Nickel-cobalt sulfide (NCS) has been widely studied as an electrode material for supercapacitors due to its high theoretical specific capacity. However, its slow diffusion kinetics hindered its practical applications. In this work, hierarchical Cu-doped (Ni,Co)3S4 nanoflowers were prepared with microwave assisted heating and Cu addition to address this issue. Through comprehensive experimental investigation and first-principles calculation, microwave radiations were found to accelerate and alter the precipitation kinetics so that Cu doping was realized in (Ni,Co)3S4 lattice and that Cu9S5 was obtained. Meanwhile, Cu ions enhanced the hierarchy of nanoflowers, further promoting the diffusion kinetics. First-principles calculation revealed that Cu doping promoted the adsorption activity of Co atoms and suppressed the Ni-S, Co-S Coulomb interactions, which agreed with the exsitu XPS analysis in charge-discharge cycles. High specific capacity (259.6 mAh & sdot;g- 1 at 1 A g- 1) and good rate performance (82.2% at 20 A g- 1) were achieved with a Cu-doped NCS electrode. This work demonstrated an efficient and mild route for the fabrication of hierarchical NCS for supercapacitor applications and provided a comprehensive view of elemental doping effect on NCS supercapacitors. It shed new light on the microwave assisted heating in nanomaterials fabrication and the scaled production of high performance NCS supercapacitors.

Magnesium hydride (MgH2) is a highly promising solid-state hydrogen storage material, but its high dehydrogenation temperature and slow kinetics limit its practical application. This study investigates the enhancing effect of nano-sized LiNbO3 (n-LNO) as a catalyst on the hydrogen storage performance of MgH2. Highly dispersed n-LNO nanoparticles (40-60 nm) were successfully prepared via an improved polymer precursor method, exhibiting a significantly larger specific surface area than micro-sized LiNbO3 (u-LNO, 0.8-1 mu m) synthesized by the traditional hydrothermal method. Results showed that the onset dehydrogenation temperature (216 degrees C) and peak dehydrogenation temperature (250 degrees C) of MgH2 doped with 7 wt% n-LNO were reduced by 39 degrees C and 72 degrees C, respectively, compared to pristine MgH2 (255 degrees C, 322 degrees C). Compare to that of the u-LNO, though the onset dehydrogenation temperatures for the micro-and nano-sized catalysts were similar, their desorption termination temperatures and isothermal dehydrogenation rates differed significantly. The high dispersion of n-LNO on the MgH2 surface provided abundant active sites for dehydrogenation. The isothermal dehydrogenation test showed that it could release 6.18 wt% of hydrogen within 5 min at 300 degrees C, and its apparent dehydrogenation activation energy (91.37 kJ center dot mol-1) was significantly reduced by 77.63 kJ center dot mol-1 compared to ball-milled pristine MgH2. XPS analysis revealed the dynamic catalytic mechanism of n-LNO: the reversible oxidation-reduction reactions of Nb5+/Nb2+ occur on its surface, and Nb2+ as a key active species significantly promotes the dissociation and diffusion of hydrogen.

MgH2 is a hydrogen storage material with high hydrogen absorption/release temperatures and poor kinetics. Although a large number of catalysts capable of optimizing the performance of MgH2 have been developed in recent years, there are relatively few studies focus on its size effect. In this work, TiO2 particles with the similar morphology but different sizes were synthesized. It shows that reducing particle size within a certain range (from 1.3 mu m to 60 nm) can dramatically enhance the catalytic effect of TiO2 on MgH2. However, when the catalyst size reduces from 60 to 25 nm, due to the severe agglomeration of nanoparticles, there is a little improvement in the dehydrogenation temperature, but an obvious improvement in dynamics. It can be seen in solid-state catalytic systems, merely considering particle size while ignoring the problem of agglomeration and dispersion form of the catalyst in the matrix cannot achieve the best catalytic effect.

To address the high viscosity and strong acidity of conventional iron-based ionic liquids, a series of mixed solutions were prepared by blending FeCl3/[Nbmm]Br with low-viscosity, basic organic solvents. Quantum chemical calculations, including interaction energy, energy decomposition, interaction region indicator, and Atoms-in-Molecules analyses, were employed to investigate the molecular interactions between H2S and 11 industrially relevant solvents. Based on viscosity and H2S affinity, seven candidate solvents were identified. Among them, sulfolane demonstrated the highest stability when combined with FeCl3/[Nbmm]Br, which can be attributed to its weak Lewis basicity arising from the rigid four-membered ring and the steric hindrance of the electron-rich sulfone oxygen atoms. Response surface methodology was applied to optimize the absorption conditions, resulting in an optimal anion-to-cation molar ratio of 0.8 mol & centerdot;mol-1, a solvent-to-IL ratio of 0.2 mL & centerdot;mL-1, and a temperature of 26 degrees C. Under these conditions, the H2S loading reached 0.0173 mol & centerdot;kg-1-comparable to that of pure FeCl3/[Nbmm]Br-while the viscosity was markedly reduced from 2749.21 to 35.34 mPa & centerdot;s. Quantum chemical calculations and experimental studies revealed that the inclusion of weakly Lewis basic sulfolane reduces Fe-Cl interactions and alleviates the electron deficiency at the iron center, thereby lowering the cation's electrostatic potential and moderating acidity.

MgH2 is a promising solid hydrogen storage material, but its commercial application is limited by the poor de-/ hydriding kinetics. The commonly used modification method involves first prepare the catalyst and then ball milling it with MgH2. Herein, a composite of MgH2 with in situ carbon-supported catalyst was prepared via flexible solid reaction based on cost-effective metal carbonates as precursors. Uniformly distributed Ni nano-particles (2-5 nm) as the actively catalytic sites are attached through in situ carbon capsule to construct an efficient catalytic network. Such well-designed structure enables MgH2 with high hydrogenation capacity (4.7 wt % at 40 degrees C) and low dehydrogenation temperature (start as low as 180 degrees C). Further mechanism study reveals the nano-Mg2Ni with stronger hydrogen pump effect exhibits remarkable transmittability of H ions and the optimized transport path by carbon capsule layer enhances the electrons transmittability, which eventually accelerates the redox reaction process of de-/hydriding. This work not only significantly improves the hydrogen storage performance of MgH2 through a one-step modification method, but also provides new insights into the catalytic mechanism of hydrogen storage materials from the perspective of ions/electrons transmittability.

MXene-based electrode materials for supercapacitors are hindered in large-scale applications by inherent drawbacks such as severe restacking, susceptibility to oxidation, and limited energy density. To overcome these limitations, a multi-component synergistic design strategy is proposed. In this work, nickel phthalocyanine (NiPc) molecular complexes are anchored onto MoS2 wrapped on MXene sheets, constructing a three-dimensional (3D) hierarchical heterostructure electrode material denoted as NiPc@MoS2/Ti3C2Tx. MXene acts as a conductive framework, providing efficient electron transport pathways. The intercalation of MoS2 effectively suppresses MXene restacking while introducing abundant electrochemically active sites. Meanwhile, NiPc complexes function as molecular pillars to expand the interlayer spacing, donate electrons to induce a partial phase transition of MoS2 (from 2H to 1T phase), and provide reversible redox-active centers. Density functional theory (DFT) calculations confirm that the introduction of NiPc thermodynamically and electronically facilitates the phase transition from 2H to 1T in MoS2. Consequently, the composite exhibits a substantial specific capacitance of 351.4 F g−1 at a current density of 0.5 A g−1, while maintaining approximately 82.1% of its capacitance at 10 A g−1, thereby demonstrating exceptional rate capability. An asymmetric supercapacitor assembled with this material exhibits an energy density of 33.89 Wh kg−1 at a power density of 800 W kg−1 and maintains 88% capacity after 10,000 cycles. These results demonstrate the strong potential of NiPc@MoS2/Ti3C2Tx for next-generation supercapacitors.

Ammonia, with a hydrogen content of 17.6 wt%, is a promising carbon-free hydrogen carrier, yet its decomposition is kinetically limited by the recombinative desorption of surface nitrogen species. Herein, a series of Cs and Ce promoted Ru/γ-Al2O3 catalysts (Ru, RuCs, RuCe, and RuCsCe) were employed for efficient NH3 decomposition in a packed-bed dielectric barrier discharge (DBD) plasma reactor. The structure-activity relationship was established through systematic characterization (XRD, SEM, TEM, XPS, H2-TPR, NH3-TPD, CO2-TPD, and N2-TPD) combined with DFT calculations of adsorption energies, reaction barriers, Bader charges, and density of states. Among these catalysts, the co-promoted RuCsCe delivered the best performance over 150-400 °C, gas hourly space velocities of 12,000–48,000 h−1, and discharge powers of 10-80 W, achieving over 95% NH3 conversion at 300 °C and 80 W and a GHSV of 12,000 h−1, retaining 68.6% conversion even at 150 °C, and maintaining approximately 96% conversion over 50 h of continuous operation. Its superiority originates from the complementary functions of the two promoters: Cs donates electrons to Ru and moderates the adsorption of N* (−0.58 eV) and N2 (−0.71 eV), whereas interfacial CeOx traps H atoms and stabilizes dehydrogenation transition states. This electronic-interfacial synergy flattens the reaction energy landscape and reduces the rate-limiting reaction barrier from 1.31 eV on Ru to 1.03 eV on RuCsCe. Electrical diagnostics based on Q-U Lissajous plots and voltage-current waveforms further confirmed that the catalyst packings retain surface-discharge-dominated DBD behavior while intensifying filamentary micro-discharges. This work provides a practical promoter-design strategy for efficient plasma-catalytic hydrogen production from ammonia.

ZrCo-based alloys are regarded as highly potential hydrogen isotope storage materials in the field of nuclear fusion due to their high hydrogen storage capacity and excellent de-/hydrogenation kinetics. However, their practical applications are limited by the attenuation of activity caused by hydrogen-induced disproportionation reactions and oxygen-induced poisoning. Although Zr0.8Nb0.2Co0.6Cu0.2Ni0.2 alloy was obtained through multiple alloying, which overcomes the hydrogen-induced disproportionation problem, but the latter remains to be resolved. Therefore, this study deeply explored the microstructure evolution during the kinetic deactivation and thermodynamic disproportionation of Zr0.8Nb0.2Co0.6Cu0.2Ni0.2 alloy caused by oxygen. A novel concept of oxygen-induced disproportionation is discovered and proposed, corresponding to the reaction from orthorhombic ZrCo phase to cubic ZrCo and Zr7Ni10 phases. Detailed theoretical calculations and in-situ characterizations reveal that the migration of Zr atoms triggered by the intercalation/de-intercalation of oxygen atoms dominates such capacity fading. Thus, by establishing the "time-temperature-performance" spectrum, the most suitable recovery condition for possibly avoiding the oxygen-induced disproportionation was determined, providing a theoretical basis for the optimization of the anti-poisoning performance of ZrCo-based hydrogen storage alloys.

The study investigated the influence of Ce alloying and cold rolling on the activation behavior of V70Ti10Cr20-based alloys. The activation conditions of single cold rolled (V70Ti10Cr20-0.3) and single Ce replaced (V70Ti10Cr20Ce1) samples were reduced from the original two heat treatments to one heat treatment, and the incubation time was about 105 min. Unexpectedly, the two modification methods produce excellent synergistic effects that the co-modified sample (V70Ti10Cr20Ce1-0.5) was activated at room temperature (25°C) without incubation period, and reached saturation capacity (4wt

Electrochemical ammonia synthesis via nitrate reduction reaction (NO3RR) offers a sustainable solution for mitigating nitrate pollution while recovering valuable nitrogen resources. Conventional flow-by/batch systems suffer from slow kinetics and low current efficiency due to a thick boundary layer at the electrode surface, which impairs NO3RR activity and selectivity. This study introduces a novel flow-through configuration employing a micron-porous CuO-Co3O4 composite membrane electrode for enhanced NO3RR. Computational fluid dynamics simulations revealed a significantly thinner boundary layer (similar to 10 mu m) in the flow-through mode compared to flow-by (>120 mu m). Consequently, the flow-through mode exhibited a seven-fold increase in NO3RR kinetics, boosting the ammonia Faradaic efficiency (FE) from 7.2 % to 79.8 %. Optimization of the Co3O4 membrane electrode, addressing parameters of Cu/Co loading and pore size, further enhanced performance. This achieved high ammonia selectivity and FE (up to 95.7 % and 88.1 %, respectively) across a broad nitrate concentration range (0.02-1.0 g N L-1). Mechanistic investigations, integrating scavenger-quenching experiments, electrochemical analyses, and electron paramagnetic resonance spectroscopy demonstrated that ammonia synthesis primarily followed the dominance of the direct electron transfer (DET) between the flow-through cathode and nitrate/nitrite, while hydrogen species (H*) served an auxiliary function. These results underscore the effectiveness of the flow-through membrane electrode configuration in facilitating efficient electrochemical ammonia synthesis, offering valuable insights for the advancement of electrochemical technologies for pollution control and resource recovery.

Vanadium-based alloys, regarded as one of the most promising high-capacity hydrogen storage alloys, have garnered substantial attention and research from scholars. This work systematically reviews the research progress of V-based hydrogen storage alloys over the past 20 years and summarizes all modification works into three aspects: Ternary component design, doping element analysis and process optimization, which can help researchers effectively grasp the core content of the complex literature. In order to solve the pain points of the lack of connection between the composition, microstructure and hydrogen storage properties of different V-based hydrogen storage alloys. It is divided into V-Ti-Mn, V-Ti-Fe and V-Ti-Cr, considering the factors of composition and performance defects, and the subsequent modification measures are proposed for each system. Especially, we proposed a new method to optimize the crystal form, cell parameters and phase stability of the alloy by coordinated modulation of Ti/Cr ratio and V content to better develop the V-Ti-Cr alloys with higher performance for practical application.

Wadsley-Roth phase niobates demonstrate significant Li+-storage advantages. Even though their Nb5+ can fully transform into Nb4+ during lithiation process, however, only partial Nb4+ can further convert to Nb3+, leading to much lower practical capacities than the theoretical values according to the two-electron transfer per Nb5+. The specific mechanism to improve their conversion ratio of Nb4+ to Nb3+ during lithiation process has rarely been reported so far. Herein, the ultrafine oxygen-deficient Cu2Nb34O87-x nanoparticles are closely connected by the N-doped carbon-based 3D conductive framework to form a cloud-like Cu2Nb34O87-x/N-doped carbon composite (denoted as VU-CNO-NC) with nanoaggregate structure and porous structure. Based on density functional theory (DFT) calculations and ex situ X-ray photoelectron spectrometer (XPS), the oxygen vacancies in VU-CNO-NC can catalyze the conversion of Nb4+ to Nb3+ during lithiation process, which significantly enhance the conversion ratio of Nb4+ to Nb3+ to generate much higher capacity. This effect of oxygen vacancies has rarely been reported so far. Moreover, the oxygen vacancies, ultrafine primary nanoparticles, 3D conductive framework, porous structure, and nanoaggregate structure synergistically endow VU-CNO-NC with fast Li+-storage kinetics and highly stable structure. Consequently, VU-CNO-NC not only shows high capacity (287 mAh g-1 after 500 cycles at 1 C and 181 mAh g-1 after 1000 cycles at 10 C) and excellent rate performance as anode material of lithium-ion batteries, but also endows hybrid lithium-ion capacitor with high energy density (126 Wh kg-1 at 175 W kg-1) and remarkable capacity retention (87.3 % after 9000 cycles at 2 A g-1), demonstrating great application prospect.

In recent years, a large number of studies have shown that amine based water-lean absorbents formed by amines and organic solvents exhibit high capture efficiency and low regeneration energy consumption in CO2 capture. However, there is a lack of research that combines molecular level structure with macroscopic properties. In order to optimize the performance of amine based homogeneous water-lean absorbents by utilizing the properties of organic solvents, and to explore the correlation between the macroscopic properties of the absorbents (CO2 capacity, removal efficiency, regeneration rate, regeneration efficiency, etc.) and the molecular structure of the absorbent components. We used experiments and molecular dynamics to study the linear terminal diamine DMEDA and non-proton polar solvent (DMF, DMPA, NMP, SFL, DMSO) system. It was found that the absorption and desorption performance of water-lean solvents was higher than that of aqueous solutions 30 wt% MEA and 30 wt% DMEDA, among which EFH with DMF as the solvent has better comprehensive performance. The molecular dynamics simulation was built to describe the solution structures of these absorbents. Through RDF calculations, the unique behavior of DMEDA in non-proton polar solvent was revealed on molecular level, it was found that organic solvents tend to aggregate with DMEDA molecules to form large molecular clusters, while CO2 molecules may diffuse through ordered pore structures, resulting in a significant improvement in the capture performance. And it was found that there is a quantitative relationship between the intensity of intermolecular interaction between DMEDA and CO2 and the removal efficiency change in DMEDA water-lean absorbents. A functional relationship was fitted, and a preliminary and rapid method for determining capture performance through molecular dynamics was proposed.

Supercapacitors are electrical energy storage devices renowned for their high power density and long cycle life. However, their low energy density has limited their broader application, particularly in electric vehicles. Carbon nanomaterials, including carbon nanotubes and graphene, are among the most promising electrode materials for enhancing energy density due to their unique structures, excellent electrical, mechanical, and thermal properties, large specific surface area, and chemical inertness in both acidic and alkaline environments. Significant progress has been made in the development of high-performance carbon-based supercapacitors. In this Review, we begin by exploring the origin and mechanisms of charge storage in supercapacitors. We then summarize the current advancements in enhancing the capacitive performance. The theory and primary strategies for designing high-performance supercapacitors are discussed to provide guidance on electrode material selection and design. Finally, future research directions and perspectives are presented with the aim of advancing the development of efficient carbon-based supercapacitors.

Magnesium hydride (MgH2) has shown extensive applications in energy storage, medical therapy, agricultural technology and environmental health in recent years. However, these attractive prospects mainly remain at the research or proof-of-concept stage due to the high cost of MgH2 (>500 $ kg(-1)), which limits their commercialization. In fact, the cost of the raw materials for MgH2 (similar to 6 $ kg(-1) for H-2, similar to 4 $ kg(-1) for Mg) is not high, but the intricate synthesis process, including lengthy synthesis period, limited production capacity as well as stringent synthesis equipment, makes it challenging to reduce the cost of MgH2. It clearly illustrates that resolving problems in the synthesis of MgH2 becomes essential for unlocking its potential for practical application. In this work, a comprehensive summary of diverse MgH2 synthesis methods is presented. To better reflect the merits and shortcomings, we classify the existing synthesis techniques into six categories from the perspective of thermodynamic and kinetic intrinsic reaction mechanism. Moreover, the in-depth analysis based on their reaction mechanisms was adopt to achieve better improvement. Finally, to bridge the lab-to-plant gap, we established a techno-economic framework encompassing cost, production capacity, production period, safety assessment, and hydrogen storage performance, and proposed viable production enhancement pathways for magnesium hydride synthesis.

Hydrolytic hydrogen production materials, particularly MgH2, have garnered extensive attention for their high hydrogen storage capacity and environmental benefits. Highly active MgH2 has better hydrolysis properties, but is also more prone to oxidative deactivation during storage, which has a great impact on its practical application. To address this contradiction between hydrolysis activity and storage stability, we developed a polymer coated cream-type MgH2. The novel designed MgH2 cream maintains air stability while enabling controllable hydrolysis upon mixing with polyethylene glycol, achieving a final hydrogen yield of 1440 mL/g, with only an 8.2% reduction after 12 h of air exposure. Furthermore, the MgH2 cream simplifies storage, enhances safety, and supports diverse applications, which provides a practical and innovative pathway for advancing hydrolytic hydrogen production technologies.

MgH2 is a promising solid-state hydrogen storage material; one of the limitations of its scale-application is the slow rate of hydrogen uptake and release. The addition of catalyst to improve the kinetics of MgH2 has achieved remarkable results. However, these studies require high-speed ball milling (400–500 rpm) to achieve the combination of MgH2 and catalyst, and such harsh processing conditions are difficult to achieve in industrial production. In this work, the catalyst and MgH2 were efficiently combined at lower milling speed (300 rpm) by introducing tetrahydrofuran C4H8O (THF) as an auxiliary agent. Moreover, milling with THF promotes the nano-crystallization of MgH2, which further improves its performance. Results show that THF-assisted MgH2 absorbed 6.1 wt

Lower regeneration energy and superior cyclic capacity have enabled biphasic absorbents great potential in the area of flue gas CO2capture. The liquid film mass transfer coefficient(kL) is a vital parameter in the development of absorbents with efficient CO2 absorption mass transfer performance, while the phase separation behavior of biphasic solutions could be an essential factor for the absorption mass transfer and the stability of absorber. However, systemic kinetic research towards biphasic absorbents, especially the impact of phase separation behavior, is limited. In this study, a typical amide-based biphasic absorbent diethylenetriamine(DETA)/diethanolamine(DEA)/N, N-dimethylacetamide(DMAC) which has achieved great reduction in regeneration energy, was selected as the subject of kinetic investigation in a wetted wall column. The CO2 overall mass transfer coefficient(KG) of DETA/DEA/DMAC exceeded other biphasic solvents, blended amine solution, and 40% K2CO3 solution, with 3 times that of 40% K2CO3 solution. Moreover, various operational conditions including absorption temperature, gas flow rate, and water content of solution were taken into account to build a multiple-condition kinetic mechanism to offer guidance for biphasic absorbents. Furthermore, phase separation behavior was revealed as the main blame for the deterioration in the liquid film chemical mass transfer process of biphasic solvents in the CO2 absorption process, resulting in the kL of DETA/DEA/DMAC before phase separation decreased by 75.3% at the phase separation stage. Therefore, it is crucial to ensure that the CO2 loading of the solution entering absorber is lower than the phase separation point in applications. After phase separation, DETA/DEA/DMAC split into the organic and aqueous phases, the kL of the aqueous phase gradually exceeded that of the organic phase as CO2 loading increased for its higher chemical enhancement factor(E).

Among V (vanadium)-based hydrogen storage alloys, high-V alloys show significant advantages and prospects. However, the small change of V content will have a great impact on the hydrogen storage performances, so it is of great significance to accurately optimize the V content. Herein, the structure and hydrogen storage properties of V75-XTi5+XCr20 (x = 0, 5, 10) alloys were studied, and the underlying micromechanisms were revealed. It was observed that an increase in the Ti/V ratio leads to a rise in the content of the second phase enriched with Ti, yet even a small amount of the Ti-rich phase can significantly enhance activation performance. The hydrogen desorption plateau exhibits a decreasing trend with the increasing presence of the Ti-rich phase. The results indicate that the optimal comprehensive hydrogen storage performance is achieved when the V content is 70 atom %, exhibiting a suitable plateau pressure of 2.84 bar and a high hydrogen storage capacity of 2.40 wt % at 20 degrees C and 3.00 wt % at 200 degrees C. Furthermore, after 50 cycles, the capacity retention rate remains as high as 96.4 atom %. This performance establishes a solid foundation for future engineering applications of high-capacity hydrogen storage materials.