Near-ambient Conditions Research Articles

Low-power electrodeless 2.45 GHz microwave plasma generation in ambient air with dielectric resonators

Abstract Microwave (MW) plasma, as an electrodeless non-thermal plasma technique, holds significant potential for gas processing applications under near-ambient conditions. However, current MW plasma methods suffer from low energy efficiency due to the high power required for molecular breakdown via vibrational excitation. A promising approach to mitigate this challenge involves using a pair of high relative permittivity dielectric resonators (DRs) in close proximity to enhance the electric field within the small gap between them, thus reducing power consumption. In this study, we combined simulations and experiments to investigate the electric field enhancement effect of DRs with varying shapes, geometrical parameters (e.g., radius and height), gap distances, and orientations relative to the electric field polarization and MW propagation directions. Simulations performed using Ansys HFSS demonstrate that edge-to-edge configurations of hexagonal, square, and triangular prism DRs can achieve significant electric field enhancement over a broad range of geometric parameters. DRs fabricated from calcium titanate were tested experimentally using a simple setup with a kitchen microwave (2.45 GHz) at ambient pressure. With input power below 100 W, stable and highly confined plasma was generated using hexagonal and triangular prism DRs. These results suggest a simple, cost-effective, and low-power method for generating MW plasma under ambient conditions, offering particular advantages for chemical processing in rural areas utilizing renewable energy resources.

Electrochemical Ammonia Synthesis: The Energy Efficiency Challenge.

We discuss the challenges associated with achieving high energy efficiency in electrochemical ammonia synthesis at near-ambient conditions. The current Li-mediated process has a theoretical maximum energy efficiency of ∼28%, since Li deposition gives rise to a very large effective overpotential. As a starting point toward finding electrocatalysts with lower effective overpotentials, we show that one reason why Li and alkaline earth metals work as N2 reduction electrocatalysts at ambient conditions is that the thermal elemental processes, N2 dissociation and NH3 desorption, are both facile at room temperature for these metals. Many transition metals, which have less negative reduction potentials and thus lower effective overpotentials, can dissociate N2 at these conditions but they all bind NH3 too strongly. Strategies to circumvent this problem are discussed, as are the other requirements for a good N2 reduction electrocatalyst.

A multi-molecular beam/infrared reflection absorption spectroscopy apparatus for probing mechanisms and kinetics of heterogeneously catalyzed reaction from ultrahigh vacuum to near-ambient pressure conditions.

A novel multi-molecular beam/infrared reflection absorption spectroscopy (IRAS) apparatus is described, which was constructed for studying mechanisms and kinetics of heterogeneously catalyzed reactions following a rigorous surface science approach in the pressure range from ultrahigh vacuum (UHV, 1 × 10-10mbar) to near-ambient pressure (NAP, 1000mbar) conditions. The apparatus comprises a preparation chamber equipped with standard surface science tools required for the preparation and characterization of model heterogeneous catalysts and two reaction chambers operating at different pressure ranges: in UHV and in the variable pressure range up to NAP conditions. The UHV reaction chamber contains two effusive molecular beams (flux up to 1.1 × 1015 molecules cm-2s-1), a quadrupole mass spectrometer, a Fourier-Transform (FT) IRA spectrometer, and a molecular beam monitor for beam aligning. This combination of the methods allows us to independently dose different reactants on the surface in a highly controlled way while simultaneously monitoring the evolution of gaseous products by QMS and recording the evolution of the surface species by FT-IRAS. The second reaction chamber operating in the variable pressure range is equipped with polarization-modulation-IRAS and three gas dosers and is designed as a small reactor, which can be operated in a continuous flow mode. The sample prepared under well-controlled UHV conditions can be in situ transferred between all chambers, thus allowing for investigations of structure-reactivity relationships over model surfaces. In this contribution, we provide a detailed description of the apparatus and the test measurements of the different crucial parts of the apparatus in the variable pressure range.

Growth and Transformation of Hydrated Magnesium Carbonates under Near-Ambient Conditions

Growth and Transformation of Hydrated Magnesium Carbonates under Near-Ambient Conditions

First-Principles Study of Titanium-Doped B7 Cluster for High Capacity Hydrogen Storage.

The geometrical structure, stability, electronic properties, and hydrogen storage capabilities of a titanium-doped B7 cluster was calculated using density functional theory computations. The results show that the TiB7 cluster is predicted to be stable under near-ambient conditions based on an ab initio molecular dynamic simulation. The transition state analysis found that the H2 molecule can dissociate on the TIB7 cluster surface to form a hydride cluster. The Ti atom within the TiB7 cluster demonstrates an impressive capacity to adsorb up to five H2 molecules, achieving a peak hydrogen storage mass fraction of 7.5%. It is worth noting that the average adsorption energy of H2 molecules is 0.27-0.32 eV, which shows that these configurations are suited for reversible hydrogen storage under mild temperature and pressure regimes. In addition, calculations found that both polarization and hybridization mechanisms play pivotal roles in facilitating the adsorption of H2 molecules onto the TiB7 cluster. Our research results show that the TiB7 cluster has potential for hydrogen storage applications under near-ambient conditions.

Construction of carbon nanotube-multifunctional porous ionic polymer core–shell nanocomposite for efficient conversion of carbon dioxide under co-catalyst free conditions

Metalated porous ionic polymers featuring multiple active sites show significant potential for carbon dioxide (CO2) fixation. However, general and efficient strategies to enhance their catalytic efficiency still remain to be developed. Herein, carbon nanotube-multifunctional ionic polymer core–shell composite (CNT@P(TBr-Py)-ZnBr2) was easily prepared by a solvothermal radical copolymerization strategy, followed by metallization with ZnBr2. Characterization revealed that the synthesized composite exhibited a distinct core–shell tubular nanostructure, with CNT serving as the core, and multifunctional polymer containing Lewis acid (Zn), nucleophilic Br¯ and CO2-philic triazine groups as the shell. Furthermore, the composite displayed broad pore size distribution and large average pore size. Impressively, CNT@P(TBr-Py)-ZnBr2 delivered an outstanding catalytic efficiency in the cycloaddition of CO2 to epichlorohydrin, surpassing the control catalysts poly(triazine-based vinyl ionic liquid) (PTBr), bipyridine-functionalized porous ionic polymer (P(TBr-Py), and ZnBr2 metalated P(TBr-Py) (P(TBr-Py)-ZnBr2) by factors of 5.4, 5.8, and 1.3, respectively. At 140 °C, a high turnover frequency (TOF) of 11174 h−1 and a 93.4 % yield of target cyclic carbonate were achieved in the absence of any additional co-catalyst. This exceptional catalytic performance of CNT@P(TBr-Py)-ZnBr2 can be mainly attributed to its unique core–shell structure, along with the synergistic catalytic effect of its multifunctional active sites. Also, the reaction can proceed smoothly under near-ambient conditions (30 °C, 1 bar CO2), though a longer reaction time was required. Additionally, CNT@P(TBr-Py)-ZnBr2 demonstrated a wide range of substrate compatibility and excellent recycling stability. This work therefore presents a viable approach for designing efficient and multifunctional ionic polymer-based catalysts for CO2 fixation.

Synergistic Electronic Interaction in PdCu Alloy/TiO2-NSs for Ambient Efficient Dehydrogenation of Formic Acid.

Palladium-based catalysts are remarkable in endorsing hydrogen (H2) generation through formic acid (HCOOH, FA) dehydrogenation under near-ambient conditions. Hydrogen energy efficiency depends on high-performance catalyst design. In this study, Pd-Cu nanoalloy catalysts with mutable atomic ratios are successfully fabricated on TiO2 nanosheets (TiO2-NSs).The synergistic electronic interactions between Palladium (Pd) and copper (Cu) are revealed through a density of states (DOS) analysis of alloy supported over a mixed valence state of Ti linked to oxygen vacancies (Vo) in TiO2-NSs, Enhanced adsorption of target molecules reveals novel active sites for Formic acid dehydrogenation (FAD), with O─H bond cleavage via HCOO formate intermediate preceding C─H and C─O bond cleavage. Experimental and theoretical research demonstrates that the Pd-Cu/TiO2-NSs (3:7) catalyst d electron redistribution and d-band center shift lower the activation energy for O─H bond cleavage, exhibit superior H2 production than pure Pd and Cu, increasing Pd electron density due to synergistic effects from reactive crystal facets, defects, and strong metal support interactions (SMSI), lowering the activation energy for HCOOH dissociation step, generating carbon dioxide (CO2) and H2 with a unprecedented high turnover frequency (TOF) of 6268 molH2.h-1.molPd-1 at 303K with activation energy (Ea) of 15 KJ mol-1. This attempt models an efficient HCOOH-to-hydrogen catalyst.

Borate Pathway to FAMEs at Near-Ambient Conditions from Used Oil

Borate Pathway to FAMEs at Near-Ambient Conditions from Used Oil

Agarose derived carbon based nanocomposite for hydrogen storage at near-ambient conditions

Nanocomposites of high surface area adsorption materials and nanosized transition metals have emerged as a promising strategy for hydrogen storage applications. However, their potential use in both transport and stationary applications depends on reaching the ultimate storage capacity at near-ambient conditions along with scalable synthesis protocols. Herein, a direct and simple thermal decomposition technique is reported to synthesize carbon-based nanocomposite, where nickel nanoparticles are dispersed in a porous carbon matrix. It is also demonstrated that the storage capacity can be enhanced at near-ambient conditions by effectively engineering the microstructure and synergistically combining the ‘physisorption’ and ‘spillover’ mechanism. The structure, composition and morphology of the samples were investigated using X-ray diffraction, energy dispersive spectroscopy, transmission and scanning electron microscopy. Sorption-desorption isotherms were obtained to study the hydrogen storage capacity at a moderate H2 pressure of 20 bar. The nanocomposite showed a promising storage capacity of 0.73 wt% at 298 K with reversible cyclability. It is shown that the uniform dispersion of catalytic nanoparticles leads to an increase in the spillover efficiency, which further helps in the enhancement of hydrogen storage capacity by a factor of 6.5 over pure carbon.

Adsorbate-induced adatom formation on Au-Cu bimetallic alloys and its possible consequences for CO2 electroreduction

The adsorbate-induced formation of sub-nanometer clusters on transition-metal single crystals observed in previous high-pressure microscopic studies hinted at the in-situ formation of unique active sites even on large nanoparticle catalysts. We propose that the adatom formation energy can be used as an energetic descriptor for the initial step toward the adsorbate-induced metal-cluster formation process. This descriptor can be efficiently computed using density functional theory (DFT) calculations and applied for screening and identification of metal catalysts where this phenomenon may play an important role in generating active sites in-situ. As a proof of concept, here, we construct an adatom formation energy database for three AuxCuy alloys (x:y = 3:1, 1:1, or 1:3) and eighteen adsorbates (H, C, N, O, F, S, Cl, Br, I, CHx, NHx (x = 1 – 3), CO, NO, and OH) commonly involved in catalytic reactions. The energetics of adatom formation were examined in all cases where the (111) terrace, (211) step-edge, and (874) kink were the sources of the adatom. We demonstrate that the presence of an adsorbate could alter not only the energetics for adatom formation but also the elemental nature of the preferred adatom being formed. Using our database, we identified promising systems which favor adsorbate-induced adatom formation under near-ambient conditions. Specifically, CO-induced adatom formation on all three Au-Cu alloy surfaces could occur under CO2 electroreduction (CO2RR) conditions. This phenomenon offers a qualitative explanation for the experimentally observed CO2RR activity on Au-Cu alloy catalysts. Our methodology offers an easily expandable and efficient approach for large-scale catalyst screening with regards to adatom/cluster formation under reaction conditions and provides insight into the possible nature of active sites on alloy catalysts from a novel perspective.

Introducing Noble Gas as Space Holder under High Pressure to Design Porous Titanium Carbides with Open Metal Sites for Hydrogen Storage at Near-Ambient Conditions.

It has been a long-standing challenge to develop high-performance solid-state hydrogen storage materials operated under near-ambient conditions. In this work, we propose a new strategy of using noble gases for space holding to design porous titanium carbides with abundant open metal sites for hydrogen storage. By using machine learning and graph theory-assisted universal structure searching methods, we obtain 28 porous titanium carbides from three precursors (TiC dimer, C atom, and Kr atom) under 30 GPa of pressure. The stability and hydrogen storage performance of the resulting structures are further assessed and validated through density function theory and grand canonical Monte Carlo simulations with a DFT-fitted force field. Finally, p-TiC2 is identified as a promising quasi-molecular hydrogen storage material with capacity of 4.0 wt % and 106.0 g/L at 230 K and 16 bar.

Theoretical investigation of mixed-metal metal-organic frameworks as H2 adsorbents: insights from GCMC and DFT simulations

ABSTRACT Molecular hydrogen ( H 2 ) is a renewable energy carrier, however, its practical applications are limited due to the challenges of developing safe and efficient H 2 storage devices. Metal Organic Frameworks (MOFs) containing at least two different metal ions in their structures are called as mixed-metal MOFs (MM-MOFs) and they could adsorb H 2 in higher amounts compared to structures containing single metal nodes. We theoretically examined the H 2 storage capacities of 26 MM-MOFs having various physical and chemical properties applying Grand Canonical Monte Carlo (GCMC) and Density Functional Theory (DFT) simulations. H 2 adsorption isotherms were calculated using a five-site anisotropic H 2 model. QIXSOG, YOMVIG, OSOYUR, Cu-Mg-BTC, Fe-Mg-BTC, and Cr-Mg-BTC were selected as top-performing MM-MOFs maximising H 2 adsorption gravimetrically and volumetrically at near-ambient conditions (233 K and 100 bar), approaching the DOE targets. YOMVIG has the largest H 2 adsorption enthalpy, calculated as − 9.93 kJ/mol at 233 K and 100 bar. DFT simulations have been conducted to analyse preferable H 2 adsorption sites as well as identify guest-host interactions. Electron density difference analysis showed that adsorbed H 2 molecules in the OSOYUR, Cr-Mg-BTC, Cu-Mg-BTC, and Fe-Mg-BTC are polarised. Our study challenges existing literature by identifying promising MM-MOFs as potential next-generation hydrogen storage adsorbents at near-ambient conditions.

Molecular hydrogen in the N-doped LuH3 system as a possible path to superconductivity

The discovery of ambient superconductivity would mark an epochal breakthrough long-awaited for over a century, potentially ushering in unprecedented scientific and technological advancements. The recent findings on high-temperature superconducting phases in various hydrides under high pressure have ignited optimism, suggesting that the realization of near-ambient superconductivity might be on the horizon. However, the preparation of hydride samples tends to promote the emergence of various metastable phases, marked by a low level of experimental reproducibility. Identifying these phases through theoretical and computational methods entails formidable challenges, often resulting in controversial outcomes. In this paper, we consider N-doped LuH3 as a prototypical complex hydride: By means of machine-learning-accelerated force-field molecular dynamics, we have identified the formation of H2 molecules stabilized at ambient pressure by nitrogen impurities. Importantly, we demonstrate that this molecular phase plays a pivotal role in the emergence of a dynamically stable, low-temperature, experimental-ambient-pressure superconductivity. The potential to stabilize hydrogen in molecular form through chemical doping opens up a novel avenue for investigating disordered phases in hydrides and their transport properties under near-ambient conditions.

Reversible hydrogen storage with Na-modified Irida-Graphene: A density functional theory study

Two-Dimensional carbon-based materials as a potential hydrogen storage medium have attracted great attention. In this study, various key aspects such as structure, electronic properties, stability, and hydrogen storage performance of Na-modified Irida-Graphene (IG) were thoroughly investigated using density functional theory (DFT) calculation methods. The calculation results show that the binding energy of Na atoms with the substrate is 1.51 eV, far exceeding the cohesive energy. The AIMD results reflect the good thermal stability of the model. One Na atom can adsorb up to 5H2 molecules. The IG loaded with eight Na atoms on both sides can adsorb 32H2 molecules, achieving a hydrogen storage capacity of 7.82 wt%, far exceeding the US DOE target of 5.5 wt%. The calculated Van ’t Hoff equation indicates a desorption temperature of 248 K for the model. Moreover, reversible hydrogen storage can be achieved at medium to low pressures, with desorption temperatures ranging from 285 K to 417 K. These results suggest that Na-Modified IG models are candidate materials for reversible hydrogen storage under near-ambient conditions.

Near-Ambient Pressure Oxidation of Silver in the Presence of Steps: Electrophilic Oxygen and Sulfur Impurities.

The oxidation of Ag crystal surfaces has recently triggered strong controversies around the presence of sulfur impurities that may catalyze reactions, such as the alkene epoxidations, especially the ethylene epoxidation. A fundamental challenge to achieve a clear understanding is the variety of procedures and setups involved as well as the particular history of each sample. Especially, for the often-used X-ray photoemission technique, product detection, or photoemission peak position overlap are problematic. Here we investigate the oxidation of the Ag(111) surface and its vicinal crystal planes simultaneously, using a curved crystal sample and in situ X-ray photoelectron spectroscopy at 1 mbar O2 near-ambient pressure conditions to further investigate surface species. The curved geometry allows a straightforward comparative analysis of the surface oxidation kinetics at different crystal facets, so as to precisely correlate the evolution of different oxygen species, namely nucleophilic and electrophilic oxygen, and the buildup of sulfur as a function of the crystal orientation. We observed that emission from both surface and bulk oxide contributes to the characteristic nucleophilic oxygen core-level peak, which arises during oxygen dosing and rapidly saturates below temperatures of 180 °C. The electrophilic oxygen peak appears later, growing at a slower but constant rate, at the expenses of the surface oxide. Electrophilic oxygen and sulfur core-levels evolve in parallel in all crystal facets, although faster and stronger at vicinal surfaces featuring B-type steps with {111} microfacets. Our study confirms the intimate connection of the electrophilic species with the formation of adsorbed SO4, and points to a higher catalytic activity of B-type stepped silver surfaces for alkene epoxidation or methane to formaldehyde conversion.

Effect of Temperature on Faradaic Efficiency and SEI Formation in Lithium Mediated Nitrogen Reduction

Lithium-mediated nitrogen reduction (Li-N2R) can be distributed and powered by renewable energy, making it a sustainable ammonia production alternative to the Haber Bosch process. While Haber Bosch is responsible for 1.3% of CO2 emissions yearly and requires centralized facilities with high temperatures and pressures, Li-N2R works at near-ambient conditions and therefore allows for decentralized production.1 First, lithium (Li+) ions electroplate as lithium metal on the working electrode. Second, the deposited lithium reacts with N2 gas to form lithium nitride (Li3N). Lastly, Li3N reacts with a proton source to form ammonia (NH3) (Figure Right).During Li-N2R, the NH3 selectivity is controlled through the mass transport of N2, Li+, and protons to the working electrode electrode (WE). The transport of these species is limited by the solid electrolyte interface (SEI), a passivation layer formed on top of the WE.2 The thickness and ratio of organic and inorganic species in the SEI change at different cycling temperatures, thus affecting the rates of transport between charge and uncharged species traveling to and from the electrode. Here, we study the impacts of temperature on FE and SEI composition in 1M LiBF4 in both diglyme (DG) and tetrahydrofuran (THF) with a 1v% ethanol (EtOH) proton source (Figure Left). Using ion chromatography (IC), nuclear magnetic resonance (NMR), and inductively coupled plasma mass spectrometry (ICP-MS) on the SEI dissolved in D2O, we quantify the SEI species formed at different cycling temperatures. Our correlation of temperature and SEI compositions to FE provide opportunities to engineer the SEI for improved Li-N2R FE and stability. 1J. W. Erisman et al., Nat. Geosci 2008. 1, 636–639 2K. Steinberg et al., Nat. Energy 2022, 8 (2), 138 Figure 1

Fluorescence of BODIPY dyes in gas phase at near-ambient conditions

Molecular fluorescence is a phenomenon that is usually observed in condensed phase. It is strongly affected by molecular interactions. The study of fluorescence spectra in gas-phase can provide a nearly ideal model for the evaluation of the intrinsic properties of fluorophores. Unfortunately, most conventional fluorophores are not volatile enough to allow for the study of their fluorescence in gas phase. Here we report very bright gas phase fluorescence of simple BODIPY dyes that can be readily observed at atmospheric pressure using conventional fluorescence instrumentation. To our knowledge, this is the first example of visible-range gas-phase fluorescence at near-ambient conditions. Evaporation of the dye in vacuum allowed us to demonstrate organic molecular electroluminescence in gas discharge excited by the electric field produced by a Tesla coil.

Experimental Investigation of Amine Regeneration for Carbon Capture through CO2 Mineralization

Summary The most common method for point-source carbon capture involves the absorption of CO2 from flue gas by amine solutions. The CO2 is then stripped from the amine solution by desorption with steam or heat. While amine solvents exhibit high CO2 absorption efficiency, their desorption process consumes a substantial amount of energy. A more energy-efficient alternative for the regeneration of the amine can be done through a mineralization process. Past studies have shown the feasibility of mineralizing captured CO2 from amine solution using calcium oxide (CaO) or other CaO-containing industrial waste. This study aims to show experimentally the extent of mineralization over time in near-ambient conditions and develop a mechanistic model. Lab-scale experiments are conducted to determine the absorption characteristics of CO2 in monoethanolamine (MEA) solutions and the extent of mineralization. We observe that pH serves as an indicator for CO2 loading in amine solutions. At high concentrations of MEA, CO2 absorption efficiency is about 0.5 mol CO2/mol MEA. Under ambient pressure and a temperature of 40°C, CaO effectively mineralizes CO2 and regenerates MEA. The CaO initially reacts with water to produce calcium hydroxide (Ca(OH)2) and subsequently reacts with dissolved CO2, forming calcium carbonate (CaCO3). Both 13C nuclear magnetic resonance (NMR) and FTIR indicate that MEA can be regenerated with an efficiency close to 69 to 98%, by comparing the carbamate and bicarbonate peaks in the 13C NMR response. A model to describe the absorption and mineralization reaction is proposed using the PHREEQC software; the pH is matched within less than 3% error. This study demonstrates that CO2 desorption from MEA solutions can occur through mineralization, converting CO2 into carbonates at low pressure and temperature with CaO. This method has lower energy consumption and results in the most stable form of CO2, making it a safer sequestration strategy than supercritical CO2 storage in reservoirs.

Local number fluctuations in ordered and disordered phases of water across temperatures: Higher-order moments and degrees of tetrahedrality.

The isothermal compressibility (i.e., related to the asymptotic number variance) of equilibrium liquid water as a function of temperature is minimal under near-ambient conditions. This anomalous non-monotonic temperature dependence is due to a balance between thermal fluctuations and the formation of tetrahedral hydrogen-bond networks. Since tetrahedrality is a many-body property, it will also influence the higher-order moments of density fluctuations, including the skewness and kurtosis. To gain a more complete picture, we examine these higher-order moments that encapsulate many-body correlations using a recently developed, advanced platform for local density fluctuations. We study an extensive set of simulated phases of water across a range of temperatures (80-1600K) with various degrees of tetrahedrality, including ice phases, equilibrium liquid water, supercritical water, and disordered nonequilibrium quenches. We find clear signatures of tetrahedrality in the higher-order moments, including the skewness and excess kurtosis, which scale for all cases with the degree of tetrahedrality. More importantly, this scaling behavior leads to non-monotonic temperature dependencies in the higher-order moments for both equilibrium and non-equilibrium phases. Specifically, under near-ambient conditions, the higher-order moments vanish most rapidly for large length scales, and the distribution quickly converges to a Gaussian in our metric. However, under non-ambient conditions, higher-order moments vanish more slowly and hence become more relevant, especially for improving information-theoretic approximations of hydrophobic solubility. The temperature non-monotonicity that we observe in the full distribution across length scales could shed light on water's nested anomalies, i.e., reveal new links between structural, dynamic, and thermodynamic anomalies.

Experimental and numerical investigations on synergistic coupling of metal hydride hydrogen storage systems with low-temperature proton exchange membrane fuel-cell

Hydrogen has emerged as a promising alternative for various energy needs, and metal hydride hydrogen systems offer significant potential due to their near-ambient working conditions and safe storage. This study presents experimental and numerical investigations on a lab-scale metal hydride fuel cell system to showcase its viability in addressing future energy demands. The experimental setup includes a 41-tube Metal Hydride (MH) reactor with an outer cooling jacket, containing 3.75 kg of La0.7Ce0.1Ca0.3Ni5. The output of the reactor is coupled to a 1 kW fuel cell, with controlled hydrogen discharge at temperatures ranging from 30 to 50 °C through numerical modelling. The study found that maintaining the reactor at 40 °C was sufficient to sustain the required bed pressure for a 1 kW fuel cell. Numerical simulations revealed that a 1 kW fuel cell operating at a current density of 0.8 A/cm2 and 50 °C rejected approximately 1.3 kW of waste heat. Moreover, 3.75 kg MH reactor could discharge hydrogen at a constant rate of 13 l/min for 36.3 min with just 125–225 W of heat input, highlighting the thermal coupling potential between these systems. The energy efficiency of the coupled MH-PEMFC system increased by 1.8 times to reach 49% at 50 °C. Additionally, the waste heat generated proved sufficient to provide the required endothermic heat to multiple MH reactors, with a single reactor utilizing only 16.3% of the total waste heat. This integrated system demonstrates promising efficiency and sustainability for future energy applications.