Reaction Kinetics Research Articles

Orbital interactions and high spin states: Unlocking the potential of Co-Single-Atom catalysts for Li-S batteries

Single-atom catalysts (SACs) have been widely utilized in lithium-sulfur (Li-S) batteries. However, their sluggish reaction kinetics and serious shuttling effects remain major challenges. Current research on SACs focuses on adjusting their coordination structure to bolster the adsorption and conversion of polysulfides while overlooking their enhancement through modulation of the electronic structure of the metal centers. This study proposes a novel approach for synthesizing nitrogen-doped Co-SACs (Co-SAC@NC). Theoretical calculations and experimental results indicate that nitrogen doping leads to a high Fermi energy level within Co-SAC@NC, signifying an elevated average energy of the electrons. This elevation results in significant splitting and lifting of degeneracy among d-orbitals in Co metal, which ultimately leads to a high-spin configuration. This configuration enhances the orbital interactions between the polysulfides and the catalyst, causing a decrease in the energy barrier and fast conversion from polysulfides to lithium sulfide. Thus, it improves the polysulfide kinetics. As a result, the batteries with the Co-SAC@NC modified separator exhibit a remarkable initial discharge capacity of 1465 mAh g−1 at 0.1C and excellent rate performance (736 mAh g−1 at 4C), outperforming most Co-SAC-based Li-S batteries.

Facile hydrothermal synthesis of ZnIn2S4/TiO2 nanosheets for promoted hydrogen evolution reaction

The current study was conducted by introducing a narrow bandgap semiconductor, ZnIn2S4, with the goal of addressing the inefficiency of hydrolysis dissociation and the limited visible light absorption capacity faced by TiO2 as a hydrogen evolution reaction (HER) catalyst due to its low conduction band position and wide bandgap. Using a one-step hydrothermal process, ZnIn2S4 nanosheet/TiO2 nanorod heterostructures were built on nickel foam substrates. The nanosheet structure of ZnIn2S4 is shaped like a flower, which greatly increased the roughness of the TiO2 surface and revealed additional active sites. The ZnIn2S4/TiO2 heterostructure demonstrates quick reaction kinetics and effective electron transport capability, as demonstrated by the electrochemical test results. An overpotential of just 195 mV is required to obtain a current density of 10 mA cm−2. In addition, the overpotential is further decreased to 160 mV under simulated solar radiation. Furthermore, ZnIn2S4 addition minimizes the free energy of hydrogen adsorption on the TiO2 surface and optimizes the position of its Fermi energy level, improving the usage of photogenerated carriers, according to density functional theory (DFT) calculations. This work validates the prospective use of ZnIn2S4/TiO2 heterostructures in photoelectrocatalysis and offers a fresh viewpoint for developing high-performance HER catalysts.

Ultrafast and stable molten salt aluminum organic batteries

Aluminum-organic batteries (AIBs) have gained significant popularity for large-scale energy storage due to their abundance of aluminum reserves, cost-effectiveness, and environmental friendliness. However, the current aluminum-organic batteries primarily relied on ionic liquid electrolytes suffer from slow reaction kinetics and limited cycle life. Herein, we report a novel and efficient aluminum-organic battery that addresses these limitations by utilizing a molten salt electrolyte and designing a strongly interacting organic cathode. By enhancing π-π stacking interactions, we induced a transition in commercial PTCDA (Perylene-3,4,9,10-tetracarboxylic dianhydride) molecules from the β-phase to the highly interactive α-phase, known as PA450. This transformation not only stabilizes the structure of the PA450 electrode, preventing dissolution in the molten salt electrolyte, but also significantly improves electron conductivity. The Al||PA450 molten salt battery demonstrates exceptional electrochemical performance, exhibiting a high reversible capacity of 135 mAh g–1 and outstanding cyclability for up to 2000 cycles at 10 A g−1. Additionally, the structural rearrangement and ion transport properties induced by the co-intercalation of Al3+ and AlCl2+ were studied are investigated. This work provides deep insights into the unique characteristics of organic materials for ultrafast energy storage in molten salt electrolytes.

Regioselective analysis of heat-induced conformational changes of β-lactoglobulin by quantitative liquid chromatography–mass spectrometry analysis of chemical labeling kinetics

β-Lactoglobulin is a main allergen in cow's milk; its allergenicity is strongly impacted by processing. To understand heat-induced epitope-specific effects, the present study analyzed regiospecific conformational changes of heated native β-lactoglobulin variant A (BLG-A). Complementary fluorescence spectroscopy methods indicated two denaturation phases comprising minor sequential conformational changes (25–75 °C) and complete transitions (80–90 °C). Regioselective conformational changes of BLG-A in the native state (25 °C), sequential (70 °C) and complete transition (90 °C) were determined by quantitative liquid chromatography–mass spectrometry analysis of chemical labeling kinetics covering 14 lysine residues and the N-terminus. Conformational changes in two phases were observed for N-terminus, K8 (both N-terminal chain), K60 (β-sheet C), K75 (β-sheet D), K77 (DE loop), K83 (β-sheet E), K100 and K101 (FG loop). The residues K14 (β-sheet A1), K47 (β-sheet B), K69, K70 (both β-sheet D), and K91 (β-sheet F) were not involved in conformational changes.

Fabrication of a reusable carbon quantum dots (CQDs) modified nanocomposite with enhanced visible light photocatalytic activity

In awareness of industrial dye wastewater, carbon quantum dots (CQDs) and cobalt zinc ferrite (CZF) nanocomposites were synthesised for the making of carbon quantum dots coated cobalt zinc ferrite (CZF@CQDs) nanophotocatalyst using oxidative polymerization reaction. The results of TEM, zeta potential value, and FTIR confirm highly dispersed 1–4 nm particles with the − 45.7 mV carboxylic functionalized surface of CQDs. The results of the synthesised CZF@CQDs photocatalyst showed an average particle size of ~ 15 nm according to TEM, SEM, and XRD. The photocatalyst showed a 1.20 eV band gap, which followed the perfect visible light irradiation. TGA and DTA revealed the good thermal stability of the nanophotocatalyst. VSM was carried out, and the saturation magnetisations for CZF and CZF@CQDs were 42.44 and 36.14 emu/g, respectively. A multipoint study determined the BET-specific surface area of the CZF@CQDs photocatalyst to be 149.87 m2/g. Under visible light irradiation, the final CZF@CQDs nanophotocatalyst demonstrated remarkable efficiency (~ 95% within 25 min) in the photocatalytic destruction of Reactive Blue 222 (RB 222) and Reactive Yellow 145 (RY 145) dyes, as well as mechanical stability and recyclability. Even after the recycling of the degradation study, the nanophotocatalyst efficiency (~ 82%, 7th cycles) was predominantly maintained. The effects of several parameters were also investigated, including initial dye concentration, nanophotocatalyst concentration, CQD content, initial pH of the dye solution, and reaction kinetics. Degradation study data follow the first-order reaction rate (R2 > 0.93). Finally, a simple and low-cost synthesis approach, rapid degradation, and outstanding stability of the CQD-coated CZF nanophotocatalyst should make it a potential photocatalyst for dye wastewater treatment.

Co–FeOOH thin nanosheets derived from 2D ZIF-L for efficient oxygen evolution reaction

The complicated reaction pathway and slow electron-transfer kinetics of the oxygen evolution reaction (OER) have been identified as a critical bottleneck that restricts the overall performance of electrochemical water splitting. Metal oxyhydroxides have emerged as viable alternative catalysts as compared to the precious metal-based commercial benchmarks. Yet, the activity may be compromised by the instability of the layered structures. Herein, a simple two-step method is developed for the synthesis of Co–FeOOH electrocatalysts by thermal treatment of cobalt-containing zeolitic imidazolate framework (ZIF-L) deposited on the skeleton of NF (nickel foam) in the presence of FeSO4 and urea. Co–FeOOH/NF, the thin nanosheet arrays exhibit a high specific surface area and high hydrophobicity. The addition of Co regulates the electronic environment around the Fe center, which optimizes the adsorption energy of intermediates and enhances the inherent OER activity of active sites. The Co–FeOOH nanoarrays show excellent OER performance and 99.7% Faradaic efficiency (FE). At current densities of 10 and 100 mA cm−2, there is a low overpotential of 208 and 249 mV, respectively at 1 M KOH. This kind of synthesis method will provide a promising approach for the construction of catalysts featuring stable structures for alkaline water oxidation.

Probing Electrocatalytic Synergy in Graphene/MoS2/Nickel Networks for Water Splitting through a Combined Experimental and Theoretical Lens.

The development of low-cost and active electrocatalysts signifies an important effort toward accelerating economical water electrolysis and overcoming the sluggish hydrogen or oxygen evolution reaction (HER or OER) kinetics. Herein, we report a scalable and rapid synthesis of inexpensive Ni and MoS2 electrocatalysts on N-doped graphene/carbon cloth substrate to address these challenges. Mesoporous N-doped graphene is synthesized by using electrochemical polymerization of polyaniline (PANI), followed by a rapid one-step photothermal pyrolysis process. The N-doped graphene/carbon cloth substrate improves the interconnection between the electrocatalyst and substrate. Consequently, Ni species deposited on an N-doped graphene OER electrocatalyst shows a low Tafel slope value of 35 mV/decade at an overpotential of 130 mV at 10 mA/cm2 current density in 1 M KOH electrolytes. In addition, Ni-doped MoS2 on N-doped graphene HER electrocatalyst shows Tafel slopes of 37 and 42 mV/decade and overpotentials of 159 and 175 mV, respectively, in acidic and alkaline electrolytes at 10 mA/cm2 current density. Both these values are lower than recently reported nonplatinum-group-metal-based OER and HER electrocatalysts. These excellent electrochemical performances are due to the high electrochemical surface area, a porous structure that improves the charge transfer between electrode and electrolytes, and the synergistic effect between the substrate and electrocatalyst. Raman spectroscopy, X-ray photoelectron spectroscopy, and density functional theory (DFT) calculations demonstrate that the Ni hydroxide species and Ni-doped MoS2 edge sites serve as active sites for OER and HER, respectively. Finally, we also evaluate the performance of the HER electrocatalyst in commercial alkaline electrolyzers.

ZnMn2(PO4)2·nH2O: An H2O-Imbedding-Activated Cathode for Robust Aqueous Zinc-Ion Batteries.

Component modulation endows Mn-based electrodes with prominent energy storage properties due to their adjustable crystal structure characteristics. Herein, ZnMn2(PO4)2·nH2O (ZMP·nH2O) was obtained by a hydration reaction from ZnMn2(PO4)2 (ZMP) during an electrode-aging evolution. Benefiting from the introduction of lattice H2O molecules into the ZMP structure, the ion transmission path has been expanded along with the extended d-spacing, which will further facilitate the ZMP → ZMP·nH2O phase evolution and electrochemical reaction kinetics. Meanwhile, the hydrogen bond can be generated between H2O and O in PO43-, which strengthens the structure stability of ZMP·nH2O and lowers the conversion barrier from ZMP to ZMP·4H2O during the Zn2+ uptake/removal process. Thereof, ZMP·nH2O delivers enhanced electrochemical reaction kinetics with robust structure tolerance (106.52 mA h g-1 at 100 mA g-1 over 620 cycles). This high-energy aqueous Zn||ZMP·nH2O battery provides a facile strategy for engineering and exploration of high-performance ZIBs to realize the practical application of Mn-based cathodes.

Enhanced Electrocatalysis on Copper Nanostructures: Role of the Oxidation State in Sulfite Oxidation.

The influence of surface morphology and the oxidation state on the electrocatalytic activity of nanostructured electrodes is well recognized, yet disentangling their individual roles in specific reactions remains challenging. Here, we investigated the electrooxidation of sulfite ions in an alkaline environment using cyclic voltammetry on copper oxide nanostructured electrodes with different oxidation states and morphologies but with similar active areas. To this aim, we synthesized nanostructured Cu films made of nanoparticles or nanorods on top of glassy carbon electrodes. Our findings showed an enhanced sensitivity and a lower detection threshold when utilizing Cu(I) over Cu(II). Density functional theory-based thermochemical analysis revealed the underlying oxidation mechanism, indicating that while the energy gain associated with the process is comparable for both oxide surfaces, the desorption energy barrier for the resulting sulfate molecules is three times higher on Cu(II). This becomes the limiting step of the reaction kinetics and diminishes the overall electrooxidation efficiency. Our proposed mechanism relies on the tautomerization of hydroxyl groups confined on the surface of Cu-based electrodes. This mechanism might be applicable to electrochemical reactions involving other sulfur compounds that hold technological significance.

Experimental and chemical kinetic analysis to evaluate CO2 dilution on laminar combustion characteristics of C2H5OH/air blends under normal pressure

Based on a constant volume combustion system, the effect of dilution ratio changes on the laminar combustion characteristics of C2H5OH/air mixture was studied under an initial pressure of 1 bar, initial temperatures of 370 K, 400 K, 450 K, and equivalence ratios of 0.7-1.4. A chemical kinetic mechanism for ethanol-carbon dioxide was established, and the combined physical and chemical effects of carbon dioxide were separated. An independent parameter control method was proposed, introducing virtual species FN2, ICO2, FCO2, and KCO2, to isolate the dilution effect, thermal effect, direct reaction effect, third-body effect, and transport effect. Simulation analysis using the modified chemical kinetic mechanism revealed that various impacts of CO2 reduce the peak progress rate and sensitivity coefficient of key elementary reactions. Furthermore, the dilution effect of CO2 has the greatest influence on the sensitivity coefficients and net progress rates of important elementary reactions. Based on the results of the chemical kinetic simulations, a new global reaction pathway analysis method was created, overcoming the limitations of the Chemkin-pro method. The decomposition pathway of C2H5OH throughout the combustion process was calculated as C2H5OH → SC2H4OH → CH3CHO → CH3CO → CH3 → CH2O → HCO → CO → CO2. Changes in initial temperature and dilution ratio do not alter the main decomposition pathway of C2H5OH. Detailed chemical kinetics and free radical behavior analysis indicate that the LBV of the C2H5OH/CO2/air blends has a linear correlation with [H+O+OH]max.

Ba promoter effect on cobalt-catalyzed ammonia decomposition kinetics: A theoretical analysis

Ammonia decomposition is a key reaction in the context of hydrogen storage, transport, and release. This study combines density functional theory (DFT) calculations with microkinetic modeling to address the promotion mechanism of Ba species for ammonia decomposition on Co catalysts. The modified adsorption properties of Co upon the addition of metallic Ba or BaO suggest that the promoters play a role in alleviating the competitive adsorption of H. Calculating the full reaction pathway of ammonia decomposition shows that limiting the investigation to the N–N association step, as done previously, overlooks the effect of the promoter on the energy barriers of the NHx dehydrogenation steps. Challenges of modeling the ammonia decomposition reaction are addressed by understanding that the NH2 intermediate is stabilized on the step sites rather than the terrace sites. When the effect of H-coverage on the adsorption of NH3 is not considered in the microkinetic simulations, the results conflict with the experiments. However, accounting for the effect of H-coverage, as performed here, shows that BaO-doped Co has higher rates than pristine Co and Ba-doped Co at the reaction temperature of 723.15 K. When H is adsorbed on the Ba-doped Co, the adsorption of ammonia becomes significantly endergonic, which makes the rates relatively slow. The superiority of the BaO-promoted catalyst is attributed to a lower energy for the transition state of the rate-determining step, coupled with a reduced impact of the hydrogen coverage on weakening the ammonia adsorption. The kinetic analysis of the influence of Ba and BaO on the Co surface shows that BaO-doped Co aligns more closely with experimental observations than Ba-doped Co. This implies that Ba on the Co surface is likely to be in an oxide form under reaction conditions. Understanding the kinetics of the ammonia decomposition reaction provides a foundation for developing highly effective catalysts to accelerate the industrial utilization of ammonia as a sustainable hydrogen carrier.

How Humans Run Faster: The Neuromechanical Contributions of Functional Muscle Groups to Running at Different Speeds.

How the neuromechanics of the lower limb functional muscle groups change with running speed remains to be fully elucidated, with implications for our understanding of human locomotion, conditioning, and injury prevention. This study compared the neuromechanics (ground reaction and joint kinetics, kinematics and muscle activity) of middle-distance athletes running on an instrumented treadmill at six wide-ranging speeds (2.78-8.33 m·s-1). Ground reaction forces and kinematics were analyzed using inverse dynamics to calculate flexor and extensor joint torques, and positive and negative work done by these torques. Contributions of each functional muscle group to the total positive and negative work done by the limb during stance, swing, and the whole stride were quantified. During stance, the ankle plantar flexors were the major energy generator and absorber (>60%) at all speeds, but their contribution to whole stride energy generation and absorption declined with speed. Positive work by the hip extensors rose superlinearly with speed during stance (3-fold) and especially during swing (12-fold), becoming the biggest energy generator across the whole stride at >5 m·s-1. Knee flexor and extensor negative work also rose superlinearly with speed during swing, with the knee flexors becoming the greatest energy absorber over the whole stride at >7.22 m·s-1. Across speeds, plantar flexor peak moment and positive work accounted for 97% and 96% of the variance in step length, and swing hip extension peak moment and positive work accounted for 98% and 99% of the variance in step frequency. There were pronounced speed, phase (stance/swing), and work (positive/negative) dependent contributions of the different functional muscle groups during running, with extensive implications for conditioning and injury prevention.

Mitigating the capacity fading of silicon nanoparticles through double carbon coatings and cobalt doping

Silicon (Si) is considered a highly promising anode material for lithium-ion batteries (LIBs), attributing to its suitable working potential and high specific capacity. Nevertheless, the enormous volume expansion during the lithiation, poor electron conductivity, and low lithium-ion (Li+) diffusion rate limit the application of Si anodes. Here, we design a novel single carbon layer and carbon nanotubes (CNT) coated Si nanoparticle (Si NP@C@CNT composites), in which the single carbon layer derived from citric acid separates between Si nanoparticle (Si NP), effectively avoiding the aggregation of Si NP, while the external carbon framework (CF) composed of CNT boosts the electrical contact between Si NP. Such micro-morphology structure can reduce the stresses during lithiation and promote the formation of stable solid electrolyte interface. Besides, the metallic cobalt (Co) and CNT can effectively enhance electrode conductivity and promote rapid electron transfer. The electrochemical testing results indicate that Si NP@C@CNT anode presents faster electrochemical reaction kinetics with excellent cycle stability (1055.1 mAh g−1 after 300 cycles at 0.5 A g−1) and rate performance (809.9 mAh g−1 at 5 A g-1). The special capacities and capacity retention of Si NP@C@CNT composites are 885.3 mAh g−1 and 85.9 % after 1000 cycles at 1 A g−1. In addition, the constructed full-cell NCM811// Si NP@C@CNT shows well reversible capacity. This research provides a novel idea for Si -based anode with excellent cycling stability, high electron transfer and fast Li+ diffusion ability for LIBs.

In-situ grown ternary metal hydroxides@3D oriented crumpled V2C MXene sheets for improved Electrocatalytic Oxygen Evolution Reaction

High valence multi transition metal hydroxides are greatly enriched with OER redox active sites due to strong synergy of heteroatomic nuclei. The efficiency of these redox active sites could be efficiently improved by coupling with highly conductive substrate. The advanced three-dimensional (3D) architecture and hydrophilic terminal functionalities of MXene (MX) considerably enhance the maximum utilization rate of anchored redox active sites by triggering the direct growth of these at MX substrate. Here-in, the freeze-dried 3D network of crumpled Vanadium-Carbide (V2C) MX sheets regulates the crystallization of in-situ grown NiFeCr multi transition metal hydroxides on MX scaffold through co-precipitation process. The XPS results suggest a synergistic chemical interaction of 3D MX scaffold with NiFeCr that modifies the electronic structure of the composite ensuring reduced charge transfer resistance. Besides, as found in FESEM morphological investigation, the well-dispersed NiFeCr multi-transition metal hydroxides are immobilized on open pores like structure of V2C-MX facilitate thoroughly accessible active sites. As a result, the NiFeCr@3D V2C-MX composite has shown an excellent electrocatalytic activity with an overpotential of 410 mV at a current density of 200 mA cm-2, Tafel slope of 100 mV dec in 1M KOH. Besides, the significant interaction between metallic centers and MXene support prevent detachment or agglomeration of active centers providing maximum interaction with the electrolytic ions, quick ionic OH- transportation, speedy and stable electron transfer channels thus ensure the long-term stability of NV-5MX during 53 h continuous operation of OER. Furthermore, we have utilized a more accurate value of half-cell standard reduction potential of the Hg/HgO electrode in the Nernst equation to represent all test voltages and to determine the overpotential values. In essence, this study features a facile approach for the confined growth of multi transition metal hydroxides in the presence of morphologically unique 3D crumpled V2C MXene architectures. Consequently, the increased OER reaction kinetics and improved stability of the synthesized composites are potentially due to synergistic interplay between well dispersed active sites and the conductive substrate.

Control interfacial charge transfer behavior by creating surface defects on structure unit of heterojunction to drive carrier separation for enhancing photocatalytic CO2 reduction

Controlling interfacial charge transfer behavior of heterojunction is an arduous issue to efficiently drive separation of photogenerated carriers for improving the photocatalytic activity. Herein, the interface charge transfer behavior is effectively controlled by fabricating an unparalleled VO-NiWO4/PCN heterojunction that is prepared by encapsulating NiWO4 nanoparticles rich in surface oxygen vacancies (VO-NiWO4) in the mesoporous polymeric carbon nitride (PCN) nanosheets. Experimental and theoretical investigations show that, differing with the traditional p-n junction, the direction of built-in electric field between p-type NiWO4 and n-type PCN is reversed interestingly. The strongly codirectional built-in electric field is also produced between the surface defect region and inside of VO-NiWO4 besides in the space charge region, the dual drive effect of which forcefully propels interface charge transfer through triggering Z-Scheme mechanism, thus significantly improving the separation efficiency of photogenerated carriers. Moreover, the unique mesoporous encapsulation structure of VO-NiWO4/PCN heterostructure can not only afford the confinement effect to improve the reaction kinetics and specificity in the CO2 reduction to CO, but also significantly reduce mass transfer resistance of molecular diffusion towards the reaction sites. Therefore, the VO-NiWO4/PCN heterostructure demonstrates the preeminent activity, stability and reusability for photocatalytic CO2 reduction to CO reaction. The average evolution rate of CO over the optimal 10%-VO-NiWO4/PCN composite reaches around 2.5 and 1.8 times higher than that of individual PCN and VO-NiWO4, respectively. This work contributes a fresh design approach of interface structure in the heterojunction to control charge transfer behaviors and thus improve the photocatalytic performance.

High-throughput arousing interconnected interfaces for excellent sodium storage chemistry

Heterostructures endow electrochemical hybrids with promising energy storage properties owing to synergistic effects and interfacial interaction. However, developing a facile but effective approach to maximize interface effects is crucial but challenging. Herein, a bimetallic sulfide/carbon heterostructure is realized in a confined carbon network via a high-throughput template-assisted strategy to induce highly active and stable electrode architecture. The designed heterostructures not only yield abundant interconnected Co9S8/MoS2/N-doped carbon (Co9S8/MoS2/NC) heterojunctions with continuous channels for ion/electron transfer but maintain excellent conversion reversibility. Serving as anode for sodium storage, the Co9S8/MoS2/NC framework displayed excellent sodium storage properties (reversible capacity of 480 mAh/g after 100 cycles at 0.2 A/g and 286.2 mAh/g after 500 cycles at 2 A/g). Given this, this study can guide future design protocols for interface engineering by forming dynamic channels of conversion reaction kinetics for potential applications in high-performance electrodes.

Experimental investigation and CFD study of direct reduction of iron ore in the conical fluidized bed

The reduction behavior of iron ore is the fundamental process in ferrous metallurgy. Considering the gas–solid interface-structure relationship, heterogeneous transfer-reaction behavior, and multiple reaction kinetics, this work provides an effective analytical tool to investigate the fluidized reduction of iron ore. The conical fluidized bed is numerically examined to be capable of preventing de-fluidization induced by the sticking behavior, due to the steady circulation of flow pattern and full fluidization of coarse agglomerates. Compared with the hydrogen concentration, the gas velocity shows a stronger influence on the agglomerate reduction rate for the more efficient gas–solid contact. For the simulated transitions of Fe2O3 → Fe3O4 → Fe(1-x)O → Fe are assumed to overlap each other, there exist discrepancies between computed and theoretical reduction degrees. The experimental and numerical findings can be used to develop a methodology for optimizing the operational complexity and economic benefits of the fluidized reduction of iron ore.

Study on Dynamic Liquid-Carrying Process of Foaming Agent and Establishment of Mathematical Model.

The efficiency of foam drainage gas recovery is predominantly dictated by the performance of the foaming agent. To better understand their behavior, a novel testing apparatus was developed to simulate the foam drainage gas recovery process within the wellbore. Through the dynamic liquid-carrying performance tests of four foaming agents under uniform conditions, it was discerned that there existed significant disparities in the liquid-carrying performance and action duration. Further interface performance analysis disclosed that the liquid-carrying capacity and the duration were correlated with their adsorption capacity and interface activity at the gas-liquid interface. Notably, foaming agents with lower adsorption capacity and higher interfacial activity demonstrated superior liquid-carrying performance and longer action duration. By analyzing the consumption of foaming agents during the liquid-carrying process, five dynamic liquid-carrying equations were derived based on first-order reaction kinetics, the Malthusian population model, and the logistic function. The outcomes demonstrated that all these five equations could precisely delineate the dynamic liquid-carrying process of the foaming agent. During the research, we found that the consumption of the foaming agent in the foam drainage gas recovery process is related to its adsorption behavior at the gas-liquid interface, and revealed that the dynamic liquid-carrying process of foaming agent is the increasing process of liquid-carrying capacity under the continuous consumption of limited foaming agent resources. This laid a foundation for the further exploration of the functional mechanism of the foaming agent in the foam drainage gas recovery process.

Empowering lithium-ion storage: unveiling the superior performance of niobium-based oxide/perovskite heterojunction with built-in electric field

The increasing demand for high-performance electrode materials in lithium-ion batteries has driven significant attention towards Nb2O5 due to its high working voltage, large theoretical capacity, environmental friendliness, and cost-effectiveness. However, inherent drawbacks such as poor electrical conductivity and sluggish electrochemical reaction kinetics have hindered its lithium storage performance. In this study, we introduced KCa2Nb3O10 into Nb2O5 to form a heterojunction, creating a built-in electric field to enhance the migration and diffusion of Li+, effectively promoting electrochemical reaction kinetics. Under the regulation of the built-in electric field, the charge transfer resistance of the KCa2Nb3O10/Nb2O5 anode decreased by 3.4 times compared to pure Nb2O5, and the Li+ diffusion coefficient improved by two orders of magnitude. Specifically, the KCa2Nb3O10/Nb2O5 anode exhibited a high capacity of 276 mAh g−1 under 1 C, retaining a capacity of 128 mAh g−1 even at 100 C. After 3000 cycles at 25 C, the capacity degradation was only 0.012 % per cycle. Through combined theoretical calculations and experimental validation, it was found that the built-in electric field induced by the heterojunction interface contributed to an asymmetric charge distribution, thereby improving the rates of charge and ion migration within the electrode, ultimately enhancing the electrochemical performance of the electrode material. This study provides an effective approach for the rational design of high-performance electrode materials.

High-Entropy-Inspired Multicomponent Electrical Double Layer Structure Design for Stable Zinc Metal Anodes.

Regulating the electrical double layer (EDL) structure can enhance the cycling stability of Zn metal anodes, however, the effectiveness of this strategy is significantly limited by individual additives. Inspired by the high-entropy (HE) concept, we developed a multicomponent (MC) EDL structure composed of La3+, Cl-, and BBI anions by adding dibenzenesulfonimide (BBI) and LaCl3 additives into ZnSO4 electrolytes (BBI/LaCl3/ZnSO4). Specifically, La3+ ions accumulate within EDL to shield the net charges on the Zn surface, allowing more BBI anions and Cl- ions to enter this region. Consequently, this unique MC EDL enables Zn anodes to simultaneously achieve uniform electric field, robust SEI layer, and balanced reaction kinetics. Moreover, the synergistic parameter-a novel descriptor for quantifying collaborative improvement-was first proposed to demonstrates the synergistic effect between BBI and LaCl3 additives. Benefitting from these advantages, Zn metal anodes achieved a high reversibility of 99.5% at a depth of discharge (DoD) of 51.3%, and Zn|MnO2 pouch cells exhibited a stable cycle life of 100 cycles at a low N/P ratio of 2.9.