Reduction In Activation Energy Research Articles

Zr-MOF/MXene composite for enhanced photothermal catalytic CO2 reduction in atmospheric and industrial flue gas streams

In this study, a novel composite was engineered by integrating Zr-MOF (NH2-UIO-66) with MXene layers through electrostatic self-assembly. Under simulated sunlight and at 80 °C, this composite material achieved nearly complete conversion of low-concentration atmospheric CO2 to CO and CH4 without additional sacrificial agents or alkaline absorption liquids, marking one of the few reports demonstrating near-complete reduction of low-concentration CO2 directly from the air. For high-concentration CO2 in industrial flue gas, the composite utilized residual heat at 80 °C without additional energy input, exhibiting excellent CO2 reduction efficiency with CO and CH4 production rates of 127 μmol·g-1·h-1 and 330 μmol·g-1·h-1, respectively, resulting in a total production rate 4.76 times higher than that in the air. Compared to most reports on thermocatalytic CO2 reduction (>300 °C), this material shows significant advantages below 100 °C. The performance improvement is attributed to the introduction of Zr-MOF, which provides additional active sites and reduces activation energy. Additionally, the localized surface plasmon resonance (LSPR) effect of MXene facilitates the migration of thermal charge carriers to Zr4+ sites within the MOF. Density Functional Theory (DFT) calculations validate these findings. Overall, Zr-MOF/MXene composite holds potential for reducing CO2 in air and industrial settings, advancing energy conversion and environmental management.

A comprehensive investigation of the impact of carbon-supported metal complexes of triaminoguanidine on the characteristics of a double-base propellant

ABSTRACT In this study, triaminoguanidine complexes grafted onto activated carbon (AC-TAG-Fe and AC-TAG-Co) were designed and investigated for their catalytic effect on the thermolysis of a double base propellant consisting of nitrocellulose (NC) and diethylene glycol dinitrate (DEGDN). The successful synthesis of transition metal complexes with triaminoguanidine and their subsequent grafting onto activated carbon were confirmed using various analytical techniques, including Fourier Transform Infrared Spectroscopy, Raman Spectroscopy, X-ray Diffraction, and Scanning Electron Microscopy. Thermal characterization using Thermogravimetric Analysis and Differential Scanning Calorimetry provided valuable insights into the thermal properties and reactivity of the elaborated NC/DEGDN-based composites. Importantly, the addition of various additives resulted in notable improvements in both the enthalpy of reaction and density. Isoconversional kinetic studies revealed that the incorporation of TAG-Fe and TAG-Co complexes reduced the apparent activation energy of the NC/DEGDN composite from 137.4 kJ/mol to 135.4 kJ/mol and 114.8 kJ/mol, respectively, suggesting their catalytic effect. Furthermore, it is found that the addition of activated carbon (AC) resulted in an increase in activation energy to 154 kJ/mol, whereas grafting TAG-Fe and TAG-Co complexes onto AC as a catalytic support subsequently reduced activation energy to 119 kJ/mol and 112 kJ/mol, respectively. Overall, this research serves as a valuable reference for future studies focusing on investigating the catalytic combustion characteristics of double-base solid propellants.

The Influence of Carbon Fiber on Crystallization and Morphology of Poly(Ether Ketone Ketone) Composites Towards High Rate Thermoplastic Manufacturing Processes

Recent interest in thermoplastic composites for aerospace applications is driven by the need for high-volume manufacturing of materials that display excellent mechanical, thermal, and solvent resistive properties. Specifically, a large component of the composite properties of thermoplastic composites are highly dependent on the crystalline fraction of the semi-crystalline polymer matrix of the reinforced system. This work investigates the melting behavior of poly (ether ketone ketone) (PEKK) and the influence of temperature and fiber on crystallization kinetics and morphology of (PEKK) composites utilizing, differential scanning calorimetry, Velaris-Sefaris modelling, and polarized optical microscopy (POM). Annealing temperatures of 380°C and above were required to fully erase crystalline ordering in the PEKK matrix. Furthermore, carbon fibers accelerated crystallization kinetics in PEKK at a range of temperatures observed via DSC, and Velaris-Sefaris modelling implied a shift from bulk to surface induced nucleation by the addition carbon fiber to the PEKK matrix, reducing activation energy of crystallization events. This nucleation behavior was visually confirmed through POM with observation of transcrystalline domains nucleated from the surface of a single carbon fiber.

The Influence of Carbon Fiber on Crystallization and Morphology of Poly(Ether Ketone Ketone) Composites Towards High Rate Thermoplastic Manufacturing Processes

Recent interest in thermoplastic composites for aerospace applications is driven by the need for high-volume manufacturing of materials that display excellent mechanical, thermal, and solvent resistive properties. Specifically, a large component of the composite properties of thermoplastic composites are highly dependent on the crystalline fraction of the semi-crystalline polymer matrix of the reinforced system. This work investigates the melting behavior of poly (ether ketone ketone) (PEKK) and the influence of temperature and fiber on crystallization kinetics and morphology of (PEKK) composites utilizing, differential scanning calorimetry, Velaris-Sefaris modelling, and polarized optical microscopy (POM). Annealing temperatures of 380°C and above were required to fully erase crystalline ordering in the PEKK matrix. Furthermore, carbon fibers accelerated crystallization kinetics in PEKK at a range of temperatures observed via DSC, and Velaris-Sefaris modelling implied a shift from bulk to surface induced nucleation by the addition carbon fiber to the PEKK matrix, reducing activation energy of crystallization events. This nucleation behavior was visually confirmed through POM with observation of transcrystalline domains nucleated from the surface of a single carbon fiber.

Improved ionic conductivity of La and Mg co-doped ceria nanocrystals synthesized by auto-combustion method

Ionic conductivity of La3+ and Mg2+ co-doped ceria, synthesized by auto-combustion method, is investigated here as electrolytes for intermediate-temperature solid oxide fuel cells (IT-SOFCs, operating below 800 °C). The prepared nanocrystalline electrolytes, LMDC10 (Ce0.9La0.05Mg0.05O2-δ) and LMDC20 (Ce0.8La0.1Mg0.1O2-δ) have exhibited improved ionic conductivities of 1.31 × 10−2 and 1.39 × 10−1 S cm−1 at 1073 K with reduced activation energies of 0.93 and 0.97 eV, respectively, when compared to conventional electrolytes like yttria-stabilized zirconia. The prepared samples are characterized by XRD, Raman spectra, XPS and FESEM which confirmed the formation of single-phasic cubic fluorite structure. Thus, the potential for La3+ and Mg2+ co-doped ceria electrolytes to offer cost-effective alternatives with low sintering temperatures and high performance for IT-SOFCs.

Synergistic effects of liquid phase sintering and B-site substitution to enhance proton conductivity of BaZr0.1Ce0.7Y0.1Yb0.1O3-δ for protonic ceramic fuel cell

This paper is dedicated to improving the sintering and conductivity of BaZr0.1Ce0.7Y0.1Yb0.1O3-δ (BZCYYb) by adding ZnO–CuO dual-sintering aids. The synergistic effects of liquid-sintering of Zn and B-site substitution of Cu on the sinterability and proton conductivity of BZCYYb are systematically investigated. X-ray diffraction (XRD) analysis of BZCYYb after addition of ZnO–CuO (BZCYYb-Zn-Cu) confirms the complete perovskite phase formation without any secondary phase. The substitution of Ce4+ (0.87 Å) with Zn2+ (0.74 Å) or Cu2+ (0.73 Å) induces a shift in XRD diffraction peak to higher angle due to a decrease in lattice constant. Energy dispersive X-ray spectroscopy analysis indicate a distinct distribution of Zn primarily at the grain boundaries, while Cu is predominantly located within the grains of BZCYYb-Zn-Cu. The addition of ZnO–CuO into BZCYYb results in a denser microstructure with larger average grain size. Furthermore, the substitution of Ce4+ by Cu2+ increases the concentration of oxygen vacancies and reduces activation energy. For BZCYYb-Zn-Cu, the proton conductivity reaches 4.52 × 10−2 S/cm at 750 °C, approximately 3 times higher than that of BZCYYb. This enhancement can be attributed to the synergistic effects of larger average grain size resulting from liquid phase sintering of Zn, low active energy, and high concentration of oxygen vacancies arising from Cu B-site substitution. BZCYYb-Zn-Cu is used as the electrolyte for anode support SOFC, and the single cell exhibits remarkable electrochemical performance and excellent stability in H2 fuel. This research establishes a crucial theoretical foundation for the preparation and performance evaluation for large-size protonic ceramic cell.

In-situ polymerized boehmite/ cashew gum/ polyvinyl alcohol/ polypyrrole blend nanocomposites with tunable structural, electrical, and mechanical properties for enhanced energy storage applications

This study describes the successful synthesis of boehmite (BHM) nanofiller-reinforced ternary blend nanocomposite films composed of polyvinyl alcohol (PVA), cashew gum (CG), and polypyrrole (PPy) using in-situ polymerization with water as the environmentally friendly solvent. The blend nanocomposites were characterized using Fourier-transform infrared spectroscopy (FTIR), field emission scanning electron microscopy (FE-SEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). FTIR analysis revealed chemical bonding between BHM and the biopolymer matrix at1071 cm-1. FE-SEM images exhibited a uniform distribution of BHM nanofillers within the CG/PVA/PPy matrix, particularly at a 10 wt% concentration. The addition of BHM significantly enhanced the thermal stability and the glass transition temperature of the nanocomposites. The temperature-sensitive AC conductivity, activation energy, and dielectric properties were examined using an impedance analyzer. AC conductivity analysis revealed reduced activation energy (1.277 × 10⁻5 eV at 7 wt% BHM) and increased dielectric constant (from 565.28 to 4411.22). The ternary blend nanocomposite demonstrated a significant 60.2 % increase in tensile strength, reflecting enhanced force resistance, while hardness values ranged from 26 to 30, classifying the films as soft and flexible. Overall, the study highlights significant enhancements in the morphological, electrical, thermal, dielectric, and mechanical properties of the nanocomposite films, emphasizing their promising potential for energy storage applications.

The universal gaseous detonation dynamics

The present communication proposes a new scaling approach to unify the dynamics of gaseous detonations subject to wall losses in both the narrow channels and small tubes, by compiling the published experimental data of detonations in 23 different mixtures with a very large range of cellular instabilities. A kinetic induction length Δi,loss can be determined from the detonation velocity deficit and detailed chemistry. In order to take into account the sensitivity of the latter length to post-shock temperature fluctuations (through the reduced activation energy θ), which is a partial and indirect marker of the cellular structure, and to bring out energetics (through the Chapman–Jouguet detonation Mach number MCJ), an effective kinetic length of Δi,loss(MCJ4/θ3) was built and has been shown to collapse the different detonation dynamics of various gaseous mixtures, subjected to wall losses, into a single universal curve for detonation velocity deficits.Novelty and Significance: Scaling analysis of large sets of published data of gaseous detonation experiments in narrow channels and small tubes has been made for 23 different mixtures with varied cellular instabilities and activation energies. The universal dynamics of gaseous detonations subject to wall losses in different mixtures has been achieved, for the first time, by adopting an effective kinetic length by taking into account the effect of both the activation energy and the energetics.

Phonon-Lithium Ion Interactions: A Case Study of LiM(SeO3)2 (M = Al, Ga, In, Sc, Y, and La).

Li ion diffusion is fundamentally a thermally activated ion hopping process. Recently, soft lattice, anharmonic phonon, and paddlewheel mechanism have been proposed to potentially benefit the ion transport, while the understanding of vibrational couplings of mobile ions and anions is still very limited but essential. Herein, we accessed the ionic conductivity, stability, and especially, lattice dynamics in LiM(SeO3)2 (M = Al, Ga, In, Sc, Y, and La) with two different types of oxygen anions within a LiO4 polyhedron, namely, edge-shared and corner-shared with MO6 polyhedra, the prototype of which, LiGa(SeO3)2, has been theoretically reported before with the similar structural features to NASICON and later experimentally synthesized with the room temperature conductivity ∼0.11 mS cm-1. It is interesting to note that LiM(SeO3)2 with a higher Li phonon band center shows higher Li conductivity, which is in contradiction to the conventional understanding of the importance for soft lattice to superionic conductors. The anharmonic and harmonic phonon interactions as well as the couplings between the vibration of the edge-bonded or corner-bonded anion in Li polyanions and the Li ion diffusion have been studied in detail. With transition metal M changing from La, Y, In, Ga, Al, and Sc, anharmonic phonons increase with reduced activation energy for Li diffusion. The phonon modes dominated by the edge-bonded oxygen anions contribute more to the migration of the Li ion than those dominated by the corner-bonded oxygen anions because of the greater atomic interaction between the Li ion and the edge-bonded anions. Thus, rather than the overall lattice softness, attention shall be given to reduce the frequency of the critical phonons contributing to Li ion diffusion as well as to increase the anharmonicity, i.e., through asymmetric Li polyhedra, for the design of Li ion superionic conductors for all-solid-state batteries.

Enhanced photocatalytic hydrogen evolution by S-scheme heterojunction and metal phosphide in NiTiO3/Graphdiyne

A key strategy to improve photocatalytic reaction efficiency is to achieve effective separation and migration of photo-generated carriers. Heterojunctions and co-catalysts are essential for boosting charge separation and transfer, reducing activation energy, and providing active sites for surface redox reactions. Herein, we introduce a composite catalytic system based on NiTiO3, enhanced with Graphdiyne (GDY) and NiP, achieving a hydrogen production activity of 8.37 mmol g−1 h−1. This performance is attributed to the combined effects of S-scheme heterojunction formation and NiP nanoparticle generation through phosphorylation. The S-scheme heterojunction effectively separates electron-hole pairs, reducing charge transport distance. Additionally, NiP nanoparticles formed in situ promote faster charge separation from NiTiO3 and act as active sites to accelerate the reduction half-reaction. Consequently, NiTiO3/GDY-P exhibits higher light absorption, faster charge separation, and superior redox capacity compared to NiTiO3. This work presents an efficient, eco-friendly multiphase catalytic system based on an S-scheme heterojunction and metal phosphide.

Structural defect and activated alumina of spheric α-Al2O3 improving alumina ceramics density from the industrial coarse gibbsite

The quality of alumina ceramics generally depends on alumina powder. High-density alumina ceramics were prepared from industrial coarse gibbsite. Near-spheric α-Al2O3 with particles smaller than 500 nm was produced via the synergy of B and F from NH4BF4. The near-spheric α-Al2O3 calcined at low temperature generated alumina ceramics with high density and low porosity. Meanwhile, the wet pretreatment yielded smaller particles with structural distortion and high microstrain and aluminum hydroxide, notably increasing the relative density of alumina ceramics. 99.18% relative density, 0.017% porosity, and 27.54 GPa Vickers hardness of alumina ceramics were achieved at 1650°C for 2 h without additives and pressed sintering. In addition, the early stage of sintering of alumina green body followed particle boundary diffusion with reduced activation energy in the sintering process. The close packing of the spheric α-Al2O3, high microstrain of α-Al2O3, structural defects with considerable AlO4 units calcined at low temperature, structural distortion in the alumina, and activated alumina on the α-Al2O3 surface collectively promoted the densification of alumina ceramics, achieving remarkable hardness, high density, and tiny porosity.

Debromination of Pyrolytic oil from waste printed circuit boards by catalytic thermo chemical reactions with Ca(OH)2 and ZSM-5

The surge in Waste Electrical and Electronic Equipment (WEEE) volume presents a formidable disposal challenge. This study focused on catalytic pyrolysis of waste printed circuit boards (WPCBs) employing Ca(OH)2 alone and in conjunction with ZSM-5 as catalysts. Kinetic parameters for catalytic and non-catalytic pyrolysis were derived through thermogravimetric analysis (TGA). The Coats-Redfern method for non-catalytic pyrolysis showcased activation energies of 33.52, 405.81, and 67.96 kJ/mol in zones 1, 2, and 3, respectively with corresponding reaction orders of 0.9, 2.8, and 1.2. Introduction of Ca(OH)2 amplified activation energy and reaction order in zones 2 and 3. Subsequent incorporation of ZSM-5 with Ca(OH)2 resulted in reduced activation energy and reaction order in zone 2, while elevating them in zones 1 and 3. Validation through laboratory-scale fixed-bed reactor experiments confirmed TGA findings and unveiled that pyrolysis oil had enhanced phenolic yield because of ZSM-5 where Ca(OH)2 showcased its effectiveness in eliminating halogens.

Simultaneously Boosting Direct and Indirect Urea Oxidation of Nickel Hydroxide via Strategic Yttrium Doping.

Urea electrolysis can address pressing environmental concerns caused by urea-containing wastewater while realizing energy-saving hydrogen production. Highly efficient and affordable electrocatalysts are indispensable for realizing the great potential of this emerging technology. Among the numerous candidates, α-Ni(OH)2 has the merits of good electrocatalytic activity, adjustable heteroelement doping, and low cost; consequently, it has received tremendous attention in the electrolytic fields. Herein, a Y3+-doping strategy is developed to effectively enhance the catalytic performance of nickel hydroxide in the urea oxidation reaction (UOR). Our results show that Y3+ incorporation successfully modulates the electronic structure of α-Ni(OH)2 by inducing Ni3+ formation in the crystal lattice to initiate direct UOR, facilitates the Ni3+/Ni2+ redox transition with higher current responses to promote indirect UOR, and maintains the structural stability of YNi-10 (Ni2+/Y3+ molar ratio = 1:0.1) during long-term UOR operation. Owing to these features, the obtained YNi-10 sample exhibits a higher current density (127 vs 79 mA cm-2 at 1.5 V), a lower Tafel slope (48 vs 75 mV dec-1), a larger potential difference between the UOR and oxygen evolution reaction (OER, 0.26 vs 0.22 V at 80 mA cm-2), a higher reaction rate constant (1.1 × 105 vs 3.1 × 103 cm3 mol-1 s-1), and a reduced activation energy of UOR (2.9 vs 14.8 kJ mol-1) compared with the Y-free counterpart (YNi-0). This study presents a promising strategy to simultaneously boost direct and indirect UORs, providing new insights for further developing high-performance electrocatalysts.

Unlocking Fast Ionic Transport in Sub‐Nano Channels of MOF‐Based Electrolytes for Next‐Generation Batteries

AbstractIncorporating appropriate molecules into ordered porous framework materials plays a pivotal role in modulating their physicochemical properties and dynamic behaviors. Such frameworked materials are also applicable for the preparation of solid‐state electrolyte (SSE) with altered electrochemical performance. In this work, MOF (Metal‐Organic Framework)‐based frameworked electrolytes (FEs) are prepared by the introduction of conductive ion‐molecule complexes and have investigated the electrochemical behaviors. The angstrom‐level pores in the framework enable efficient interactions with the complexes and participation in ion transportation by altering the coordinating environments of Li+ ions. As a result, the activated MOF‐based SSE exhibits an impressive ionic conductivity of 4.0×10−4 S cm−1 at room temperature (RT), along with a notably reduced activation energy of 0.12 eV at 350 K. The MOF‐based FE has been applied to Li /FE /LiFePO4 batteries, which exhibit excellent long‐cycling performance with virtually no capacity loss over 1000 cycles at the current density of 2 C at RT. The novel Li+ transport mechanisms where ion‐molecules would actively participate in the interactions between the framework and Li+ ions, not only present a new strategy for enhancing the ion transport kinetics, but also deliver outstanding electrochemical performance promising for next‐generation batteries.

The effects of 1D multi‐wall carbon nanotubes and 2D graphene nanoplatelets on curing behavior of epoxy/vinyl ester interpenetrating polymer network nanocomposites

AbstractThis study meticulously investigated the effect of two carbon allotrope nanofillers, two‐dimensional graphene nanoplatelets (GnPs) and one‐dimensional multi‐wall carbon nanotubes (MWCNTs) individually, at various loadings on the kinetics of curing of the epoxy (EP)/vinyl ester (VE) based interpenetrating polymer network (IPN) system, with a mass ratio of 1:1. The IPN system is including a liquid epoxy resin based on bisphenol A which has been cured by methyltetrahydrophthalic anhydride (MTHPA) in the presence of 1‐methyl imidazole (Mi) as an accelerator and a vinyl ester resin based on bisphenol A which has been cured by methyl ethyl ketone peroxide (MEKP). The curing behavior of all prepared nanocomposites under non‐isothermal conditions was studied using DSC at four heating rates. Two different isoconversional approaches were applied to evaluate the reaction kinetics, that is, the Friedman and the advanced Vyazovkin methods. The obtained activation energy curves for all samples revealed a complex curing behavior involving three stages: early IPN stage, IPN growth stage, and late IPN stage. Then, the activation energy values for each reaction step were determined based on the Friedman method. The presence of GnPs showed no catalytic effect on the reaction of VE with MEKP. In contrast, incorporating MWCNT nanoparticles considerably decreases the activation energy values of the reaction of ring opening of epoxides with MTHPA‐Mi and the reaction of esterification of the hydroxyl groups of VE with MTHPA.Highlights MWCNTs reduce activation energy in curing reactions for EP/MTHPA‐Mi and VE/MTHPA. GnPs do not catalyze VE/MEKP reaction unlike MWCNTs. Combining MWCNTs and GnPs enhances properties of IPN nanocomposites. Curing process includes early, growth, and late IPN stages impacting activation energy. SEM analysis reveals better dispersion of GnPs in IPN nanocomposites with MWCNTs.

Enriching Nano-Heterointerfaces in Proton Conducting TiO2-SrTiO3@TiO2 Yolk-Shell Electrolyte for Low-Temperature Solid Oxide Fuel Cells.

A challenging task in solid oxide fuel cells (SOFCs) is seeking for an alternative electrolyte, enabling high ionic conduction at relatively low operating temperatures, i.e., 300-600°C. Proton-conducting candidates, in particular, hold a significant promise due to their low transport activation energy to deliver protons. Here, a unique hierarchical TiO2-SrTiO3@TiO2 structure is developed inside an intercalated TiO2-SrTiO3 core as "yolk" decorating densely packed flake TiO2 as shell, creating plentiful nano-heterointerfaces with a continuous TiO2 and SrTiO3 "in-house" interfaces, as well the interfaces between TiO2-SrTiO3 yolk and TiO2 shell. It exhibits a reduced activation energy, down to 0.225eV, and an unexpectedly high proton conductivity at low temperature, e.g., 0.084 S cm-1 at 550°C, confirmed by experimentally H/D isotope method and proton-filtrating membrane measurement. Raman mapping technique identifies the presence of hydrogenated HO─Sr bonds, providing further evidence for proton conduction. And its interfacial conduction is comparatively analyzed with a directly-mixing TiO2-SrTiO3 composite electrolyte. Consequently, a single fuel cell based on the TiO2-SrTiO3@TiO2 heterogeneous electrolyte delivers a good peak power density of 799.7mW cm-2 at 550°C. These findings highlight a dexterous nano-heterointerface design strategy of highly proton-conductive electrolytes at reduced operating temperatures for SOFC technology.

CFD-aided enhancement of propylene oxide decomposition in a tubular reactor with a corrugated cooling jacket

_This research delves into the decomposition kinetics of propylene oxide within a novel reactor design characterized by a corrugated inner wall for enhanced cooling. By applying Computational Fluid Dynamics (CFD), this study aims to optimize the reactor's heat transfer capabilities to achieve precise control over the exothermic decomposition process. This approach addresses a previously unexplored area in CFD application, proposing a model that fine-tunes the decomposition efficiency of propylene oxide by considering the interplay of key parameters such as inlet mixture temperature, activation energy, flow rate, and the resulting thermal profile. The primary goal is to advance the development of more efficient and environmentally friendly chemical processing techniques in the propylene oxide industry. The study highlights the critical relationship between activation energy (74–76 kJ/mol), process temperature (29–37 °C), and cooling efficiency in optimizing the decomposition process. Significant findings indicate that higher inlet temperatures (37 °C) and lower activation energies (74 kJ/mol) lead to superior conversion rates. The study presents a clear correlation between temperature elevation, reduced activation energy, and enhanced conversion rates, demonstrating that optimizing these parameters can lead to significantly improved conversion efficiencies, potentially approaching 100 % under ideal conditions.

Scalable 2D Semiconductor‐Based van der Waals Heterostructure Interface with Built‐in Electric Field for Enhanced Electrochemical Water Splitting

Electrochemical water splitting has received tremendous attention as an eco‐friendly approach to produce hydrogen. Noble metals and their oxides are commonly used as electrocatalysts to reduce activation energy barriers for hydrogen and oxygen evolution reactions in high‐performance electrodes, but their cost, scarcity, and limited stability hinder widespread adoption of electrochemical water splitting. Further advancements are therefore needed to reduce reliance on noble metals and improve the long‐term stability. Herein, solution‐processed 2D van der Waals (vdW) p–n heterostructures as an interfacial layer between catalysts and the electrode are introduced to enhance the catalytic performance. These heterostructures are formed by sequentially assembling electrochemically exfoliated black phosphorus and molybdenum disulfide nanosheets into electronic‐grade p‐ and n‐type semiconductor thin films, with the scalability extending across tens‐of‐centimeter scale areas. Benefiting from the charge distribution and built‐in electric field developed upon heterojunction formation, the vdW heterostructure interfacial layer increases both the catalytic activity and stability of commercial Pt/C and Ir/C catalysts compared to when these catalysts are directly loaded onto electrodes. Additionally, the vdW heterostructure also serves as a template for synthesizing nanostructured Pt and Ir catalysts through electrodeposition, further enhancing the catalytic performance in terms of mass activity and stability.

Energy-efficient CO(2) conversion to multicarbon products at high rates on CuGa bimetallic catalyst

Electrocatalytic CO2 reduction to multi-carbon products is a promising approach for achieving carbon-neutral economies. However, the energy efficiency of these processes remains low, particularly at high current densities. Herein, we demonstrate that the low energy efficiencies are, in part, sometimes significantly, attributed to the high concentration overpotential resulting from the instability (i.e., flooding) of catalyst-layer during electrolysis. To tackle this challenge, we develop copper/gallium bimetallic catalysts with reduced activation energies for the formation of multi-carbon products. Consequently, the reduced activation overpotential allows us to achieve practical-relevant current densities for CO2 reduction at low cathodic potentials, ensuring good stability of the catalyst-layer and thereby minimizing the undesired concentration overpotential. The optimized bimetallic catalyst achieves over 50% cathodic energy efficiency for multi-carbon production at a high current density of over 1.0Acm−2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$1.0 \\, {{\\rm{A}}} \\, {{\\rm{cm}}}^{-2}$$\\end{document}. Furthermore, we achieve current densities exceeding 2.0Acm−2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$2.0 \\, {{\\rm{A}}} \\, {{\\rm{cm}}}^{-2}$$\\end{document} in a zero-gap membrane-electrode-assembly reactor, with a full-cell energy efficiency surpassing 30%.

Solid-State Lithium Batteries with in-Situ Polymerized Acrylate-Based Electrolytes Capable of Electrochemically Stable Operation at 100 ℃

In-situ polymerized acrylate-based polymers are very appealing as solid polymer electrolytes (SPEs) in lithium (Li) batteries due to the drop-in compatibility of such in-situ polymerization with conventional battery production, the ease of acrylate polymerization and their inexpensive, facile SPE chemistry. We identified, however, that such SPEs suffer from either a low cationic transference number with dual ion conducting salts (0.12-0.2) or a low ionic conductivity with single Li-ion conducting (SLIC) salts (6·10-6 S cm-1). In this project we overcame these limitations and developed significantly improved SPE with ionic conductivity of up to 2·10-4 Scm-1 and a relatively high Li-ion transference number of 0.4. With a significantly reduced fraction of mobile anions in the hybrid SPE, in-situ polymerized SPE cells with an LiFePO4 (LFP) cathode achieve a stable performance for over 100 cycles at temperatures as high as 100 °C, which is unattainable with conventional Li salts or electrolytes. Furthermore, the motional narrowing observed in the line-shapes of solid-state nuclear magnetic resonance (SS-NMR) spectra provided additional insights of the differences in Li nucleus environments and revealed a reduced activation energy for the hybrid salt SPEs due to their more open structure. This study opens the path for the fabrication of high-performance solid polymer lithium batteries capable of operating at high temperatures using commercial battery fabrication equipment. We expect that further tuning of the acrylate based SPE composition may allow further increases in its conductivity without sacrifices in its electrochemical stability or mechanical properties.