Fast Reaction Kinetics Research Articles

Endowing V6O13/CeVO4 heterojunction with substantial improvements on zinc ion storage performance

The slow ion diffusion stemming from the high charge density of Zn2+ renders zinc-ion batteries (ZIBs) low reaction kinetics and cyclic stability. Herein, a series of nanoflake-shaped V6O13/CeVO4 composites containing oxygen vacancies with different feed ratios of cerium and vanadium are synthesized by one-step hydrothermal method. The design of V6O13-CeVO4 heterostructure can generate the built-in electric field, offering an additional driving force to accelerate electron transfer and thus enhance its overall electrical conductivity. Significantly, the enhanced adsorption energy of Zn2+ on the heterointerfaces is beneficial to stimulate the fast reaction kinetics. The induced abundant oxygen vacancies serve as the ample active sites to facilitate ion transport. Therefore, the construction of heterojunction and vacancy can be considered as a dual-drive strategy to promote the electrochemical performance. As a result, the ZIBs cathode based on the optimal V6O13/CeVO4-6 heterostructure exhibits an ultra-high capacity (280 mA h g−1 after 300 cycles at 1 A/g), rate capability, and long-cycle life (206.4 mA h g−1 after 4000 cycles at 10 A/g with a 78.2% capacity retention). Together with the deep investigation on the storage mechanism and kinetics analysis of Zn2+ through a series of ex situ characterizations and theoretical calculation, this study is valuable for the development of new vanadium-based cathodes for high-performance ZIBs.

PVP surface modification layer spacing and vacancy enhanced zinc ions storage and stability

Zinc ion batteries (ZIBs) have attracted extensive research in the field of electrochemical energy storage due to their lower cost, and higher safety. However, due to the large hydration radius of zinc ions have a large hydrated ionic radius, which makes it difficult to embed zinc ions in the cathode material and affects the electrochemical Therefore, the study of suitable cathode materials is one of the keys to the practical application of aqueous zinc ion batteries. In this paper, a functional cathode combining PVP as a surfactant and VS4 was designed with increased chain spacing and V3+ self-doping. This effectively induces abundant sulfur vacancies and selectively exposes a large amount of surface active surface (020), leading to improved Zn2+ intercalation kinetics, fast electrolyte penetration, and high process structural stability during insertion/extraction. Therefore, this new PVP-VS4 structure exhibits excellent electrochemical performance as the cathode of Zn-ion batteries, with a discharge specific capacity of 343 mAh g−1 at 0.1 A g−1; and a discharge specific capacity of 222 mAh g−1 after 2000 cycles at a current density of 2 A g−1, with a capacity retention rate close to 100 %. The fast reaction kinetics of the interaction reaction was further confirmed by corona intermittent titration (Gitt). Using a number of systematic studies and investigations of the pseudocapacitor contribution, we also concluded the energy storage mechanism and the ideal pseudocapacitor behavior. Moreover, PVP-VS4 is more resistant to self-discharge than the support VS4. In addition, we designed PVP-MnOx composites and PVP-induced co-engineering provides new and original opportunities to develop a range of efficient intercalation materials for the next energy storage technology.

Fe‐Ni2P@NPC Synthesized by Trametes Orientalis as an Efficient Electrocatalyst for the Oxygen Evolution Reaction

AbstractDeveloping non‐noble metal catalysts for the oxygen evolution reaction (OER) is one of the main challenges in the production of hydrogen energy by water splitting reaction. Herein, taking advantage of the fact that microorganisms have high element contents and metabolic activities, we used them to recycle Ni and Fe from electroplating sludge. Based on the above, we designed a highly efficient oxygen evolution catalyst (Fe‐Ni2P@NPC) through the in situ synthesis of Fe‐doped Ni2P nanoparticles and N, P dual‐doped carbon materials coupled together. The material exhibited excellent catalytic activity, with a low overpotential of 282 mV at the current density of 10 mA cm−2 along with a fast reaction kinetics, with a small Tafel slope of 57.1 mV dec−1. This outstanding OER performance is mainly attributed to the in situ doping of Fe in Ni2P nanoparticles, resulting in a strong synergistic effect between them. Besides, the strong coupling interaction between Fe‐Ni2P and Fe‐NiOOH formed during the OER can adjust the electron distribution and optimize the adsorption capacity of the intermediates. This work provides a reference for the recycling of valuable Ni and Fe metals from electroplating sludge, as well as new insight into the preparation of low‐cost and high‐performance OER catalysts.

A self-supported 3D porous high entropy alloy with progressive formation of needle-shaped nanowires during reactions for maintained excellent electrocatalytic oxygen evolution

An efficient 3D porous bulk electrocatalyst is a feasible way to improve the conductivity. Herein, the preparation of a novel self-supporting 3D porous bulk FeCoNiMgB catalyst exhibits excellent electrocatalytic activity and stability properties towards OER. The self-supporting 3D porous framework structure catalyst possesses multiple advantages including large surface area, excellent conductivity, leading to the fast mass and charge transfers, low electrochemical impedance and fast water splitting reaction kinetics. As a result, the 3D porous bulk FeCoNiMgB catalyst requires substantially lower overpotential (234 mV) with a small Tafel slope (36.1 mV dec−1) as compared to pure FeCoNiMgB powders and RuO2 electrodes, as well as stable catalytic properties for over 72 h with no obvious evidence of degradation. Comparative structural characterization and DFT calculations reveal that the needle-shaped nanowires with Fe rich are formed from many open pores during the OER process, which helps to reduce the rate determining step energy barrier (O∗→OOH∗) for OER, and thus has excellent long-term electrochemical stability for continuous oxygen production under alkaline conditions. This work provides a new feasible and promising protocol to realize a novel self-supporting 3D porous bulk high entropy alloy catalyst as an inexpensive catalyst for efficient water splitting.

Axial Chlorine Induced Electron Delocalization in Atomically Dispersed FeN4 Electrocatalyst for Oxygen Reduction Reaction with Improved Hydrogen Peroxide Tolerance.

Atomically dispersed iron sites on nitrogen-doped carbon (Fe-NC) are the most active Pt-group-metal-free catalysts for oxygen reduction reaction (ORR). However, due to oxidative corrosion and the Fenton reaction, Fe-NC catalysts are insufficiently active and stable. Herein, w e demonstrated that the axial Cl-modified Fe-NC (Cl-Fe-NC) electrocatalyst is active and stable for the ORR in acidic conditions with high H2 O2 tolerance. The Cl-Fe-NC exhibits excellent ORR activity, with a high half-wave potential (E1/2 ) of 0.82V versus a reversible hydrogen electrode (RHE), comparable to Pt/C (E1/2 = 0.85V versus RHE) and better than Fe-NC (E1/2 = 0.79V versus RHE). X-ray absorption spectroscopy analysis confirms that chlorine is axially integrated into the FeN4. More interestingly, compared to Fe-NC, the Fenton reaction is markedly suppressed in Cl-Fe-NC. In situ electrochemical impedance spectroscopy reveals that Cl-Fe-NC provides efficient electron transfer and faster reaction kinetics than Fe-NC. Density functional theory calculations reveal that incorporating Cl into FeN4 can drive the electron density delocalization of the FeN4 site, leading to a moderate adsorption free energy of OH* (∆GOH* ), d-band center, and a high onset potential, and promotes the direct four-electron-transfer ORR with weak H2 O2 binding ability compared to Cl-free FeN4, indicating superior intrinsic ORR activity.

A scalable slurry process to fabricate CuZr amorphous alloy with hybrid lithiophilic oxides for lithium metal anode

The lithium metal is the most promising candidate anode for the next-generation lithium batteries, its wide-scale application will be accelerated if its electrode preparation process is feasible and compatible with the current electrode preparation approach used in the battery industry. Here the powder form of CuZr metallic glass was applied for lithium metal anode application, which was one-step chemically dealloying treated in the hydrofluoric acid solution prior to usage. The as-prepared CuZr powder (CuZr-D*) displays enlarged specific surface area with hybrid lithiophilic CuxO/ZrO2 oxides decorated on the surface, which is capable to induce homogenous nucleation, promote fast reaction kinetics, and improve the reversible lithium plating/stripping process. Moreover, the CuZr in powder form makes it easily accessible with the slurry-based electrode preparation process currently applied in battery industry. As a result, the CuZr-D* based electrode demonstrates good symmetric cell performance of 1500 h at 1.0 mA cm−2/1.0 mAh cm−2, high coulombic efficiency of 97.5% after 200 cycles at 0.5 mA cm−2/1.0 mAh cm−2, cyclic stability and rate capability of full cells. This work supports the potential feasibility of amorphous alloy powder for lithium metal battery application.

Synthesis of CsPbBr3 in Micro Total Reaction System: Fast Operation Space Mapping and Subsecond Growth Process Monitoring.

Lead halide perovskite nanocrystals (LHP NCs) have the characteristics of fast reaction kinetics and crystal instability due to the intrinsically highly ionic bonding between the respective ions, which bring challenges for revealing the growth kinetics and practical applications. Compared with conventional batch synthesis methods, the single-function microreactor can achieve precise and stable control of the NCs synthesis process, but it still has the shortcoming of not being able to obtain information about the growth process. In this study, a micro Total Reaction System (μTRS) with remote control, online detection, and rapid data analysis functions is designed. μTRS can sample the photoluminescence information of CsPbBr3 NCs growth in ligand-assisted reprecipitation method. CsPbBr3 NCs with an emission range of 435-492 nm are successfully detected, which breaks the record of the smallest size of CsPbBr3 NCs synthesized directly from precursors. The real-time feature of μTRS enables the construction of an automated close-loop synthesis system. Besides, the rapid acquisition and timely processing of product information enable the rapid mapping of the operation space for CsPbBr3 NCs preparation, which provides a reliable and learnable data set for designing a fully autonomous microreaction system capable of synthesizingNCs.

Bidirectional Catalyst with Robust Lithiophilicity and Sulfiphilicity for Advanced Lithium–Sulfur Battery

AbstractThe application of lithium–sulfur batteries (LSBs) is immensely impeded by notorious shuttle effect, sluggish redox kinetics, and irregular Li2S deposition, which result in large polarization and rapid capacity decay. To obtain the LSBs with high energy density and fast reaction kinetics, herein, a heterostructure composed by nitrogen‐deficient graphitic carbon nitride (ND‐g‐C3N4) and MgNCN is fabricated via a magnesiothermic denitriding technology. Lithophilic C3N4 with abundant nitrogen‐deficient acts as a conductive framework, together with the sulfiphilic MgNCN, lithium‐polysulfides (LiPSs) can be effectively captured followed by a regulated Li2S nucleation. Furthermore, the oxidation conversion kinetics can be accelerated as well. As expected, the LSBs with catalytic MgNCN/ND‐g‐C3N4 as the interlayer exhibit remarkable electrochemical performance with a discharge capacity of 650 mAh g−1 at 4 C. Meanwhile, a low capacity decay of 0.008% per cycle can be reached at 1 C after 400 cycles. Even with a high areal sulfur loading of 5.1 mg cm−2, outstanding capacity retention can be achieved at 0.5 C (64.18%) and 1 C (90.46%). The presented strategy unlocks a new way for the LSBs design with highly efficient catalyst.

Site-specific bioorthogonal protein labelling by tetrazine ligation using endogenous β-amino acid dienophiles.

The tetrazine ligation is an inverse electron-demand Diels-Alder reaction widely used for bioorthogonal modifications due to its versatility, site specificity and fast reaction kinetics. A major limitation has been the incorporation of dienophiles in biomolecules and organisms, which relies on externally added reagents. Available methods require the incorporation of tetrazine-reactive groups by enzyme-mediated ligations or unnatural amino acid incorporation. Here we report a tetrazine ligation strategy, termed TyrEx (tyramine excision) cycloaddition, permitting autonomous dienophile generation in bacteria. It utilizes a unique aminopyruvate unit introduced by post-translational protein splicing at a short tag. Tetrazine conjugation occurs rapidly with a rate constant of 0.625 (15) M-1 s-1 and was applied to produce a radiolabel chelator-modified Her2-binding Affibody and intracellular, fluorescently labelled cell division protein FtsZ. We anticipate the labelling strategy to be useful for intracellular studies of proteins, as a stable conjugation method for protein therapeutics, as well as other applications.

Engineering sulfuric acid-pretreated biochar supporting MnO2 for efficient toxic organic pollutants removal from aqueous solution in a wide pH range

Manganese dioxides (MnO2) and biochar materials are both desirable candidates for environmental remediation of toxic organic pollutants (TOPs) in water due to wide availability and environmental-friendly. In practical application, however, MnO2 suffers from low redox activity owing to deprotonation, while biochar is subject to limited removal capacity. Herein, a difunctional engineering sulfuric acid-pretreated biochar supporting MnO2 composite (MBC-A) was firstly synthesized and optimized to remove various TOPs from aqueous solution. Specifically, sulfuric acid not only served as an active agent to improve the specific surface area of biochar for improvement of adsorption capacity and more MnO2 loading, but also facilitated the introduction of sulfonic acid groups (-SO3H) as an internal proton reservoir to inhibit inactivation of MnO2 due to deprotonation in alkaline. Thanks to adsorption and oxidation, MBC-A showed excellent removal capacity (214.9 mg/g) and fast reaction kinetics (360 min) for tetracycline (TC), exceeding precursor and other materials reported in literature. Importantly, the effective operation pH range of MBC-A was broadened to 1–13 with the help of buffering capacity of –SO3H groups. The dominant driving force of adsorption were π-π interaction and hydrogen bond; while reactive oxidative species were mainly ascribed to singlet oxygen (1O2), hydroxyl radical (·OH) and reactive Mn3+. The possible reactive sites and pathway were investigated by combining experimental results with density functional theory (DFT) calculation. Further, the results of multiple cyclic runs, removal in real river water and toxicity assessment demonstrated well reusability, high environmental security, and excellent practical applicability of MBC-A.

Defect-activated ternary carbon composite: A multifunctional electrocatalyst for efficient oxidation of water, urea, glucose, ORR, and zinc-air batteries

Designing a low-cost multifunction electrocatalyst that can synergistically catalyze multiple reactions in alkaline media while operative for long periods is of paramount importance for the hydrogen economy. Particularly, defect-activated electrocatalysts can significantly improve electrolytic performance by altering their chemical properties and electronic structures. However, developing defect-rich electrocatalysts with multiple active sites for efficient electro-oxidation of water remains challenging. In this respect, we present a straightforward strategy to design a defect-activated multifunctional ternary carbon composite by integrating graphene oxide (GO), Mxene (Mx), and graphitic carbon nitride (CN). Benefiting from the well-integrated 2D interfacial coupling of different carbon nanostructures, carbon composite has several advantageous properties including superior electric conductivity, higher specific surface area, activated surface defects, and highly accessible multicomponent surface-active sites. In addition, carbon composite exhibited macroporous 3D architecture for free migration of oxygen species and electrons. Accordingly, the carbon composite served as a multifunctional electrocatalyst in alkaline media, displaying superior electrolytic activities toward oxygen evolution reaction (OER), urea oxidation reaction (UOR), glucose oxidation reaction (GOR), and oxygen reduction reaction (ORR). Moreover, the Zn-air batteries (ZABs) fabricated with Zn anode and carbon composite as air-cathode demonstrated to have a high-power density, high discharge voltage, and excellent cycling stability in alkaline media. The exceptional electrolytic performance is attributed to the defect-rich interfaces and the synergistic interactions between the multi-components of carbon composite, which not only facilitate free accessible volume for rapid diffusion of oxygen-related species but also maintain the structural integrity during the reaction, thus allowing its comparable fast reaction kinetics. Overall, this work presents a simple and scalable strategy to design an efficient, stable, and eco-friendly multifunctional electrocatalyst that has the potential to be used in a wide range of applications in energy conversion and storage.

In situ growth of metal hexacyanoferrate crystals on alginate beads for effective removal of radioactive cesium (137Cs) from seawater

Metal hexacyanoferrates (Me-HCFs) are highly effective materials for removing radioactive Cs (137Cs) in seawater. For their practical application, granulation of Me-HCFs is necessary. However, conventional granulation techniques using a polymer as a binding material adversely affect the adsorption performance of Me-HCFs by blocking their adsorption sites. In the present work, to minimize the interference of the binding material, Me-HCF crystals were synthesized on an alginate bead surface in situ for the treatment of 137Cs+-contaminated seawater. Three different Me-HCFs immobilized on alginate beads (Fe-HCF, Cu-HCF, and Co-HCF) were prepared via a simple and rapid method involving a reaction between ionophorically crosslinked alginate beads (Fe3+, Cu2+, and Co2+ ions) and HCF solution. Among them, Fe-HCF crystals were successfully grown on the alginate bead surface; the other crystals were hardly synthesized despite a longer reaction time. The Fe-HCF crystals composed 15.0 % (w/w) of the beads and were located on the surface of the beads rather than being embedded in the alginate matrix. Because the Fe-HCF crystals were located at the surface of the alginate beads, Cs+ adsorption onto the Fe-HCF crystals showed fast reaction kinetics (achieving equilibrium in ∼ 3 h) and a high Cs+ adsorption capacity (∼33.5 mg/g). Also, a feasibility test was carried out for the removal of radioactive 137Cs+ in real seawater medium. Finally, a continuous Cs+ removal test was conducted in a packed column of the Fe-HCF beads. It was able to treat 65 bed volume of 50 mg/L of Cs+ solution with a flow rate of 1 mL/min.

Expounded Photoelectric and Electrochemical Profiling of LRE3+:β‐Ta2O5 (Ln3+ = Ce3+, Pr3+, Nd3+) for High Performance in Energy Systems

Light rare earth (LRE3+) ions‐doped Ta2O5 semiconductor material is synthesized via coprecipitation method with the bandgap energy of 3.94–4.05 eV and an orthorhombic geometry with 74.49 nm size. The rare earth‐modified Ta2O5 improves the photovoltaic functionality of the fully ambient perovskite solar cell by efficient extraction of electrons and blocking of the holes. The device achieved an efficiency of 13.36% with 63% of fill factor and negligible hysteresis index. LRE3+ triply doped Ta2O5 is used for the fabrication of an electrode by decorating on the nickel foam. This electrode outperforms the conventionally used materials by achieving a specific capacitance of 517.5 F g−1 marked by fast reaction kinetics and diffusion with an equivalent series resistance of 0.18 Ω. LRE3+‐doped Ta2O5 is proved to be an excellent electrode material with the characteristic electric double‐layer capacitance behavior in conjugation with the Faradic pseudocapacitive behavior. Finally, the electrocatalysis using this material indicates its excellence as a H2 generating catalyst in comparison to O2 generation with the smallest overpotential and Tafel slope values of 143 mV and 125.3 mV dec−1, respectively. The designed electrode expressed an exceptional stability over ambient conditions as well as inside an electrolyte.

Sulfurized poly(o-phenylenediamine) as a novel high-performance solid-phase conversion sulfur cathode

The combination of sulfurized polymer cathode and ester-type electrolyte can realize the solid-phase conversion of sulfur cathode, which is a promising solution of the dissolution issue of Li–S batteries. In this regard, sulfurized polyacrylonitrile (SPAN) is the most famous material and few attempts have been made to challenge it in the past two decades. Herein, we report sulfurized poly(o-phenylenediamine) (SPoPDA) as its supplement or alternative for rechargeable lithium batteries. Compared with SPAN, SPoPDA shows higher ability to covalently bond with sulfur (from ∼50 to ∼60 wt%), similar reversible capacity (∼600 mAh g−1), better cycling stability (with only 2% loss of charge capacity during 100 cycles), and faster reaction kinetics. The molecular structures and electrochemical reaction mechanisms of them have been quantitatively analyzed, and the electrode structure variation of SPoPDA during discharge–charge process has been thoroughly investigated. This work provides not only a novel sulfurized polymer cathode material with low cost, easy synthesis, and high electrochemical performance, but also clearer mechanism understanding of solid-phase conversion sulfur cathode, which are of significant importance for the development of Li–S batteries towards practical application.

Effectual Water Oxidation Reinforced by Three-Dimensional (3D) MnO: A Highly Sustainable Electrocatalyst

Fabricating highly effective, durable, eco-friendly, and low-cost electrocatalysts are challenging in renewable energy applications. Manganese(II) oxide (MnO), an oxygen evolution reaction (OER) catalyst, is an appealing contender in electrocatalytic water oxidation. Herein, we report the fabrication of single-phase MnO films over nickel foam (NF) as 3D electrode materials via a facile aerosol-assisted chemical vapor deposition (AACVD). HR-TEM confirms the nanoscale composition and polycrystalline structure, while the cauliflower-like morphology was observed under FE-SEM supported by EDX for conforming elemental composition. XRD and XPS analysis proved their chemical structure and oxidation states. The electrochemical investigations of MnO films prepared at 60 min revealed excellent OER performance in 1.0 M KOH. The benchmark decade current density was achieved just at an overpotential of 150 mV, whereas at an overpotential of 430 mV, Mn@NF-60 showed a maximum current density of 1158 mA cm–2 which is 4–6-folds better than its counterparts. The large electrochemical surface area (154 cm2), lower Tafel slope (80.93 mV/dec), and charge transfer resistance (18 Ω), excellent durability throughout extended chronopotentiometry analysis, and fast electron transfer reaction kinetics for OER comprehend Mn@NF-60 as an effectual electrocatalyst. These attributes of a single-phase MnO@NF-60 are credited to ample electroactive sites that enhance electron transfer processes. This study offered highly active single-phase metal oxide thin films by AACVD as 3D electrode materials for plentiful electrocatalytic applications.

A High‐Performance Alloy‐Based Anode Enabled by Surface and Interface Engineering for Wide‐Temperature Sodium‐Ion Batteries

AbstractAlloy‐based anodes have shown great potential to be applied in sodium‐ion batteries (SIBs) due to their high theoretical capacities, suitable working potential, and abundant earth reserves. However, their practical applications are severely impeded by large volume expansion, unstable solid‐electrolyte interfaces (SEI), and sluggish reaction kinetics during cycling. Herein, a surface engineering of tin nanorods via N‐doped carbon layers (Sn@NC) and an interface engineering strategy to improve the electrochemical performance in SIBs are reported. In particular, the authors demonstrate that uniform surface modification can effectively facilitate electron and sodium transport kinetics, confine alloy pulverization, and simultaneously synergize interactions with the ether‐based electrolyte to form a robust organic‐inorganic SEI. Moreover, it is discovered that the diethylene glycol dimethyl ether electrolyte with strong stability and an optimized Na+ solvation structure can co‐embed the carbon layer to achieve fast reaction kinetics. Consequently, Sn@NC anodes deliver extra‐long cycling stability of more than 10 000 cycles. The full cell of Na3V2(PO4)3║Sn@NC exhibits high energy density (215 Wh kg−1), excellent high‐rate capability (reaches 80% capacity in 2 min), and long cycle life over a wide temperature range of −20 to 50 °C.

Mechanistic Insights into the Atomic Distance Effect on Adsorption and Degradation of Aromatic Compounds

Atomic-level dispersed metal–N–C frameworks are considered effective materials for the catalytic oxidation of aromatic pollutants by modulating the electronic structures of atomic metal centers. However, the inherent electronic mechanism for the influence of varying anchoring atomic distances on the enrichment and further degradation of aromatic compounds is unclear. Herein, covalent triazine frameworks (CTFs) anchored by Ni single atoms (Ni-SA/CTF), Ni clusters (Ni-AC/CTF), and NiO nanoparticles (NiO-NP/CTF) were successfully constructed as reaction platforms. The results showed that Ni-AC/CTF exhibited the highest adsorption capacity (624.4 μmol g–1) for 2,2′,4,4′-tetrahydroxybenzophenone (BP-2) and the fastest reaction kinetics (3.01 h–1) for rhodamine B (RhB). The experiments and theoretical calculations further revealed that the interaction between Ni atoms in the atomic clusters in Ni-AC/CTF shortens the Ni–N bonds and weakens the asymmetric spin state. These changes cause benzene ring distortion in pollutant molecules, further promoting the ring cleavage reaction and improving electron delocalization and transport, which synergistically enhance the aromatic pollutant removal performance. This study explains the advantages of atomic cluster catalysts in the activation and degradation of aromatic pollutants at the electronic level, providing a direction for the development of advanced photocatalytic materials.

Bismuth doped Sr2Fe1.5Mo0.5O6-δ double perovskite as a robust fuel electrode in ceramic oxide cells for direct CO2 electrolysis

Electrochemical conversion of CO2 to CO is an economically feasible method for mitigating greenhouse gas emissions. Among various electrochemical approaches, solid oxide electrolysis cells (SOECs) show high potential for CO2 reduction reaction (CO2-RR) due to their ability to operate at high temperatures, resulting in fast reaction kinetics and increased efficiency. Considering their main energy loss is still associated with the large overpotential at the fuel electrode, the development of the highly efficient and durable cathode for SOECs has been extensively searched after. Here, we propose an A-site doping strategy to enhance the properties of Sr2Fe1.5Mo0.5O6−δ (SFM), which improve its performance as a cathode in SOECs for CO2-RR, demonstrating favorable activity and durability. The structural and physiochemical characterizations, together with DFT calculations, show that the partial replacement of Sr by Bi in the SFM double perovskite not only improves CO2 adsorption capability at the catalyst surface but also enhances oxygen ionic conduction inside the bulk oxide, resulting in enhanced CO2 electrocatalysis performance in SOECs. Specifically, a La0.8Sr0.2Ga0.8Mg0.2O3−δ (LSGM) electrolyte-supported single cell with the new Bi-doped SFM cathode demonstrates a large current density of 1620 mA cm−2 at a cell potential of 1.6 V at 850 °C with good operational stability up to 200 h. Bi-doped SFM thus represents a highly promising cathode for ceramic CO2 electrolyzers and could accelerate our transition towards a carbon-neutral society.

An Integrated Electrochemical System for Synergistic Cathodic Nitrate Reduction and Anodic Sulfite Oxidation.

Electrochemical reduction of nitrate has broad application prospects. However, in traditional electrochemical reduction of nitrate, the low value of oxygen produced by the anodic oxygen evolution reaction and the high overpotential limit its application. Seeking a more valuable and faster anodic reaction to form a cathode-anode integrated system with nitrate reaction can effectively accelerate the reaction rate of the cathode and anode, and improve the utilization of electrical energy. Sulfite, as a pollutant after wet desulfurization, has faster reaction kinetics in its oxidation reaction compared to the oxygen evolution reaction. Therefore, this study proposes an integrated cathodic nitrate reduction and anodic sulfite oxidation system. The effect of operating parameters (cathode potential, initial NO3--N concentration, and initial SO32--S concentration) on the integrated system was studied. Under the optimal operating parameters, the nitrate reduction rate in the integrated system reached 93.26% within 1 h, and the sulfite oxidation rate reached 94.64%. Compared with the nitrate reduction rate (91.26%) and sulfite oxidation rate (53.33%) in the separate system, the integrated system had a significant synergistic effect. This work provides a reference for solving nitrate and sulfite pollution, and promotes the application and development of electrochemical cathode-anode integrated technology.

High-Performance Poly(1-naphthylamine)/Mesoporous Carbon Cathode for Lithium-Ion Batteries with Ultralong Cycle Life of 45000 Cycles at -15°C.

Organic electrode materials for lithium-ion batteries have attracted significant attention in recent years. Polymer electrode materials, as compared to small-molecule electrode materials, have the advantage of poor solubility, which is beneficial for achieving high cycling stability. However, the severe entanglement of polymer chains often leads to difficulties in preparing nanostructured polymer electrodes, which is vital for achieving fast reaction kinetics and high utilization of active sites. This study demonstrates that these problems can be solved by the in situ electropolymerization of electrochemically active monomers in nanopores of ordered mesoporous carbon (CMK-3), combining the advantages of the nano-dispersion and nano-confinement effects of CMK-3 and the insolubility of the polymer materials. The as-prepared nanostructured poly(1-naphthylamine)/CMK-3 cathode exhibits a high active site utilization of 93.7%, ultrafast rate capability of 60Ag-1 (≈320C), and an ultralong cycle life of 10000 cycles at room temperature and 45000 cycles at -15°C. The study herein provides a facile and effective method that can simultaneously solve both the dissolution problem of small-molecule electrode materials and the inhomogeneous dispersion issue of polymer electrode materials.