Qiang Fu

The development of energy-efficient separation technologies for nitrogen (N₂)–hydrogen (H₂) mixtures under conventional industrial conditions remains a critical challenge. Adsorptive separation emerges as a promising strategy, contingent upon the design of high-performance adsorbents with tailored physicochemical properties. In this study, three isoreticular zirconium-based metal–organic frameworks (UiO-66, UiO-66-CH=CH₂, and UiO-66-F₄) are systematically evaluated for the purification of industrial N₂-H₂ mixed gases. By integrating static adsorption isotherms, dynamic breakthrough experiments, and molecular dynamics (MD) simulations, we comprehensively characterize the adsorption mechanisms and diffusion kinetics. The results demonstrate that UiO-66-F₄ exhibits optimal performance in capturing N₂ from N₂-H₂ mixtures under simulated industrial conditions, owing to its balanced binding affinity, high nitrogen uptake, and favorable micro-/mesoporous diffusion dynamics. This work offers a promising alternative for N₂-H₂ separation in industrial applications.

Hydrogen is both a clean energy carrier and an essential chemical feedstock. Its widespread adoption hinges on solid sorbents that operate efficiently at ambient temperature. Among physical materials, Ni₂(m-dobdc) featuring open Ni²⁺ sites shows strong H₂ affinity and is a leading candidate. Lithium doping further enhances room-temperature capacity, yet the dopant's location, distribution, and mechanistic role remain unclear. Here, we combine experiment with molecular simulation to investigate Li incorporation in Ni₂(m-dobdc). Grand canonical Monte Carlo and molecular dynamics simulations reveal that Li⁺ preferentially anchors at bridging oxygen sites around Ni²⁺ centers, forming a homogeneous distribution that creates additional binding sites and raises the isosteric heat of adsorption from 8.3 to 12.8 kJ mol^-1. The optimal composition, 25Li@Ni₂(m-dobdc) (LiCl/Ni₂(m-dobdc) = 0.35), achieves an excess capacity of 1.99 mmol g^-1 at 298 K and 30 bar─a 33.5% improvement over the undoped framework. This work establishes a clear structure-property relationship between controlled Li decoration and ambient-temperature hydrogen storage, with the main contribution lying in mechanistic understanding. These insights offer a rational basis for optimizing hydrogen storage performance at ambient temperature.

For industrial tail gas to be converted into high-purity hydrogen, the H₂-N₂ mixture needs to be separated efficiently. This work examined the adsorption characteristics and competitive mechanisms of H₂ and N₂ on LTA- and FAU-type zeolites, at 77 K, 298 K, and 0.1–10 bar by thoroughly analyzing results of adsorption capacity experiments and molecular simulations. In the Grand Canonical Monte Carlo (GCMC) simulations, the force field causing a molecular dipole of H₂ and the polarization force field of N₂ are first applied. The accuracy of the force field was experimentally verified. The findings indicate that N₂ and H₂ loading on Ca-FAU (Ca-LTA) are higher than Na-FAU (Na-LTA). On NaX at 77 K, the highest adsorption selectivity (N₂/H₂) is observed; on NaA at 298 K, it is the opposite. The GCMC data findings demonstrate that H₂ and N₂ have remarkably similar adsorption sites, with framework oxygen atoms and non-framework cations serving as the main adsorption sites for adsorbate molecules. Furthermore, the rate at which H₂ diffuses is higher than that of N₂. The study of redistribution charge before and after adsorption demonstrated that N₂ has a greater affinity for the framework oxygen atoms than H₂. This study provides a molecular theoretical foundation for the adsorption behavior of H₂-N₂ mixture in zeolites.

Hydrofluorocarbons (HFCs) have important applications in different industries; however, they are environmentally unfriendly due to their high global warming potential (GWP). Hence, reclamation of used hydrofluorocarbons via energy-efficient adsorption-based separation will greatly contribute to reducing their impact on the environment. In particular, the separation of azeotropic refrigerants remains challenging, such as typical mixtures of CH₂F₂ (HFC-23) and CHF₃ (HFC-32), due to a lack of adsorptive mechanisms. Metal–organic frameworks (MOFs) can provide a promising solution for the separation of CHF₃–CH₂F₂ mixtures. In this study, the adsorption mechanism of CHF₃–CH₂F₂ mixtures in TIFSIX-2-Cu-i was revealed at the microscopic level by combining static pure-component adsorption experiments, molecular simulations, and density-functional theory (DFT) calculations. The adsorption separation selectivity of CH₂F₂/CHF₃ in TIFSIX-2-Cu-i is 3.17 at 3 bar under 308 K. The existence of similar TiF₆²⁻ binding sites for CH₂F₂ or CHF₃ was revealed in TIFSIX-2-Cu-i. Interactions between the fluorine atom of the framework and the hydrogen atom of the guest molecule were found to be responsible for determining the high adsorption separation selectivity of CH₂F₂/CHF₃. This exploration is important for the design of highly selective adsorbents for the separation of azeotropic refrigerants.

Metal‐organic frameworks with high surface areas are currently being widely used for in‐depth studies on hydrogen storage with the aim of discussing the difficulties created by environmental degradation caused by the burning of fossil fuels. Understanding the effect of varied metal ion doping on adsorption position and energy is crucial to understanding the adsorption process. The adsorption behavior of NU‐1501‐Al and NU‐1501‐Fe was investigated using a combination of Grand Canonical Monte Carlo and Density Functional Theory in this study. The calculations reveal that aluminum has a larger charge than iron and higher adsorption energy. As the loading increases, hydrogen is primarily adsorbed by metal atoms and the carbon atoms of the metal‐benzene ring are connected to metal‐oxygen atoms. The research hopes to provide molecular‐level insights into the adsorption behavior of porous materials doped with different metals, which could be used to screen materials that improve gas adsorption, separation, and other expansion characteristics.

In this paper, graphite and Fe₂O₃ are introduced into MgH₂ powder by the method of hydrogenation after magnetic grinding. Hydrogen storage materials which composite of MgH₂5wt. C and MgH₂5wt. C5wt. Fe₂O₃ are successfully prepared. The physical structure of these materials was analyzed and characterized by XRD, SEM, etc. Furthermore, the influence of graphite and Fe₂O₃ on the hydrolysis of MgH₂ was systematically investigated. The results show that MgH₂CFe₂O₃ composite powder has the fastest hydrogen release rate in municipal drinking water and the highest conversion rate. Graphite and Fe₂O₃ can effectively reduce the activation energy of the hydrolysis reaction of MgH₂ and improve the hydrolysis kinetics of MgH₂. The synergistic effect of the coaddition of graphite and Fe₂O₃ can significantly increase the hydrolysis conversion rate of MgH₂ and improve the hydrolysis kinetics.

Magnesium hydride (MgH₂) is one of the competitive hydrogen storage materials on account of abundant reserves and high hydrogen content. The hydrolysis of MgH₂ is an ideal and controllable chemical hydrogen generation process. However, the hydrolyzed product of MgH₂ is a passivation layer on the surface of the magnesium hydride, which will make the reaction continuity worse and reduce the rate of hydrogen release. In this work, hydrogen generation is controllably achieved by regulating the change of the surface tension value in the hydrolysis, a variety of surfactants were systematically investigated for the effect of the hydrolysis of MgH₂ In the meantime, the passivation layer of MgH₂ was observed by scanning electron microscope (SEM), and the surface tension value of the solution with different surfactants were monitored, investing the mechanism of hydrolysis adding different surfactants. Results show that different surfactants have different effects on hydrogen generation. The hydrogen generation capacity from high to low is as follows: tetrapropylammonium bromide (TPABr), sodium dodecyl benzene sulfonate (SDBS), Ecosol 507, octadecyl trimethyl ammonium chloride (OTAC), sodium alcohol ether sulfate (AES), and fatty methyl ester sulfonate (FMES-70). When the ratio of MgH₂ to TPABr was 5:1, the hydrogen generation was increased by 52 and 28.3, respectively, at the time of 100s and 300s. When hydrolysis time exceeds 80s, the hydrogen generation with AES and FMES-70 began to decrease; it was reduced by more than 20 at the time of 300s. SEM reveals that surfactants can affect the crystalline arrangement of Mg(OH)₂ and make the passivation layer three-dimensionally layered providing channels for H₂O molecules to react with MgH₂.