Nano-enhanced solid-state hydrogen storage: Balancing discovery and pragmatism for future energy solutions

Nanomaterials have revolutionized the battery industry by enhancing energy storage capacities and charging speeds, and their application in hydrogen (H2) storage likewise holds strong potential, though with distinct challenges and mechanisms. H2 is a crucial future zero-carbon energy vector given its high gravimetric energy density, which far exceeds that of liquid hydrocarbons. However, its low volumetric energy density in gaseous form currently requires storage under high pressure or at low temperature. This review critically examines the current and prospective landscapes of solid-state H2 storage technologies, with a focus on pragmatic integration of advanced materials such as metal-organic frameworks (MOFs), magnesium-based hybrids, and novel sorbents into future energy networks. These materials, enhanced by nanotechnology, could significantly improve the efficiency and capacity of H2 storage systems by optimizing H2 adsorption at the nanoscale and improving the kinetics of H2 uptake and release. We discuss various H2 storage mechanisms—physisorption, chemisorption, and the Kubas interaction—analyzing their impact on the energy efficiency and scalability of storage solutions. The review also addresses the potential of “smart MOFs”, single-atom catalyst-doped metal hydrides, MXenes and entropy-driven alloys to enhance the performance and broaden the application range of H2 storage systems, stressing the need for innovative materials and system integration to satisfy future energy demands. High-throughput screening, combined with machine learning algorithms, is noted as a promising approach to identify patterns and predict the behavior of novel materials under various conditions, significantly reducing the time and cost associated with experimental trials. In closing, we discuss the increasing involvement of various companies in solid-state H2 storage, particularly in prototype vehicles, from a techno-economic perspective. This forward-looking perspective underscores the necessity for ongoing material innovation and system optimization to meet the stringent energy demands and ambitious sustainability targets increasingly in demand

Hydrogen storage in complex hydrides: past activities and new trends

publishedVersio

Hydrogen storage in complex hydrides: Past activities and new trends

Intense literature and research efforts have focussed on the exploration of complex hydrides for energy storage applications over the past decades. A focus was dedicated to the determination of their thermodynamic and hydrogen storage properties, due to their high gravimetric and volumetric hydrogen storage capacities, but their application has been limited because of harsh working conditions for reversible hydrogen release and uptake. The present review aims at appraising the recent advances on different complex hydride systems, coming from the proficient collaborative activities in the past years from the research groups led by the experts of the Task 40 'Energy Storage and Conversion Based on Hydrogen' of the Hydrogen Technology Collaboration Programme of the International Energy Agency. An overview of materials design, synthesis, tailoring and modelling approaches, hydrogen release and uptake mechanisms and thermodynamic aspects are reviewed to define new trends and suggest new possible applications for these highly tuneable materials

Detecting Reactive Products in Carbon Capture Polymers with Chemical Shift Anisotropy and Machine Learning

Aminopolymers are attractive sorbents for CO2 direct air capture applications as their amines readily react with atmospheric levels of CO2 to form chemisorbed species. The identity of the chemisorbed species varies upon experimental conditions like amine chemistry, support material, CO2 loading, and humidity, forming a variety of carbonyl-type sites. 13C solid-state nuclear magnetic resonance (NMR) is often used to help elucidate the identity of the chemisorbed species however the chemical shift range for carbonyl sites is small and comparable to observed chemisorbed 13C peak widths. Herein, application of a 2D chemical shift anisotropy (CSA) recoupling pulse sequence (ROCSA) is used to obtain CSA tensor values at each isotropic chemical shift, overcoming the isotropic peak resolution limitation. CSA tensor values describe the local chemical environment and can readily differentiate between chemisorbed products. To aid this experimental technique, we also developed a k-nearest-neighbor (KNN) classification model to distinguish chemisorbed compounds via their CSA tensor parameters. The combination of 2D CSA measurements coupled with a KNN classification model enhances the ability to accurately identify chemisorbed products especially in the case of mixtures. This methodology is demonstrated on poly(ethylenimine) in a solid-support γ-Al2O3 exposed to CO2 followed by incomplete regeneration at 100 °C and shows a mixture of strongly bound chemisorbed products, ammonium carbamate and urea

Deep Neural Network Potential Demonstrates the Impact of Proton Transfer in CO2 Capture by Liquid Ammonia

The direct air capture of CO2 using aminopolymers can reduce the environmental impact caused by the still growing anthropogenic emissions of CO2 to the atmosphere. Despite the adsorption efficiency of aminopolymers even in ultradilute conditions, the mechanism of CO2 binding in condensed phase amines is still poorly understood. This work combines machine learning potentials, enhanced sampling and Grand Canonical Monte Carlo to directly compute experimentally-relevant quantities, such as the free energy and enthalpy of CO2 adsorption. Our free energy calculations elucidate the important role of solvent-mediated proton transfer on the formation of the most stable CO2-bound species: carbamate and carbamic acid. Liquid ammonia is used as a model system to study CO2 adsorption, but the methodology can be extended to amines with more complex chemical structure. The study of CO2 adsorption using machine learning brings computer simulations closer to the thermodynamic conditions of interest to experiments, thus paving the way to a more detailed study between the chemical composition of amines and their CO2 binding affinity

Effect and mechanism of T lymphocytes on human induced pluripotent stem cell-derived cardiomyocytes via Proteomics

Abstract Background Abnormalities in T cell activation play an important role in the pathogenesis of myocarditis, and persistent T cell responses can lead to autoimmunity and chronic cardiac inflammation, as well as even dilated cardiomyopathy. Although previous work has examined the role of T cells in myocarditis in animal models, the specific mechanism for human cardiomyocytes has not been investigated. Methods In this study, we constructed the human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) and established the T cell-mediated cardiac injury model by co-culturing with activated CD4 + T or CD8 + T cells that were isolated from peripheral mononuclear blood to elucidate the pathogenesis of myocardial cell injury caused by inflammation. Results By combination of quantitative proteomics with tissue and cell immunofluorescence examination, we established a proteome profile of inflammatory myocardia from hiPSC-CMs with obvious cardiomyocyte injury and increased levels of lactate dehydrogenase content, creatine kinase isoenzyme MB and cardiac troponin. A series of molecular dysfunctions of hiPSC-CMs was observed and indicated that CD4 + cells could produce direct cardiomyocyte injury by activating the NOD-like receptor signals pathway. Conclusions The data presented in our study established a proteome map of inflammatory myocardial based on hiPSC-CMs injury model. These results can provide guidance in the discovery of improved clinical treatments for myocarditis

Contributions of CO2, O2 and H2O to the Oxidative Stability of Solid Amine Direct Air Capture Sorbents at Intermediate Temperature

Aminopolymer-based sorbents are preferred materials for extraction of CO2 from ambient air (direct air capture of CO2, or DAC) owing to their high CO2 adsorption capacity and selectivity at ultra dilute conditions. While those adsorptive properties are important, the stability of a sorbent is a key element in developing high-performing, cost-effective, and long-lasting sorbents that can be deployed at scale. Along with process upsets, environmental components such as CO2, O2, and H2O may contribute to long-term sorbent instability. As such, unraveling the complex effects of such atmospheric components on sorbent lifetime as they appear in the environment is a critical step to understanding sorbent deactivation mechanisms and designing more effective sorbents and processes. Here, PEI/Al2O3 sorbent is assessed over continuous and cyclic dry and humid conditions to determine the effect of the co-presence of CO2 and O2 on stability at an intermediate temperature of 70 °C. Thermogravimetric and elemental analysis in combination with in situ HATR-IR spectroscopy are performed to measure the extent of deactivation, elemental content, and molecular level changes in the sorbent due to deactivation. The thermal/thermogravimetric analysis results reveal that incorporating CO2 with O2 accelerates sorbent deactivation using these sorbents in dry and humid conditions compared to CO2-free air in similar conditions. In situ HATR-IR spectroscopy results of PEI deactivation under a CO2-air environment show the formation of primary amine species in higher quantity (compared to conditions without O2 or CO2), which arise due to C-N bond cleavage at the primary and secondary amine due to oxidative degradation. We hypothesize the formation of bound CO2 species such as carbamic acids catalyze C-N cleavage reactions in the oxidative degradation pathway by shuttling protons, resulting in a lower activation energy barrier for degradation, as probed by metadynamics simulations. In the cyclic experiment after 30 cycles, results show a gradual loss in stability (dry: 29%, humid: 52%) under CO¬2 containing air (0.04% CO2/21% O2 balance N2). However, the loss in capacity during cyclic studies is significantly less than continuous deactivation as expected

Experimental and Computational Interrogation of Fast SCR Mechanism and Active Sites on H‑Form SSZ-13

Experiments and density functional theory (DFT) models are combined to develop a unified, quantitative model of the mechanism and kinetics of fast selective catalytic reduction (SCR) of NO/NO₂ mixtures over H-SSZ-13 zeolite. Rates, rate orders, and apparent activation energies collected under differential conditions reveal two distinct kinetic regimes. First-principles thermodynamics simulations are used to determine the relative coverages of free Brønsted sites, chemisorbed NH₄⁺, and physisorbed NH₃ as a function of reaction conditions. First-principles metadynamics calculations show that all three sites can contribute to the rate-limiting N–N bond forming step in fast SCR. The results are used to parametrize a kinetic model that encompasses the full range of reaction conditions and recovers observed rate orders and apparent activation energies. Observed kinetic regimes are related to changes in most-abundant surface intermediates

A Nanoscale Ternary Amide‐rGO Composite with Boosted Kinetics for Reversible H2 Storage

Metal amides are attractive candidates for hydrogen storage due to their high volumetric and gravimetric hydrogen densities. However, the sluggish kinetics and competing side reactions during hydrogen uptake and release limit their practical use. Here, a novel nanoconfined Li2Mg(NH)2@reduced graphene oxide (rGO) composite is presented, which is fabricated using a melt-infiltration method with a minimum weight penalty of only 2 wt.%. The presence of rGO ensures close contact between the active phases, effectively preventing aggregation during cycling process. As a result, the reversible capacity of Li2Mg(NH)2@rGO reaches 4.42 wt.%, with no capacity degradation observed after multiple cycling. Theoretical calculations show that rGO catalyzes the hydrogen bond cleavage at the Mg-amide/Li hydride interface, leading to local dehydrogenation hotspots and significantly improves kinetics of dehydrogenation compared to the bulk counterpart. This study provides a promising strategy for designing metal imide-based composites to overcome the kinetic limitations and improve their reversible hydrogen storage performance