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Layered boron compounds have attracted significant interest in applications from energy storage to electronic materials to device applications, owing in part to a diversity of surface properties tied to specific arrangements of boron atoms. Here we report the energy landscape for surface atomic configurations of MgB 2 by combining first-principles calculations, global optimization, material synthesis and characterization. We demonstrate that contrary to previous assumptions, multiple disordered reconstructions are thermodynamically preferred and kinetically accessible within exposed B surfaces in MgB 2 and other layered metal diborides at low boron chemical potentials. Such a dynamic environment and intrinsic disordering of the B surface atoms present new opportunities to realize a diverse set of 2D boron structures. We validated the predicted surface disorder by characterizing exfoliated boron-terminated MgB 2 nanosheets. We further discuss application-relevant implications, with a particular view towards understanding the impact of boron surface heterogeneity on hydrogen storage performance. Layered boron compounds attract enormous interest in applications. This work reports first-principles calculations coupled with global optimization to show that the outer boron surface in MgB 2 nanosheets undergo disordering and clustering, which is experimentally confirmed in synthesized MgB 2 nanosheets.

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.

Copper ions exchanged into zeolites are active for the selective catalytic reduction (SCR) of nitrogen oxides (NOₓ) with ammonia (NH₃), but the low-temperature rate dependence on copper (Cu) volumetric density is inconsistent with reaction at single sites. We combine steady-state and transient kinetic measurements, x-ray absorption spectroscopy, and first-principles calculations to demonstrate that under reaction conditions, mobilized Cu ions can travel through zeolite windows and form transient ion pairs that participate in an oxygen (O₂)–mediated CuI→CuII redox step integral to SCR. Electrostatic tethering to framework aluminum centers limits the volume that each ion can explore and thus its capacity to form an ion pair. The dynamic, reversible formation of multinuclear sites from mobilized single atoms represents a distinct phenomenon that falls outside the conventional boundaries of a heterogeneous or homogeneous catalyst.

Nanomaterials have revolutionized the battery industry by enhancing energy storage capacities and charging speeds, and their application in hydrogen (H 2 ) storage likewise holds strong potential, though with distinct challenges and mechanisms. H 2 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 H 2 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 H 2 storage systems by optimizing H 2 adsorption at the nanoscale and improving the kinetics of H 2 uptake and release. We discuss various H 2 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 H 2 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 H 2 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.

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 Li 2 Mg(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 Li 2 Mg(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.

Zeolites are three-dimensional, crystalline silicate-based materials of interest for catalysis and separations. Computational models of zeolites must capture their three-dimensional structure, the intrinsic microscopic heterogeneity introduced by heteroatom substitutions that underlie their interesting chemical behavior, and the dynamic nature of reactive sites within the pores of molecular dimensions. In this dissertation, I will describe my use of supercell density functional theory (DFT) models for tackling these problems, focusing primarily on Brønsted acidic, Fe or Cu-exchanged chabazite (CHA) zeolites and their relationship to the catalytic chemistry of nitrogen oxides (NOx) and the partial oxidation of methane. In addition, I will also show how DFT computations are used to gain insights into the in uence of extra-framework cations on zeolite property during synthesis. I will describe considerations important in model construction, applications of ab initio molecular dynamics to structure annealing and accurate computations of reaction and activation free energies, first-principles thermodynamics approaches for predicting site speciation at realistic conditions, and approaches for predicting heteroatom distributions into material models.

Copper ions in zeolites help remove noxious nitrogen oxides from diesel exhaust by catalyzing their reaction with ammonia and oxygen. Paolucci et al. found that these copper ions may move about during the reaction (see the Perspective by Janssens and Vennestrom). Zeolite catalysts generally fix metals in place while the reacting partners flow in and out of their cagelike structures. In this case, though, x-ray absorption spectroscopy suggested that the ammonia was mobilizing the copper ions to pair up as they activated oxygen during the catalytic cycle. Science , this issue p. 898 ; see also p. 866 Copper ions can move about and pair up in a zeolite framework as they catalyze nitric oxide removal from diesel exhaust. Copper ions exchanged into zeolites are active for the selective catalytic reduction (SCR) of nitrogen oxides (NO x ) with ammonia (NH 3 ), but the low-temperature rate dependence on copper (Cu) volumetric density is inconsistent with reaction at single sites. We combine steady-state and transient kinetic measurements, x-ray absorption spectroscopy, and first-principles calculations to demonstrate that under reaction conditions, mobilized Cu ions can travel through zeolite windows and form transient ion pairs that participate in an oxygen (O 2 )–mediated Cu I →Cu II redox step integral to SCR. Electrostatic tethering to framework aluminum centers limits the volume that each ion can explore and thus its capacity to form an ion pair. The dynamic, reversible formation of multinuclear sites from mobilized single atoms represents a distinct phenomenon that falls outside the conventional boundaries of a heterogeneous or homogeneous catalyst.

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.

Epoxide-functionalization has emerged as an effective strategy for enhancing the oxidative stability of poly(ethylenimine)-based CO2 capture sorbents. However, the underlying mechanism remains largely unexplored. Here we combine first-principles modeling, material synthesis, and characterizations to investigate the impact of epoxide-functionalization on hydrogen bonding and mobility in poly(ethylenimine) (PEI). Blue-moon ensemble and deep potential molecular dynamics simulations reveal that epoxide-functionalization leads to stronger hydrogen bonding involving hydroxyl groups. Synthesized branched PEI samples with and without propylene-oxide (PO) functionalization are characterized using DSC, NMR relaxometry, and fluorescent probes, demonstrating that PO-functionalization significantly reduces BPEI mobility. These findings suggest that the enhanced oxidative stability of epoxide-functionalized PEI can be attributed to the formation of strong hydrogen bonds with hydroxyl groups, which restrict the mobility of PEI and decelerate mobility-dependent radical propagation reactions responsible for polymer degradation. Strategies for further tuning hydrogen bond environment are proposed based on these findings.