for recovery and collection purposes.