Bimetallic Systems Research Articles

Enantioselective Pd- and Cu-Catalyzed Hydrofunctionalization of Methylenecyclopropanes via a Distal C-C Bond Cleavage.

The enantioselective ring-opening reactions of methylenecyclopropanes (MCPs) involving C-C bond activation via oxidative addition of transition metals have been rarely reported. Here, we disclose a Pd/Cu-catalyzed enantio- and regioselective coupling between cyclic imino esters and MCPs to produce α-allylated 2H-pyrrole derivatives. In this reaction, azomethine ylide formed by a chiral copper catalyst with ketimine ester would serve as a nucleophile to react with activated MCPs via palladium catalysis. This bimetallic catalyst system exhibited a broad substrate scope and high regio- and enantioselectivities.

A pH/GSH Dual-Responsive Triple Synergistic Bimetallic Nanocatalyst for Enhanced Tumor Chemodynamic Therapy.

Chemodynamic therapy (CDT) has garnered significant attention in the field of tumor therapy due to its ability to convert overexpressed hydrogen peroxide (H2O2) in tumors into highly toxic hydroxyl radicals(•OH) through metal ion-mediated catalysis. However, the effectiveness of CDT is hindered by low catalyst efficiency, insufficient intra-tumor H2O2 level, and excessive glutathione (GSH). In this study, a pH/GSH dual responsive bimetallic nanocatalytic system (CuFeMOF@GOx@Mem) is developed by modifying red blood cell membranes onto glucose oxidase (GOx)-loaded Fe-Cu bimetallic MOFs, enhancing the efficacy of CDT through a triple-enhanced way by H2O2 self-supply, catalysts self-cycling, and GSH self-elimination. Upon accumulation in tumor tissues facilitated by the red blood cell membrane, the GOx initiates a reaction with glucose to generate H2O2 and gluconic acid in situ. Subsequently, the reduced pH triggers the release of Fe3+ and Cu2+ from CuFeMOF@GOx@Mem, which is immediately turned into Fe2+ and Cu+ by GSH, activating the Fe2+-mediated Fenton reaction. More importantly, Cu+ can also act as an accelerator of Fe3+/Fe2+ conversion, meanwhile, the generated Cu2+ can be further reduced to Cu+ by GSH. Consequently, sustained accumulation of H2O2 and Fe2+ as well as sustained elimination of GSH are achieved simultaneously, providing a unique approach for improving the anti-tumor ability of CDT.

Intrinsic Coexistence of Miscibility and Segregation in Gold-Silver Nanoalloys.

Bimetallic nanoparticles are used in numerous applications in catalysis, plasmonics or fuel cell technology. The addition of the second metal to the nanoparticles allows enhancing and fine-tuning their properties by choosing their composition, size, shape and environment. However, the crucial additional parameter of chemical structure within the particle is difficult to predict and access experimentally, even though segregated core-shell structures and random alloys can have drastically different physicochemical properties. This is highlighted by the vast literature on the most studied bimetallic system, gold-silver, for which the controversy on whether gold and silver are miscible on the nanoscale or segregate persists. Here, these contradictions are solved by determining quantitatively the coexistence of an alloyed core and a 1-2nm thick shell with gradual silver enrichment as the chemical ground state structure. Chemical reactions with the environment and meta-stable structures are furthermore identified as responsible for the contradictions in the literature. This method is applicable to other multi-metallic systems, provides benchmark input for theoretical models, and forms the basis for studying chemical rearrangements under reactive conditions in catalysis.

Assembling Di- and Polynuclear Cu(I) Complexes with Rigid Thioxanthone-Based Ligands: Structures, Reactivity, and Photoluminescence.

Thioxanthone (TX) molecules and their derivatives are well-known photoactive compounds. Yet, there exist only a handful of luminescent systems combining TX with transition metals. Recently, we reported a TX-based PSP pincer ligand (L1) that appears as a promising platform for filling this niche. Herein, we demonstrate that with Cu(I) this ligand exclusively assembles into dimeric structures with either di- or polynuclear Cu(I) cores. With cationic Cu(I) precursors, complexes featuring solvent-bridged bis-cationic cores were obtained. These coordinatively unsaturated bimetallic systems showed surprisingly facile activation of the chloroform C-Cl bonds, suggesting a possible metal-metal cooperation. The reaction of L1 with binary Cu(I) halides afforded dimeric complexes with polynuclear [CuX]n (n = 3 or 4) cores. With X = Br or I, emissive complexes containing stairstep [CuX]4 clusters were obtained. Emission lifetimes in the microsecond range measured for these complexes were indicative of a triplet emission (phosphorescence), which according to our time-dependent density functional theory study originates from a halide-metal-to-ligand charge transfer between the [CuX]4 cluster and the TX backbone of L1. Finally, the distinctive polynucleating behavior of L1 toward Cu(I) was also showcased by a comparison to another PSP ligand with a diaryl thioether backbone (L2), which formed only mononuclear pincer-type complexes, lacking any unusual reactivity or photoluminescence.

Decoupling Intrinsic Metal Ion Reduction Rates from Structural Outcomes in Multimetallic Nanoparticles.

Simultaneously controlling both stoichiometry and atom arrangement during the synthesis of multimetallic nanoparticles is often challenging, especially when the desired metal precursors exhibit large differences in their intrinsic reduction kinetics. In such cases, traditional synthetic methods often lead to the formation of exclusively phase-segregated structures. In this study, we demonstrate that the relative reduction kinetics of the metal precursors can be manipulated independently of their intrinsic differences in reduction rates by modulating the instantaneous concentrations of the metal cation precursors. We achieve this control by adjusting the precursor addition rate, which decouples chemical ordering outcomes from differences in precursor reduction kinetics. To guide these experiments, we describe a quantitative model to determine how metal ion reduction rates evolve with variations in the precursor addition rate and thereby predict optimal conditions for the synthesis of multimetallic nanoparticles with precise structural and compositional outcomes. We demonstrate the efficacy of this model experimentally by synthesizing both core@shell and alloyed nanoparticles with stoichiometric control using the same metal ion precursors in two different bimetallic systems (Au-Pd and Au-Pt) as well as in a quinary metal system (Co, Ni, Cu, Pd, and Pt). This approach enables the design of nanoparticle architectures independent of intrinsic differences in metal ion reduction potentials of the constituent metals while maintaining both stoichiometric and structural control.

Cathodic Corrosion-Induced Structural Evolution of CuNi Electrocatalysts for Enhanced CO2 Reduction

Article Cathodic Corrosion-Induced Structural Evolution of CuNi Electrocatalysts for Enhanced CO2 Reduction Wenjin Sun 1,†, Bokki Min 2,†, Maoyu Wang 3, Xue Han 4, Qiang Gao 1, Sooyeon Hwang 5, Hua Zhou 3, and Huiyuan Zhu 1,2,* 1 Department of Chemistry, University of Virginia, Charlottesville, VA 22904, USA 2 Department of Chemical Engineering, University of Virginia, Charlottesville, VA 22904, USA 3 Advanced Photon Source, Argonne National Laboratory, Lemont, IL 60439, USA 4 Department of Chemical Engineering, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA 5 Center for Functional Nanomaterials, Brookhaven National Laboratory, Upton, NY 11973, USA * Correspondence: kkx8js@virginia.com † These authors contributed equally to this work. Received: 22 October 2024; Revised: 25 November 2024; Accepted: 27 November 2024; Published: 4 December 2024 Abstract: The electrochemical CO2 reduction reaction (CO2RR) has attracted significant attention as a promising strategy for storing intermittent energy in chemical bonds while sustainably producing value-added chemicals and fuels. Copper-based bimetallic catalysts are particularly appealing for CO2RR due to their unique ability to generate multi-carbon products. While substantial effort has been devoted to developing new catalysts, the evolution of bimetallic systems under operational conditions remains underexplored. In this work, we synthesized a series of CuxNi1−x nanoparticles and investigated their structural evolution during CO2RR. Due to the higher oxophilicity of Ni compared to Cu, the particles tend to become Ni-enriched at the surface upon air exposure, promoting the competing hydrogen evolution reaction (HER). At negative activation potentials, cathodic corrosion has been observed in CuxNi1−x nanoparticles, leading to the significant Ni loss and the formation of irregularly shaped Cu nanoparticles with increased defects. This structural evolution, driven by cathodic corrosion, shifts the electrolysis from HER toward CO2 reduction, significantly enhancing the Faradaic efficiency of multi-carbon products (C2+).

Degradation of the Antibiotic Sulfamethoxazole by Ozonation: A Comprehensive Review

ABSTRACTSulfamethoxazole (SMX) is an antibiotic widely used for the treatment of several diseases, especially respiratory and urinary. Due to its widespread use, its presence in the environment has been on the rise. This study discusses the degradation of the antibiotic SMX through the ozonation process. SMX is preferentially degraded by the direct action of O3 on the molecule, starting by breaking the double bonds in the aromatic ring. Through ozonation it is possible to obtain complete SMX degradation within 10 min, but the mineralization of the solution is not achieved, reaching total organic carbon removal efficiencies of 5%–60%, depending on the reaction time. Factors such as the presence of organic matter (OM) and the pH of the solution interfere with the degradation of SMX. The OM acts as a radical scavenger, decreasing the efficiency of degradation, while the pH interferes with the decomposition of O3 into radicals and the dissolution of the oxidant in the medium, in addition to influencing the state of ionization of the SMX making it more or less prone to reactions. In general, most other remediation processes are carried out on a laboratory scale. To increase the level of these processes to a full scale, more pilot‐scale studies are needed. In addition, it is necessary to focus on the practice of reusing materials, avoiding the generation of secondary pollution, and increasing the useful life of the material. The review also discusses the reaction mechanisms, intermediate compounds formed, mineralization of the solution, and factors that influence the process, which can help in making decisions for future studies to be carried out in the area. Prospects in the research area revolve around using metal–organic frameworks as molecular imprinting technology to modify heterogeneous catalysts, integration of external energy, bimetallic systems, and evaluation of deactivation mechanisms.

Continuous peroxymonosulfate activation by a novel CoFe2O4-functionalized carbon fiber electroactive filter towards ultrafast and cost-effective decontamination: Performance, mechanism and application

Constructing an integrated electrochemical filtration system for flow-through electrocatalytic peroxymonosulfate (PMS) activation presents an efficient strategy for treating wastewater containing organic micropollutants. However, there remains a deficiency of feasible and cost-effective flow-through systems for practical applications. Herein, we developed a novel electroactive CoFe2O4-functionalized carbon fiber filter (CoFe2O4/CFF) to activate PMS towards ultrafast and cost-effective degradation of sulfamethoxazole (SMX). CoFe2O4 nanoparticles were uniformly loaded onto the surface of carbon fiber by hydrothermal synthesis, resulting in a diameter of 110.6 ± 26.3 nm. Under optimal conditions, SMX was degraded 98.0 % in a single-pass through the CoFe2O4/CFF. The system exhibited robust performance across complicated matrices (e.g., tap water and lake water), a variety of micropollutants (75.4–98.0 %) and especially over a broad initial pH range (3 − 10). We identified the reaction pathways involving reactive oxygen species (1O2, SO4∙- and •OH) and high-valence metals, which collectively facilitated the efficient degradation of pollutants within the system. Theoretical calculations further confirmed that the Co-Fe bimetallic system in CoFe2O4 exhibited significant synergistic effects, consistent with experimental findings. The system’s superior catalytic performance can be attributed primarily to convection-enhanced mass transfer from the flow-through design and to the improved catalytic activity and robustness of CoFe2O4 catalysts, driven by accelerated redox cycles of Co3+/Co2+ and Fe3+/Fe2+ due to the applied cathode potential. Benefiting from the integration of electrochemistry, the proposed catalytic filtration system demonstrated strong anti-fouling properties. Detailed calculations and comparative analyses substantiated the cost-effectiveness of this system. Therefore, the electroactive CoFe2O4/CFF-based flow-through electrocatalytic PMS activation system offers a unique and economically viable approach for the efficient and ultrafast remediation of sulfamethoxazole.

Discovering the Catalytic Role of Interfacial Water Towards Hydrogen Evolution/Oxidation Reactions in Aqueous Solutions

Despite significant research efforts, the sluggish kinetics of the hydrogen evolution and oxidation reactions (HER/HOR) on Pt in alkaline solutions remain poorly understood. The role of interfacial water molecules has been investigated in recent years, yet several questions persist. These include a clear definition of interfacial water molecules, their distinction from bulk or hydrated water, and their specific mechanism of action in HER/HOR processes. Addressing these questions is critical for unraveling the HER/HOR interface and will inform the development of next-generation catalysts for green hydrogen. Herein, we explore the HER/HOR kinetics of various catalysts, including monometallic (Pt, Ru, Pd) and bimetallic (Pt-Ru) systems, in alkaline electrolytes (AMOH, where AM represents alkali metal cations) at different pH levels. Our findings indicate that HER/HOR kinetics are consistently slower in 0.01M AMOH (pH 12) than in 0.1M AMOH (pH 13), a trend that current pH-based theories do not explain. Using high energy resolution fluorescence detection X-ray absorption spectroscopy (HERFD-XAS) and attenuated total reflectance-surface enhanced infrared adsorption spectroscopy (ATR-SEIRAS), we identified two distinct behaviors of interfacial water across the catalysts. In dilute electrolytes (0.01M), the interfacial water demonstrates reduced flexibility, hindering the transport of HER/HOR intermediates. Conversely, in concentrated electrolytes (0.1M), interfacial water supports the HER/HOR process via a bifunctional pathway and obey the hard-soft acid-base (HASB) interaction. Slow-growth sampling coupled with ab initio molecular dynamics (SG-AIMD) simulations corroborate that the hydrogen bonding network in 0.01M electrolyte is less conducive to reactivity compared to that in 0.1M electrolyte. Our results aid existing theories and provide new insights into the fundamental mechanisms of alkaline HER/HOR catalysis. Acknowledgement The authors thank the funding source from Liquid Sunlight Alliance under the U.S. DOE, Office of Science, Office of Basic Energy Sciences, Fuels Award Number DE-SC0021266 and the Laboratory Directed Research and Development Program of the Lawrence Berkeley National Laboratory under the U.S. DOE Contract No. DE-AC02-05CH11231. This research used beamline 8-ID (ISS) of the National Synchrotron Light Source II, a U.S. Department of Energy (DOE) Office of Science User Facility operated for the DOE Office of Science by Brookhaven National Laboratory under Contract No. DE-SC0012704.

Ligand‐Directed Assembly of Multimetallic Aluminum Complexes: Synthesis, Structure and ROP Catalysis

AbstractMultinuclear aluminum complexes are useful catalysts for the ring opening polymerization (ROP) of ϵ‐caprolactone (ϵ‐CL), often outperforming monometallic analogues in the production of biodegradable polycaprolactone (PCL). These complexes require control over metal‐metal distance, ligand structure, and substituents. Herein, we report on the preparation of mono‐, bi‐, and octametallic aluminum complexes through direct chelation of multidentate bis(phosphino)‐2,2‐dimethyl‐1,3‐diamino ligands Me2C[CH2NHR2P(O)]2; R=Ph(1), iPr(2), tBu(3). Ligands 1–3 yielded bimetallic complexes with two types of coordination pockets, as well as bimetallic systems with identical coordination environments. In addition to the diversity of structural patterns within the present series, the catalytic performances of [AlR2{κ2‐N,N’,–(Me2C{CH2NPh2P(O)}2}‐(κ2‐O,O’‐AlR2)] (R=Me(4), Et(5), iBu(6)) outperformed that of the monometallic [AlEt2{κ2‐O,O’‐(Me2C(CH2NtBu2P(O))2H} (10), showing controlled and immortal ROP of ϵ‐CL in the presence of BnOH as co‐initiator. DFT calculations suggest that the primary active site for 4–6 is the N−Al–N center. Gaining insight into the underlying principles that lead to high activity and controlled production of PCL in bimetallic systems can help design tailor‐made complexes with enhanced performance.

Synergistic Palladium/Silver/Ligand Catalysis for C−H Alkenylation of 2,1,3‐Benzofused Heterodiazoles

AbstractThe combination of palladium and silver complexes has emerged as a bimetallic catalytic system in C−H activation, frequently outperforming palladium‐only systems. Beyond the conventional roles of silver (I) salts serving as oxidants, halide scavengers, and Lewis acids, Pd−Ag bimetallic synergism has been shown to facilitate C−H cleavage. In this study, we explore the incorporation of a pyrazolopyridone (PzPyOH) ligand into a Pd−Ag bimetallic catalytic system, which together promote both C−H cleavage and migratory insertion processes. This synergistic approach enables dehydrogenative C−H alkenylations at the C4 position of 2,1,3‐benzothiadiazole, 2,1,3‐benzoxadiazole, and 2,1,3‐benzotriazole with alkenes. These results demonstrate the potential of combining novel ligands with heterobimetallic systems to facilitate other elementary steps beyond C−H cleavage, suggesting their broader applicability in C−H functionalization.

Dual Au/Ag Catalyzed Regiospecific Intramolecular Hydroacyloxylation and Hydroalkoxylation of Unactivated Geminal-Substituted Olefins.

A mild, regiospecific Gold-Silver bimetallic catalytic system has been devised for the intramolecular hydroacyloxylation and hydroetherification of alkenoic acids and alcohols. This method exhibits precise specificity for the geminal substituted olefinic center and facilitates the synthesis of substituted phthalide and hydroisocoumarin derivatives. This method has been effectively applied for late-state functionalization to produce bioactive natural products such as rumphellaone A, mycophenolate, and (-)-ambrox. The successful gram-scale synthesis of the anticonvulsant, hypnotic drug (±)-ethyl phenyl butyro lactone (EPBL), (±)-Boivinianin A and the ability to synthesize challenging spiro and bicyclic lactone underscores the synthetic potential of this methodology. Mechanistic insights into gold-silver catalyzed lactonization of olefins have also been discussed.

Continuous-flow mechanochemical preparation of Ag-Cu@ZIF-8 bimetallic system for antimicrobial applications

This study discloses the synthesis of Ag- and Cu- modified ZIF-8 materials using a novel, sustainable beads-assisted flow reaction in a continuous-flow mechanochemical system. This approach offers an efficient, environmentally friendly route to producing antimicrobial materials with promising applications. Antimicrobial tests against Escherichia coli, Staphylococcus aureus, and Candida albicans revealed that pristine ZIF-8 showed no relevant biological activity. Ag@ZIF-8 comparably demonstrated strong bactericidal activity against E. coli and S. coli at 0.1 mg mL-1, while Cu@ZIF-8 exhibited moderate antibacterial activity against S. aureus (0.5 mg mL-1, 5% Cu loading) and no activity against E. coli or C. albicans. Notably, bimetallic Ag-Cu@ZIF-8 composite (5% Ag + 5% Cu) displayed enhanced antibacterial efficacy including antifungal activity against C. albicans at a concentration of 0.1 mg mL-1, likely due to a synergistic effect between Ag and Cu ions.

Platinum‐Group Metal High‐Entropy Selenides for the Hydrogen Evolution Reaction

AbstractThe selenides of platinum‐group metals (PGMs) are emerging as promising catalysts for diverse electrochemical reactions. To date, most studies have focused on single metal or bimetallic systems, whereas the preparation of a high‐entropy (HE) selenide consisting of five or more PGM elements holds the promise to further enhance catalytic performance by introducing abundant active sites with various local coordination environments and electronic structures. Herein, we report for the first time the synthesis of PGM‐based HE‐Selenide (HE‐Se) nanoparticles with a unique amorphous structure. The atomic metal–Se coordination and the presence of short‐range order were thoroughly revealed. It is further shown that the amorphous HE‐Se can be facilely transformed into a single‐phase crystalline HE‐Se with a cubic structure by thermal annealing. Catalytically, the amorphous HE‐Se showed better acidic hydrogen evolution activity over monometallic PGM‐based selenides and the crystalline counterpart, demonstrating the advantages of high‐entropy configuration and amorphous structure. Our findings may pave the way toward the synthesis and property exploration of amorphous PGM‐based selenides with tunable compositions.

Platinum-Group Metal High-Entropy Selenides for the Hydrogen Evolution Reaction.

The selenides of platinum-group metals (PGMs) are emerging as promising catalysts for diverse electrochemical reactions. To date, most studies have focused on single metal or bimetallic systems, whereas the preparation of a high-entropy (HE) selenide consisting of five or more PGM elements holds the promise to further enhance catalytic performance by introducing abundant active sites with various local coordination environments and electronic structures. Herein, we report for the first time the synthesis of PGM-based HE-Selenide (HE-Se) nanoparticles with a unique amorphous structure. The atomic metal-Se coordination and the presence of short-range order were thoroughly revealed. It is further shown that the amorphous HE-Se can be facilely transformed into a single-phase crystalline HE-Se with a cubic structure by thermal annealing. Catalytically, the amorphous HE-Se showed better acidic hydrogen evolution activity over monometallic PGM-based selenides and the crystalline counterpart, demonstrating the advantages of high-entropy configuration and amorphous structure. Our findings may pave the way toward the synthesis and property exploration of amorphous PGM-based selenides with tunable compositions.

Biosorption of Pb2+, Cd2+ and Zn2+ from aqueous solutions by Agrobacterium tumefaciens S12 isolated from acid mine drainage

Heavy metal pollution is a global environmental issue, and microorganisms play a crucial role in the bioremediation of heavy metal-contaminated wastewater. The study isolated heavy metal-resistant bacterium and observed their absorption ability toward Pb2+, Cd2+ and Zn2+. We isolated Agrobacterium tumefaciens S12 from acid mine drainage. The various factors influencing its adsorption performance, including pH, biomass dosage, initial metal ion concentration, and adsorption temperature, were investigated in detail. Chemisorption controls the adsorption rate due to the results better fitted by pseudo-second order kinetics. The maximum adsorption capacities of Pb2+, Cd2+ and Zn2+ on A. tumefaciens S12 were 234, 58 and 51 mg g−1 at 30 °C from Langmuir isotherm, respectively. The adsorption processes for the three heavy metal ions were spontaneous and exothermic in nature. In bimetallic systems, biosorption of Pb2+ ions was preferential to that of Cd2+ and Zn2+. Furthermore, scanning electron microscopy coupled to energy dispersive spectroscopy, Fourier-transform infrared spectra and X-ray photoelectron spectroscopy analysis demonstrated that the adsorption mechanisms include ion-exchange, complexation interaction between the heavy metal ions and the functional groups on the surface of biomass. The obtained results indicated that A. tumefaciens S12 can be applied as an efficient biosorbent in bioremediation technology to sequestrate heavy metal ions from aqueous solution.

Preparation of conductive bimetallic phthalocyanine with acceptor and their electrocatalytic properties for CO2 reduction

Abstract In order to develop a catalyst for electrochemical CO2 reduction with high power efficiency, we prepared molecular crystals with 2 types of metal phthalocyanine. Charge transfer complexes with acceptor were selected as the molecular crystal system to reduce the electrical resistance. Various bimetallic phthalocyanine systems consisting of cobalt phthalocyanine and another metal phthalocyanine were obtained as highly conductive separated stacked charge transfer complexes with iodine as an acceptor. The obtained catalysts for CO2 reduction were evaluated using gas diffusion electrodes. The catalysts containing the bimetallic phthalocyanine system of cobalt and copper phthalocyanines showed higher CO2 reduction current and higher CO production, indicating that the CO2 reduction on cobalt phthalocyanine is enhanced by the H2 formation reaction on copper phthalocyanine.

Unveiling multimodal hot carrier excitation in plasmonic bimetallic Au@Ag nanostars for photochemistry and SERS sensing

Plasmonic nanostructures stand at the forefront of nanophotonics research, particularly in sensing and energy conversion applications. Their unique ability to confine light energy at the nanoscale makes them indispensable for a wide array of technological advancements. The study of these structures often makes use of different materials and, even more extensively, explores new shapes and configurations to extend our common repertoire of useful nanophotonics tools. Exploring the creation of bimetallic plasmonic nanostructures combines these two dimensions determining the space of possible plasmonic resonators and opens the possibility of tailoring systems with behavior unavailable to single-metal plasmonic structures. In this paper, we delve into the exploration of bimetallic systems employing plasmonic nanostars. These structures have demonstrated remarkable capabilities for surface-enhanced Raman scattering (SERS) spectroscopy and photochemistry, due to the strong plasmonic response of their peaks, whose disposition following a spherical symmetry makes them largely polarization- and orientation-insensitive. Herein, we report the colloidal synthesis of two different water-stable Au@Ag nanostars, explore their performance as photocatalysts and SERS substrates, and provide an in-depth account of their non-trivial physical response.

Boosted direct electrochemical reduction of As(III) from arsenic wastewater via Cu(II)-assisted codeposition on a CuIn alloy electrode

Arsenic contamination is a severe environmental problem. A promising strategy for addressing this issue is the direct conversion of highly toxic As(III) to less toxic elemental arsenic (As(0)) using electrochemical reduction technology. In this study, a novel CuIn alloy nanoparticles-modified copper foam (CuIn NPs/CF) was prepared as an efficient cathode for the electrocatalytic reduction of highly mobile As(III) to solid As(0). Density functional theory (DFT) results revealed that the Cu-In bimetallic system exhibited weaker H atom bonding, and the Cu-ln surface was more favorable for the adsorption of *AsO₃ species than the Cu surface. Compared to the pristine CF electrode, CuIn NPs/CF was demonstrated to effectively suppressed the hydrogen evolution reaction with an enlarged hydrogen evolution potential of 1.45 V, and displayed a superior As(0) recovery yield. The conversion of As(III) to As(0) was further enhanced by adding Cu²⁺ to the electrolyte, facilitating a Cu-As co-deposition process. Notably, the CuIn NPs/CF electrode achieved an As(0) recovery yield of 5.38 mg cm⁻² after eight successive recycling tests. This work not only presents a green and sustainable strategy for As(III) removal, but also provides valuable insights into the rational design of Cu-based alloy cathodes for electrocatalytic reduction.

Fe/Mo bimetallic synergy system for ultra-highly efficient degradation of Rhodamine B

The traditional Fenton process, which depends on the use of Fe2+/H2O2, is constrained by the consumption of ferrous ions and the requirement for large amounts of H2O2. However, the assembly of bimetallic synergy systems with adjustable valence metal cations and enhanced dispersion of active sites has been evidenced to address these limitations. In this work, the Fe/Mo bimetallic synergy system in FexMo-CN materials is explored, utilized for the degradation of dyes with the assistance of H2O2. The cooperative effect of Fe/Mo bimetallic and the highly dispersed FeMoO4 as active sites make materials to achieve ultra-highly efficient degradation of dyes, approximately 100 % Rhodamine B (RhB) degradation within 6 min. And the corresponding degradation rate constant is 1.3471 min−1. Additionally, FexMo-CN materials exhibit excellent stability and versatility in solutions containing various cations, anions, or other dyes. Quenching experiments and EPR tests demonstrate that singlet oxygen (1O2) serves as the main reactive oxygen species (ROS) to degrade RhB. And the mechanism of generated 1O2 is revealed. The degradation path and mechanism of RhB are analyzed and the toxicology of intermediate products are calculated in detail. This work presents a novel approach for enhancing efficiency in Fenton-like reactions within the field of environmental remediation.