High Redox Research Articles

S-Scheme heterojunction of Cs2SnBr6/C3N4 with interfacial electron exchange toward efficient photocatalytic NO abatement

Photocatalytic technology is of great significance in environmental purification due to its eco-friendly and cost-effective operations. However, low charge-transfer efficiency restricts the photocatalytic activity of the catalyst. Herein, we report Cs2SnBr6/C3N4 composite catalysts that exhibit a robust interfacial electron exchange thereby enhancing photocatalytic nitric oxide (NO) oxidation. A comprehensive study has demonstrated the S-scheme electron transfer mechanism. Benefiting from the interfacial internal electric field, the C-Br bond serves as a direct electron transfer channel, resulting in enhanced charge separation. Furthermore, the S-scheme heterojunction effectively traps high redox potential electrons and holes, leading to the production of abundant reactive oxygen radicals that enhance photocatalytic NO abatement. The NO removal rate of the Cs2SnBr6/C3N4 heterogeneous system can reach 86.8 %, which is approximately 3-fold and 18-fold that of pristine C3N4 and Cs2SnBr6, respectively. The comprehensive understanding of the electron transfer between heterojunction atomic interfaces will provide a novel perspective on efficient environmental photocatalysis.

Formation of N‐Doped Carbon Nanofibers Decorated with MoP Nanoflakes for Dendrite‐Free Lithium Metal Anode

AbstractMetallic lithium (Li) is recognized as a promising candidate for anode material of Li‐ion batteries owing to high theoretical specific capacity and low redox potential. However, uncontrollable dendrite growth and huge volume expansion during Li plating/stripping processes hinder its practical application. Herein, N‐doped carbon nanofibers@MoP nanoflakes (NCNF@MoP) is developed as a potential host to address the above challenges. During the formation of solid electrolyte interphase, MoP nanoflakes can be changed into metallic Mo with high lithiophilicity and Li3P with high ionic conductivity. The whole composite host is transformed into a mixed ion/electron conducting network to reduce nucleation overpotential and accelerate diffusion kinetics at the electrode/electrolyte interface. As a proof of concept, the symmetric cell using NCNF@MoP host presents a long‐term cycling up to 2500 h with a low nucleation overpotential of 10 mV at 1 mA cm−2. Additionally, the Li‐NCNF@MoP||LiFePO4 full cell demonstrates a good capacity retention of 92.6% over 2200 cycles at a high current density of 5C (1 C = 169 mA g−1).

Operando insights into ammonium-mediated lithium metal stabilization: surface morphology modulation and enhanced SEI development

Lithium-ion batteries (LiBs) with graphite as an anode and lithiated transition metal oxide as a cathode are approaching their specific energy and power theoretical values. To overcome the limitations of LiBs, lithium metal anode with high specific capacity and low negative redox potential is necessary. However, practical application in rechargeable cells is hindered by uncontrolled lithium deposition manifesting, for instance, as Li dendrite growth which can cause formation of dead Li, short circuits and cell failure.The electrochemical behaviour of a protic additive (NH4PF6) in a carbonate-based electrolyte has been investigated by operando confocal Raman spectroscopy, in situ optical microscopy, and X-ray photoelectron spectroscopy, elucidating its functional mechanism. The ammonium cation promotes a chemical modification of the lithium metal anode-electrolyte interphase by producing an N-rich solid electrolyte interphase and chemically modifying the lithium surface morphology by electrochemical pitting. This novel method results in stable lithium deposition and stripping by a decreasing the local current density on the electrode, thus limiting dendritic deposition.

Boosted photocatalytic performance of hydrogen evolution and formaldehyde degradation with a S-scheme PMo12/MgIn2S4 heterojunction

Fabrication of a S-scheme heterojunction with staggered energy band structures can accelerate the charge separation and retain high redox potentials. Herein, a series of x wt% H3PMo12O40/MgIn2S4 (abbr. x% PMo12/MIS; x = 7.5, 10.0, 12.5, 15.0 and 17.5) S-scheme heterojunctions were successfully constructed by a hydrothermal technology and exhibited efficient and durable visible-light-driven photocatalytic properties of H2-evolution and formaldehyde (HCHO) degradation. Particularly, the 12.5 % PMo12/MIS sample represented the optimal H2 evolution rate of 232.53 μmol·g−1·h−1 with the apparent quantum efficiency (AQE) value of 1.52 % (λ = 420 nm), and HCHO removal rate of 64.20 % in 60 min. Moreover, the intermediate products formed during the removal process of HCHO were revealed through in situ DRIFTS method. The superior photocatalytic activities mainly stemmed from the enhanced absorption of visible light, and effective separation of photoinduced charge carriers. Furthermore, the S-scheme photocatalytic mechanism for PMo12/MIS system was confirmed via in situ irradiated X-ray photoelectron spectroscopy, radical capturing tests and electron spin resonance data, and semiconductor energy band theory. The current study affords a valuable perspective for fabricating highly efficient S-scheme heterojunction photocatalysts for hydrogen evolution and HCHO elimination.

Polymer hetero-electrolyte enabled solid-state 2.4-V Zn/Li hybrid batteries

The high redox potential of Zn0/2+ leads to low voltage of Zn batteries and therefore low energy density, plaguing deployment of Zn batteries in many energy-demanding applications. Though employing high-voltage cathode like spinel LiNi0.5Mn1.5O4 can increase the voltages of Zn batteries, Zn2+ ions will be immobilized in LiNi0.5Mn1.5O4 once intercalated, resulting in irreversibility. Here, we design a polymer hetero-electrolyte consisting of an anode layer with Zn2+ ions as charge carriers and a cathode layer that blocks the Zn2+ ion shuttle, which allows separated Zn and Li reversibility. As such, the Zn‖LNMO cell exhibits up to 2.4 V discharge voltage and 450 stable cycles with high reversible capacity, which are also attained in a scale-up pouch cell. The pouch cell shows a low self-discharge after resting for 28 days. The designed electrolyte paves the way to develop high-voltage Zn batteries based on reversible lithiated cathodes.

Hydrochloric acid induced microstructural reconfiguration from bulk α-NiS microspheres to porous/hollow NiSx microspheres for high-performance hybrid supercapacitor

Nickel sulfide is well known as a promising energy storage/conversion material considering its high redox activity, high theoretical capacity, easy preparation, and rich phase structures. Unfortunately, nickel sulfide prepared by conventional methods usually exhibits a bulk structure, which significantly limited its charge storage. To overcome this obstacle, we developed a facile hydrochloric acid-induced structure reconstruction strategy to fabricate porous and hollow structured nickel sulfide via a one-step hydrothermal process. We found that nickel sulfide undergoes de-nickelization in the presence of 3 M hydrochloric acid, resulting in the transformation from bulk structure to porous/hollow structures, accompanied by a transition from nickel-rich phase (α-NiS) to nickel-deficient phase (Ni3S4 or NiS2). The electrochemical results demonstrated the obviously improved specific capacity of nickel sulfide after structure reconstruction, among which the porous NS-HCl-1 h (α-NiS/Ni3S4) microspheres delivers the highest specific capacity (204.4 mAh g-1 at 1 A g-1) and show a rate performance about 50.0% from 1 to 20 A g-1. The assembled NS-HCl-1 h//rGO supercapacitor delivers a maximum energy density of 47.1 Wh kg-1 at a power density of 803.6 W kg-1, and maintain a capacity retention rate about 88.6% after 10,000 cycles. This work provides a novel method and contributes new insight for the structural reconstruction of transition metal sulfides (TMSs).

Low But Persistent Organic Carbon Content of Hyperarid River Deposits and Implications for Ancient Mars

AbstractMars has many well‐exposed fluvial ridges and fluvio‐deltaic basins; in two of these locations, the Curiosity and Perseverance rovers are currently searching for signs of habitability. The distribution of organic carbon that might persist in ancient fluvial deposits present on Mars is not well understood. In this study, we set out to assess the preservation potential of organic carbon in a hyperarid fluvial environment with observations and analyses of the Amargosa River in Death Valley, California (United States). The lower reaches of the Amargosa River in Badwater Basin are nearly devoid of plants and contain low gradient, meandering channels, making them a valuable terrestrial analog for early martian fluvial systems. We analyzed sediment taken from fluvial deposits exposed in cutbanks of two bends of a meandering channel. We found total organic carbon abundances that were on average 0.15% up to a meter below the surface. X‐ray diffraction and electron microscopy analyses revealed a suite of high redox potential mineral phases (including iron and manganese oxides) mixed with detrital and authigenic silicates, carbonate, and sulfate salts at or close to redox equilibrium with pore fluids in contact with the atmosphere. This finding highlighted that organic carbon can persist in fluvial deposits at low abundance despite oxidizing conditions and saturated sediments and suggested that ancient fluvial deposits on Mars may retain traces of organics in fine‐grained deposits if they are present during deposition.

Synergistic effect of MnS@Bi2S3 nanosheets for enhanced electrochemical performance in aqueous electrolyte supercapacitor application

With the low electronegativity of sulfur to oxygen, metal sulfides have become of much interest in energy storage system application, due to their high redox reactive sites and structure stability. However, composite of two or more metal sulfides is considered one of the strategies to improve the electrochemical properties, by utilizing the synergistic effect of the individual metal sulfides components. Here, MnS@Bi2S3 composites were obtained via three-step hydrothermal synthesized method. The MnS@Bi2S3 composite exhibited superior electrochemical performance with specific capacitance 185 F g−1, compared to MnS (22 F g−1) and Bi2S3 (45 F g−1) at current density 1 A g−1. Additionally, after 5000 cycles, MnS@Bi2S3 exhibited superior capacitance retention of 92 % compared to 40 % and 73 % for MnS and Bi2S3, respectively. The superior performance of MnS@Bi2S3 composite can be attributed to its higher specific surface area and the synergistic effect of MnS and Bi2S3.

Elaborate design and construction of direct Z-scheme ZnIn2S4@BiYWO6 heterojunction catalysts for efficient photocatalytic hydrogen production

Photocatalytic Hydrogen production as one of the effective ways to solve the future energy issues has recently become a research hotspot in the field of renewable energy. However, single-component photocatalysts have poor hydrogen production efficiency due to the narrow light-absorption range, susceptibility to photo-corrosion and low catalytic activity. Herein, novel heterojunction photocatalysts of ZnIn2S4@BiYWO6 with different mass ratios were designed and synthesized using a facile two-step hydrothermal method. Experimental results and analyses show that these heterojunction catalysts exhibit extremely excellent photocatalytic performance for hydrogen production. Especially, the hydrogen production rate of 10ZnIn2S4-BiYWO6 is 73 times higher than that of pure ZnIn2S4. Furthermore, enhanced photocatalytic mechanism and carrier transfer pathway in the heterojunction photocatalyst of ZnIn2S4@BiYWO6 were deeply analyzed and explored in the paper, which confirmed that ZnIn2S4@BiYWO6 is a direct Z-scheme heterojunction architecture. Within such a Z-scheme framework, the presence of a built-in electric field at the interface between ZnIn2S4 and BiYWO6 as well as the energy band bending lead to the direct recombination of electrons and holes with low redox capacity, while keeping the electrons and holes with high redox capacity in each component. Consequently, the photocatalytic activity of the Z-scheme heterojunction system has been greatly enhanced. It is believed that the present work provides valuable guidance for the design and construction of novel Z-scheme heterojunction photocatalysts.

Quantitative Optical Redox Imaging of Melanoma Xenografts with Different Metastatic Potentials.

To develop imaging biomarkers for tumors aggressiveness, our previous optical redox imaging (ORI) studies of the reduced nicotinamide adenine dinucleotide (NADH) and oxidized flavoproteins (Fp, containing flavin adenine dinucleotide, i.e., FAD) in tumor xenografts of human melanoma associated the high optical redox ratio (ORR = Fp/(Fp + NADH)) and its heterogeneity to the high invasive/metastatic potential, without having reported quantitative results for NADH and Fp. Here, we implemented a calibration procedure to facilitate imaging the nominal concentrations of tissue NADH and Fp in the mouse xenografts of two human melanoma lines, an indolent less metastatic A375P and a more metastatic C8161. Images of the redox indices (NADH, Fp, ORR) revealed the existence of more oxidized areas (OAs) and more reduced areas (RAs) within individual tumors. ORR was found to be higher and NADH lower in C8161 compared to that of A375P xenografts, both globally for the whole tumors and locally in OAs. The ORR in the OA can differentiate xenografts with a higher statistical significance than the global averaged ORR. H&E staining of the tumors indicated that the redox differences we identified were more likely due to intrinsically different cell metabolism, rather than variations in cell density.

Evaluation of Ce-MOFs as Photoanode Materials for the Water Oxidation Reaction: The Effect of Doping with [Ru(bpy)(dcbpy)(H2O)2]2+ Catalyst.

Artificial photosynthesis stands out as a highly effective method for harnessing sunlight to produce clean and renewable energy. The light-absorbing properties, chemical stability, and high redox activity of Ce-based metal-organic frameworks (MOFs) make them attractive materials for visible-light-driven water splitting. Currently, Ce-based MOFs remain a relatively underexplored system for photocatalytic water oxidation in acidic media. In this study, we synthesized a Ce-MOF with different linkers (1,4-benzenedicarboxylic acid, tetrafluoroterephthalic acid, 2-nitroterephthalic acid, 2,2'-bipyridine-5,5'-dicarboxylic acid, and 4,4'-biphenyldicarboxylic acid), which exhibit light-absorbing capability. Ce-based MOFs doped with [Ru(bpy)(dcbpy)(H2O)2]2+ (MOF-1 and MOF-2) water oxidation catalyst showed an enhanced photoelectrocatalytic current of ∼10-4 A·cm-2 at pH = 1, which is comparable with the [Ru(bpy)(dcbpy)(H2O)2]2+-doped MIL-126 Fe-based MOF. We also demonstrated the long-term durability of Ru-doped Ce-MOFs for photoelectrocatalytic water oxidation under acidic conditions. The as-synthesized MOFs were analyzed with powder X-ray diffraction (PXRD), Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), UV-visible diffuse reflectance spectroscopy, scanning electron microscopy (SEM), and electric conductivity measurements. This study contributes to the development of cost-effective materials for sustainable photocatalytic water splitting processes.

Enhanced charge separation via ZnIn2S4@S-doped-C3N4 S-scheme heterojunction for efficient photocatalytic water splitting under visible light

Heterojunction photocatalysts possess high efficiency in photogenerated electron-hole separation, which give significant advantages in the field of solar hydrogen production. Herein, a novel ZnIn2S4@S doped g-C3N4 (ZIS@SCN) heterojunction with mesoporous structure was prepared for photocatalytic water splitting under visible light. Characterization showed that the element of S was successfully introduced into g-C3N4 (CN) by replacing N to form C–S–C bonds and significantly enhanced the visible light absorption ability. The constructed heterojunction exhibited excellent photocatalytic hydrogen evolution under visible light. The best performance belonged to the sample of ZIS@100SCN. The corresponding H2 production rate reached 9.3 mmol h−1 g−1, which was 1.87-fold higher than that of the undoped one. More importantly, the heterojunction realized overall water splitting of H2 and O2 evolution simultaneously with good stability. The mechanism analysis indicted that introducing the element of S could regulate the band structure of CN and induce the charge transfer switching of a ZnIn2S4@g-C3N4 (ZIS@CN) photocatalyst from Ⅰ-type to S-scheme, which promoted the efficient spatial charge separation and maintained the high redox ability of the ZIS and SCN. This work provides an insight in construction high performance S-scheme heterojunction for water splitting with a doping method.

Conductive Metal-Organic Framework Grown on the Nickel-Based Hydroxide to Realize High-Performance Electrochemical Glucose Sensing.

Glucose holds significant importance in disease diagnosis as well as beverage quality monitoring. The high-efficiency electrochemical sensor plays a crucial role in the electrochemical conversion technology. Ni(OH)2 nanosheets are provided with high specific surface area and redox activity that are widely used in electrochemistry. Conductive metal-organic frameworks (cMOFs) perfectly combine the structural controllability of organic materials with the long-range ordering of inorganic materials that possess the characteristic of high electron mobility. Based on the above considerations, the combination of Ni(OH)2 and Ni-HHTP (HHTP=2,3,6,7,10,11-hexahydroxytriphenylene) as an electrode modification material is designed to enhance electrochemical performance. In this work, to improve glucose detection, a sequence of Ni(OH)2@NiCo-HHTP and NiM-LDH@Ni-HHTP (M=Co2+, Mn2+, Cu2+, LDH=layered double hydroxide) are successfully synthesised by doping metals into Ni-HHTP and Ni(OH)2, respectively. As a result, NiCu-LDH@Ni-HHTP showed the best excellent glucose detection sensitivity.

Protonated g-C3N4/oxygen-doped g-C3N4 S-scheme homojunction fabricated by electrostatic self-assembly for photocatalytic hydrogen evolution and tetracycline hydrochloride degradation

S-scheme photocatalytic systems with high redox ability and separation efficiency of photoexcited charge carriers supply considerable prospects for environmental optimization and sustainable energy development. However, coupling well-suited reduction and oxidation components for target reactions remains a challenge worth exploring. Herein, an efficient S-scheme system for H2 generation and tetracycline hydrochloride (TCH) photodegradation based on protonated g-C3N4 (PCN) coupling with oxygen-doped g-C3N4 (OCN) is fabricated via a facile electrostatic self-assembly strategy. Intimate interfacial interactions originating from the ultrathin nanostructure and staggered energy band arrangement for the S-scheme charge transfer pathway provide compelling advantages for the highly efficient separation of photoinduced electron-hole pairs in the as-designed PCN/OCN homojunction. The in-situ irradiated X-ray photoelectron spectroscopy (ISI-XPS) techniques and electron paramagnetic resonance (EPR) measurements are applied to confirm the successful construction and the validity of the S-scheme charge transfer pathway. The obtained PCN/OCN composites with optimal ratio achieve a decent H2 generation rate of 6184.7 μmol g−1 h−1 outpacing the single PCN by approximately 4.8-fold, and 90.5 % TCH photodegradation efficiency is also realized within 90 min. This work provides a delicate fresh round of elevation for the exploration of an effective photocatalytic system.

Polyaniline modified bimetallic hydroxide/ZIF composites as electrode materials for supercapacitors with high capacity and high stability

Metal-organic framework materials (MOFs) are widely used in electrochemical energy storage due to their abundant active sites and high redox activity. Especially in the field of supercapacitors, the porous structure of MOFs makes them the most promising candidates for composite electrode materials due to their vast specific surface area. However, the poor chemical stability of MOFs in alkaline electrolytes limits their application. Constructing and improving the stability of metal-organic backbone materials through rational structural design is the key to enhancing the electrochemical performance of capacitors. In this paper, the stability of ZIF-67 was enhanced by the complexing with bimetallic hydroxide (CoMn-LDH), and the conductivity is further enhanced by the mixing of polyaniline (PANI) to form a ``network structure'' morphology. As a result, the composite electrode material has a specific capacity of 1048 F g−1 at 1 A g−1 with a good cycle life (80.5 % capacity retention for 5000 cycles). The specific capacity of the CoMn-LDH/ZIF-67/PANI//AC asymmetric supercapacitor (ASC) was 164 F g−1 at 1 A g−1 in the voltage range of 0–1.5 V. The maximum energy density of the ASC was 51.25 Wh kg−1 at a power density of 2250 W kg−1. In addition, excellent cycling stability (71.2 % capacitance retention after 5000 cycles) was delivered.

Biotransformation of Pollutants by Pycnoporus spp. in Submerged and Solid-State Fermentation: Mechanisms, Achievements, and Perspectives

Substantial amounts of organo-pollutants, often persistent and toxic, are generated globally each year, posing a threat to soil, water, groundwater, and air. The pollutants encompass a wide range of substances from various sources, which include solid as well as liquid ones, such as landfill leachates and wastewaters. The compounds include paper and pulp mill byproducts, pharmaceuticals, diverse types of plastics, hydrocarbons, pigments, and dyes, as well as pesticides and insecticides. Fungal bioremediation stands out as a promising technology that uses the metabolic potential of fungi to eliminate or mitigate the impact of pollutants. Notably, species of the genus Pycnoporus exhibit significant capabilities for degrading a broad spectrum of toxic molecules. This degradation is facilitated by released ligninolytic enzymes, especially laccase, and cellular enzymes pertaining to the cytochrome P450 monooxygenase system. The laccase, which is overproduced by the genus Pycnoporus, is quite remarkable for its high redox potential. The objective of this review is to highlight the proficiency of the Pycnoporus genus in the degradation of pollutants in submerged and solid-state fermentation. Recent studies conducted over the past decade consistently highlight the Pycnoporus genus as a robust contender in the realm of white biotechnology.

Halide Exchange in Perovskites Enables Bromine/Iodine Hybrid Cathodes for Highly Durable Zinc Ion Batteries.

With the increasing need for reliable storage systems, the conversion-type chemistry typified by bromine cathodes attracts considerable attention due to sizeable theoretical capacity, cost efficiency, and high redox potential. However, the severe loss of active species during operation remains a problem, leading researchers to resort to concentrated halide-containing electrolytes. Here, profiting from the intrinsic halide exchange in perovskite lattices, a novel low-dimensional halide hybrid perovskite cathode, TmdpPb2[IBr]6, which serves not only as a halogen reservoir for reversible three-electron conversions but also as an effective halogen absorbent by surface Pb dangling bonds, C─H…Br hydrogen bonds, and Pb─I…Br halogen bonds, is proposed. As such, the Zn||TmdpPb2[IBr]6 battery delivers three remarkable discharge voltage plateaus at 1.21V (I0/I-), 1.47V (I+/I0), and 1.74V (Br0/Br-) in a typical halide-free electrolyte; meanwhile, realizing a high capacity of over 336 mAh g-1 at 0.4 A g-1 and high capacity retentions of 88% and 92% after 1000 cycles at 1.2 A g-1 and 4000 cycles at 3.2 A g-1, respectively, accompanied by a high coulombic efficiency of ≈99%. The work highlights the promising conversion-type cathodes based on metal-halide perovskite materials.

Thermodynamic and kinetic analysis on the biomass syngas fueled chemical looping hydrogen generation process in fixed bed reactor

Because of its simple structure and easy operation, the fixed bed reactor is widely used in the chemical looping process to assess the performance of oxygen carriers (OC) or to evaluate new chemical looping technologies. However, the systematic investigation of the redox behavior and temperature evolution during the chemical looping hydrogen generation (CLHG) process in the fixed bed reactor under different conditions, which is crucial for process optimization and reactor design, has received less attention. In the present work, the redox characteristics of the CLHG process with biomass syngas as the fuel in a fixed bed reactor were investigated and analyzed from a perspective of thermodynamics and kinetics. Results showed that high redox temperature (>800 °C) favors the fuel conversion due to the improved reaction kinetics and favorable thermodynamics. A space velocity in the range of 0.12–0.5 s−1 and superficial velocity of 0.008–0.075 m/s can provide enough reaction time meanwhile enhance the external diffusion of fuel gas, achieving high reduction degree of OC and further high H2 yield (3.4 mmol/g Fe2O3) and high H2 energy efficiency (45 %). Moreover, a violent OC bed temperature rise (100 °C) was observed in the air oxidization stage, which can be mitigated by diluting the Fe2O3 content and decreasing the air flow rate. Finally, the reaction front and flow front moving behavior were discussed in detail for a better understanding of the CLHG process.

Interfacial oxygen vacancy engineering and built-in electric field mediated Z-scheme In2O3/Ag3PO4 heterojunction for boosted photocatalytic doxycycline degradation

Doxycycline pollutants in environment seriously destroy the balance of ecological system. A Z-scheme In2O3/Ag3PO4 heterojunction is constructed by attaching Ag3PO4 nanoparticles on hollow In2O3 hexagonal prism structures for efficient degradation of doxycycline. The doxycycline (30 mg/L) removal rate by IAO-1 (mole ratio of In2O3:Ag3PO4 is 1:3, 1.0 g/L) reaches 99.7% under visible light irradiation. Degradation rates are almost unchanged after five cycles of degradation experiments, demonstrating the excellent reusability and stability of the IAO-1 photocatalyst. The photocatalytic degradation of doxycycline in different water matrices by IAO-1 shows excellent performance, which provides significant potential for practical applications. The experiments and DFT results demonstrate that the built-in electric fields in IAO-1 contribute to the charge transfer from Ag3PO4 to In2O3, leading to the formation of a Z-scheme heterojunction with high redox capacity. The hollow defect structure of IAO-1 effectively activates molecular oxygen to generate oxygen vacancies and induce 1O2 production through energy transfer, which promotes the attack of benzene rings and oxygen-containing groups in the molecular structure of doxycycline, leading to hydroxylation, demethylation, and ring-opening reactions. This work provides new ideas for constructing Z-scheme photocatalysts with oxygen vacancies and built-in electric fields for practical wastewater treatment.

High Entropy Alloys Enable Durable and Efficient Lithium-Mediated CO2 Redox Reactions.

Designing electrocatalysts with high activity and durability for multistep reduction and oxidation reactions is challenging. High-entropy alloys (HEAs) are intriguing due to their tunable geometric and electronic structure through entropy effects. However, understanding the origin of their exceptional performance and identifying active centers is hindered by the diverse microenvironment in HEAs. Herein, NiFeCoCuRu HEAs designed with an average diameter of 2.17 nm, featuring different adsorption capacities for various reactants and intermediates in Li-mediated CO2 redox reactions, are introduced. The electronegativity-dependent nature of NiFeCoCuRu HEAs induces significant charge redistribution, shifting the d-band center closer to Fermi level and forming highly active clusters of Ru, Co, and Ni for Li-based compounds adsorptions. This lowers energy barriers and simultaneously stabilizes *LiCO2 and LiCO3+CO intermediates, enhancing the efficiency of both CO2 reduction and Li2CO3 decomposition over extended periods. This work provides insights into specific active site interactions with intermediates, highlighting the potential of HEAs as promising catalysts for intricate CO2 redox reactions.