3D Metal Research Articles

Ferrocene-based 2D metal–organic framework nanosheet for highly efficient photocatalytic seawater uranium recovery

Sustainable uranium supply is critical for the long-term development of nuclear energy. The photocatalytic reduction of soluble hexavalent uranium to insoluble tetravalent uranium using photocatalysts has been recognized as a highly promising method for uranium recovery. However, existing photocatalysts face limitations such as restricted visible-light absorption and poor charge transfer capability, which hinder their photocatalytic uranium recovery performance. In this work, 1,1′-ferrocene dicarboxylic acid (FcDA) was introduced to synthesize the photocatalyst Zr-Fc-MOF3. The incorporation of FcDA broadened the visible light absorption range and reduced the band gap of Zr-Fc-MOF3, thereby enhancing electron-hole pair separation and carrier transport efficiencies. Moreover, the two-dimensional (2D) nanosheet structure of Zr-Fc-MOF3 provided a large surface area, allowing full exposure of active sites. Additionally, Fe(II) in FcDA generated photoelectrons upon light excitation to facilitate uranium reduction, and the recyclable redox behavior of Fe(II) conferred high reusability of the photocatalyst. Consequently, Zr-Fc-MOF3 demonstrated a high photocatalytic uranium recovery capacity of 8.29 mg g−1 over 10 days in natural seawater (NSW), with a uranium recovery rate of 0.829 mg g−1 d−1, surpassing most other photocatalysts applied in NSW. These findings suggest that designing 2D nanosheet materials with ligands capable of efficient photoelectron generation is a promising approach for developing high-performance uranium recovery photocatalysts.

The crystal engineering of 3d-metal with two tetrazole-phenyl-carboxylate linkers and multiple post-synthetic metal exchange

Ligand with mixed-groups contributes to the construction of special structure motif with novel properties, yet it is challenging to understand and regulate the competitive coordination of different functional groups toward metal ions. Herein, the crystal engineering for MOF construction from two linear di-topic linkers of 4-(1H-tetrazol-5-yl)benzoic acid (H2tzba) and the longer 4′-(1H-tetrazol-5-yl)-[1,1′-biphenyl]-4-carboxylic acid (H2tzbba) featuring dual groups of phenyl-carboxylate and tetrazole, with three typical 3d metal ions (Mn2+, Fe2+ and Zn2+) were investigated. A series of five new MOFs, that are [Mn3(tzba)3(dmf)4]·11dmf (1, dmf = N,N-Dimethylformamide), [Mn(tzba)(H2O)] (2), [Zn2(tzba)2(dmf)]·0.5dmf (3), [Fe2(tzba)2(dmf)]·0.5dmf (4) and [Zn2(tzbbz)(gac)(dmf)2]·1.5dmf (5), were synthesized under solvothermal reactions. The modified solvent template and temperature effects lead to 3D framework of 1 (dmf solution under 433 K) with [Mn3(tz)3(COO)3] nodes and 1D hexagonal channels, while the 2 (water solution under 373 K) posssesses compact pillared-layer motif from [Mn2(tz)2] nodes. Under changed metal salt reactents but same solvent of dmf, the generated 3 and 4 have isoreticular and porous pillared-layer structure constituted of [M2(COO)2] nodes. The use of tzbba coupled with a crucial auxiliary ligand of glycollic acid, leads to 5 as porous pillared-layer MOFs with 1D rounded channels. The porous flexible skeleton of 1 constructed from [Mn3] node with four coordinated dmf facilitates post-synthetic metal exchange of the Mn2+ by radius similar metal ions following priority of Cu2+ < Zn2+ < Ni2+< Co2+, with maximum exchange percentage ranging from 17 % to 69 %. Time dependent ICP-AES analysis revealed the quite wide feasible solvents for post-synthetic metal exchange, as well as the fine control on substituting degree based on soaking temperature and time. Particularly, the compatible introduce of four different metal ions support the potential of preparing bi-, tri-, tetra- and penta- metal MOF crystals, that can not be obtained by traditional solvothermal reactions.

High-performance deep learning segmentation for non-destructive testing of X-ray tomography

For non-destructive testing (NDT) with X-ray computed tomography (XCT), the complex morphological segmentation of homogeneous defects is impossible for traditional threshold-based segmentation algorithm, due to their same absorbances. A variety of defect segmentation using convolutional neural networks (CNNs) has been suitable for such problems, and its accuracy is determined by image quality and comprehensiveness of training set. To achieve a high-performance measurement for quantitative defect evaluation, a modified U-Net-based segmentation model of XCT was proposed suitable for defects with various image quality resulting from different experimental efficiency. The dataset consisting of 24 subsets was acquired from the condition-varying measurements of aluminum alloy samples produced by laser 3D metal printing additive manufacturing. The structure and distribution of segmented pore and crack defects were accurately visualized by our model. Compared with traditional and main CNNs-based segmentation methods, our model exhibited a better recognition accuracy for pores and cracks, the Mean Intersection over Union and Pixel accuracy metrics reaching to 84.83 % and 98.87 % respectively. Practically, the option of efficiency or accuracy priority was quantitatively determined to carry out such a high-performance defect-related NDT. The proposed XCT-based segmentation mode has a great potential in fields of engineering, material science, biomedicine.

Revisiting Sub-Band Gap Emission Mechanism in 2D Halide Perovskites: The Role of Defect States.

Understanding the sub-band gap luminescence in Ruddlesden-Popper 2D metal halide hybrid perovskites (2D HaPs) is essential for efficient charge injection and collection in optoelectronic devices. Still, its origins are still under debate with respect to the role of self-trapped excitons or radiative recombination via defect states. In this study, we characterized charge separation, recombination, and transport in single crystals, exfoliated layers, and polycrystalline thin films of butylammonium lead iodide (BA2PbI4), one of the most prominent 2D HaPs. We combined complementary defect- and exciton-sensitive methods such as photoluminescence (PL) spectroscopy, modulated and time-resolved surface photovoltage (SPV) spectroscopy, constant final state photoelectron yield spectroscopy (CFSYS), and constant light-induced magneto transport (CLIMAT), to demonstrate striking differences between charge separation induced by dissociation of excitons and by excitation of mobile charge carriers from defect states. Our results suggest that the broad sub-band gap emission in BA2PbI4 and other 2D HaPs is caused by radiative recombination via defect states (shallow as well as midgap states) rather than self-trapped excitons. Density functional theory (DFT) results show that common defects can readily occur and produce an energetic profile that agrees well with the experimental results. The DFT results suggest that the formation of iodine interstitials is the initial process leading to degradation, responsible for the emergence of midgap states, and that defect engineering will play a key role in enhancing the optoelectronic properties of 2D HaPs in the future.

Development of hybrid landing gear for OMOTENASHI surface probe

This study presents technologies of the triple hybrid landing gear for the OMOTENASHI(Outstanding Moon exploration Technologies demonstrated by Nano Semi-Hard Impactor) spacecraft, which consists of an airbag, a crushable material as a shock absorber, and an impact resistance structure. The inflated airbag has capability to possibly mitigate impact acceleration at the instant of landing and submergence into regolith that covers a planetary surface. The crushable material with lattice structures, manufactured by a metal 3D printer, serves a dual purpose: it dissipates kinetic energy and controls the impact acceleration at landing by compressing itself within a designed deceleration distance. Further, in the impact resistance structure, the protective object is filled with resin and hollow glass beads, and the impact resistance is improved while the weight reduction is maintained. This paper provides the technical details such as the required specification, verification test results, and assembly result of the surface probe as the smallest lander of the OMOTENASHI spacecraft.

Double Perovskite Interlayer Stabilized Highly Efficient Perovskite Solar Cells.

Metal halide perovskite solar cell (PSC) technology has an impressive power conversion efficiency (PCE) exceeding 26.1% and demonstrates cost-effective manufacturing. However, the stability of these PSCs poses a significant challenge, hindering their widespread manufacturing and commercialization. To tackle the degradation issue inherent in PSCs, surface passivation techniques, particularly employing a thin layer of two-dimensional (2D) perovskites, create a 2D/3D heterostructure. Beyond this, the exploration of metal halide double perovskites adds a new dimension to the chemical and band gap phase space of materials for optoelectronic applications. In this study, we leverage a wide band gap double perovskite interlayer to enhance the stability of 3D metal halide perovskite. Specifically, the double perovskite nanoparticle Cs2AgBiBr6, with its substantial band gap of 2.2 eV and exceptional air stability, is utilized. Through optimization, a Cs2AgBiBr6-treated PSC achieves an open-circuit voltage of 1.12 V and an impressive PCE of 19.52%. Additionally, the Cs2AgBiBr6 passivation layer proves to be effective in bolstering the stability of PSCs. This work demonstrates an additional strategy and design motif to simultaneously increase the PCE of PSCs along with achieving improved stability.

Modelling grain refinement under additive manufacturing solidification conditions using high performance cellular automata

Despite increasing applications of additively manufactured parts, they still suffer from anisotropic mechanical properties and can experience cracking due to coarse columnar grain structures induced by metal 3D printing. Microstructural control is promising avenue to overcome these challenges, but requires deeper understanding of factors controlling solidification, particularly regarding grain refinement. Addressing this gap, this study explores grain refinement in Al-Cu alloys with a process-microstructure linking cellular automata-finite difference (CAFD) approach supported by single-track laser surface remelting (LSR) experiments. To enhance the understanding of nucleation behaviour in alloys under additive manufacturing solidification conditions, this research analyses the influence of nucleation parameters on the post-LSR microstructures. Additionally, this study explores the computational dimensions of microstructure modelling, testing CA mesh sensitivity effects and benchmarking our CAFD models on two high-performance computing platforms. The CAFD model captures well the key microstructural features observed in LSR Al-Cu alloys with and without grain refiner addition. It is shown that the maximum nucleation density has a significant effect on the final microstructure, resulting in different proportions of coarse columnar grains resulting from epitaxial solidification, newly nucleated thin columnar grains, and equiaxed grains.

Boosting acidic hydrogen peroxide electrosynthesis on 2D metal-organic framework nanosheets based on cobalt porphyrins

The 2-electron electrocatalytic oxygen reduction reaction (2e− ORR) to hydrogen peroxide (H2O2) represents a promising strategy to resolve the high energy consumption and increasing environmental concerns inherent in the traditional anthraquinone process. The acidic 2e− ORR has emerged as an exciting alternative for industrial-level H2O2 production, whereas is hampered by the inferior H2O2 selectivity due to the uncontrollable proton-coupled electron transfer processes in an acidic environment. Herein, an ultrathin 2D metal–organic frameworks (MOFs) nanosheet based on cobalt tetra(4-carboxyphenyl) porphine (Co-TCPP NSs) is designed to promote H2O2 selectivity up to 96.5 %, accompanied with a remarkable H2O2 generation rate of 4677.42 mg·L−1·h−1. Of note, the Co-TCPP NSs also demonstrate its potential for the electro-Fenton process with a cumulative H2O2 concentration of 1.21 wt%, highlighting its practical potential in portable H2O2 generation electrochemical devices for distributed applications. Our findings demonstrated that the efficient H2O2 electrosynthesis could be attributed to the attenuated *OOH adsorption over Co-N4 moiety on the Co-TCPP NSs, which consequently suppresses its further reduction to form H2O. This work highlights the potential of 2D MOF architecture for the 2e− ORR and provides an atomic-level insight into the enhanced H2O2 selectivity.

Recent Progress on Transition Metal Catalyzed Macrocyclizations Based on C-H Bond Activation at Heterocyclic Scaffolds.

Macrocycles are essential in protein-protein interactions and the preferential intake of bioactive scaffolds. Macrocycles are commonly synthesized by late-stage macrolactonizations, macrolactamizations, transition metal-catalyzed ring-closing metathesis, S-S bond-forming reactions, and copper-catalyzed alkyne-azide cycloaddition. Recently, transition metal-catalyzed C-H activation strategies have gained significant interest among chemists to synthesize macrocycles. This article provides a comprehensive overview of the transition metal-catalyzed macrocyclization via C-H bond functionalization of heterocycle-containing peptides, annulations, and heterocycle-ring construction through direct C-H bond functionalization. In the first part, palladium salt catalyzed coupling with indolyl C(sp3)-H and C(sp2)-H bonds for macrocyclization is reported. The second part summarizes rhodium-catalyzed macrocyclizations via site-selective C-H bond functionalization. Earth-abundant, less toxic 3d metal salt Mn-catalyzed cyclizations are reported in the latter part. This summary is expected to spark interest in emerging methods of macrocycle production among organic synthesis and chemical biology practitioners, helping to develop the discipline. We hope that this mini-review will also inspire synthetic chemists to explore new and broadly applicable C-C bond-forming strategies for macrocyclization via intramolecular C-H activation.

Mitigation of Gilbert Damping in the CoFe/CuOx Orbital Torque System.

Charge-spin interconversion processes underpin the generation of spin-orbit torques in magnetic/nonmagnetic bilayers. However, efficient sources of spin currents such as 5d metals are also efficient spin sinks, resulting in a large increase of magnetic damping. Here we show that a partially oxidized 3d metal can generate a strong orbital torque without a significant increase in damping. Measurements of the torque efficiency ξ and Gilbert damping α in CoFe/CuOx and CoFe/Pt indicate that ξ is comparable in the two systems. The increase in damping relative to a single CoFe layer is Δα < 0.002 in CoFe/CuOx and Δα ≈ 0.005-0.02 in CoFe/Pt, depending on CoFe thickness. We ascribe the nonreciprocal relationship between Δα and ξ in CoFe/CuOx to the small orbital-spin current ratio generated by magnetic resonance in CoFe and the lack of an efficient spin sink in CuOx. Our findings provide new perspectives on the efficient excitation of magnetization dynamics via the orbital torque.

(Invited) Diverse Strategies for Pseudocapacitance in 2D Materials and Beyond

As electronic technology advances, the need in safe and long-lasting energy storage devices that occupy minimum volume arises. Short charging times of several seconds to minutes, with energy densities comparable to those of batteries, can be achieved in pseudocapacitors. These are sub-class of supercapacitors, where capacitance is mediated by fast redox reactions and can enable at least an order of magnitude more energy to be stored than in typical electrical double layer capacitors. Transition metal oxides (e.g. RuO2, MnO2) and conducting polymers (e.g. polyaniline) serve as typical examples. However, these materials are often high in cost and/or suffer from low cycling stability. As a result, the search for new pseudocapacitive materials constitutes an important direction today.In my talk, I will discuss various strategies to improve the performance metrics of pseudocapacitors, specifically focusing on enhancing capacitance and charging rates. I will primarily discuss the electrochemical behavior of layered materials, such as 2D transition metal carbides (MXenes) and 2D pi-conjugated conductive metal-organic frameworks, with a strong emphasis on understanding the mechanisms of charge storage and the various factors influencing electrochemical performance. Additionally, I will explore the role of cation intercalation in layered MXenes as a means to finely tune their electrochemical responses.

Voltammetric Investigations of Low-Coordinate Manganese As an Electrocatalyst for Organic Coupling and Functionalization

Earth-abundant, first row, low coordinate transition metal complexes are considered promising candidates for the electrocatalysis of many organic reactions. The use of transition metal catalysts is no stranger to the field of synthetic organic chemistry; however, many of the existing catalysts require the use of rare and expensive metals such as platinum, palladium, ruthenium, and iridium. In this study, we seek to identify and understand the mechanism by which an Mn(I) complex may act as an electrocatalyst for simple organic coupling and C-H functionalization reactions, beginning with the radicalization of benzyl bromide and benzyl chloride as representative organic halide substrates. The careful design and evaluation of this manganese complex has the potential to offer an effective non-toxic 3d metal electrocatalyst, provided that common transition metal behaviors, such as disproportionation or carbon-metal bond formation, are avoided. Initial characterization of the complex by cyclic voltammetry (CV) demonstrates general reversibility of the catalyst, while additions of benzyl halide exhibit the execution of the electron transfer and catalytic step. Electrochemical simulations run in parallel with CV experiments provide supplementary guidance into the relationship between the substrate and catalyst. Additional studies conducted using bulk electrolysis, mass spectrometry, nuclear magnetic resonance, and density functional theory (DFT) calculation will help to further characterize the mechanism and supporting details. Elucidation of the catalytic mechanism will allow us to use this electrocatalyst in a series of synthetic organic conditions and aid in our advancement toward sustainable organometallic catalysis.

Pendant Proton‐Relays Systematically Tune the Rate and Selectivity of Electrocatalytic Ammonia Generation in a Fe‐Porphyrin Based Metal–Organic Framework

AbstractElectrocatalytic nitrite reduction (eNO2RR) is a promising alternative route to produce ammonia (NH3). Until now, several molecular catalysts have shown capability to homogeneously reduce nitrite to NH3, while taking advantage of added secondary‐sphere functionalities to direct catalytic performance. Yet, realizing such control over heterogeneous electrocatalytic surfaces remains a challenge. Herein, we demonstrate that heterogenization of a Fe‐porphyrin molecular catalyst within a 2D Metal–Organic Framework (MOF), allows efficient eNO2RR to NH3. On top of that, installation of pendant proton relaying moieties proximal to the catalytic site, resulted in significant improvement in catalytic activity and selectivity. Notably, systematic manipulation of NH3 faradaic efficiency (up to 90 %) and partial current (5‐fold increase) was achieved by varying the proton relay‐to‐catalyst molar ratio. Electrochemical and spectroscopic analysis show that the proton relays simultaneously aid in generating and stabilizing of reactive Fe‐bound NO intermediate. Thus, this concept offers new molecular tools to tune heterogeneous electrocatalytic systems.

Topology Selectivity of a Conformationally Flexible Precursor by Selenium Doping

Conformational arrangements within nanostructures play a crucial role in shaping the overall configuration and determining the properties, for example in covalent/metal organic framework (COF/MOF) synthesis. In on-surface synthesis, conformational diversity often leads to uncontrollable or disordered structures. Therefore, exploration on controlling and directing the conformational arrangements is significant in achieving desired nanoarchitectures. In this study, a conformationally flexible precursor 2,4,6-tris(3-bromophenyl)-1,3,5-triazine (mTBPT) was employed, and a random phase consisting of C3h and Cs conformers was first obtained after deposition of mTBPT on Cu(111) from room temperature (RT) to ~365 K as expected. By low coverage (0.01 ML) selenium (Se) doping, we achieved the selectivity of the C3h conformer greatly and improved the nanopore structural homogeneity. The ordered 2D metal organic nanostructure from mTBPT could be fulfilled by Se doping from RT to ~365 K, and the deposition sequence of mTBPT and Se did not make any difference. Through the combination of high-resolution scanning tunneling microscopy and non-contact atomic force microscopy, we explored the regulation of the conformationally flexible mTBPT on Cu(111) and achieved the high topology selectivity by low coverage Se doping. Density functional theory calculations revealed the energy regulation of organometallics before and after Se doping at atomic level. These results could enrich the on-surface synthesis toolbox of conformationally flexible precursors, for the design of complex nanoarchitectures, and for future development of engineered nanomaterials and nanodevices. Figure 1

Liquid Metal-Modified 3D Cu Foam for Dendrite-Free Sodium Plating.

Sodium metal is regarded as one of the most promising anode materials due to its high theoretical capacity (1166mAhg-1) and low redox potential (-2.714V vs standard hydrogen electrode). However, the practical application of sodium metal is hindered by the formation of dendrites during Na stripping and plating, which can degrade performance and cause potential safety hazards. To address this issue, previous work focuses on leveraging either 3D current collectors or liquid metal modification on current collectors. In this work, both strategies are simultaneously leveraged to design a 3D Cu foam with liquid metal modification (LM@Cu) for dendrite-free sodium plating. The 3D configuration of Cu effectively reduces local current density and evenly distributes electric fields, while the introduction of liquid metal enhances the sodiophilicity of Cu to lower the nucleation barrier for sodium, thereby promoting its uniform plating. As a result, symmetric cells of Na with LM@Cu maintain stable cycling for over 2800h. Additionally, full cells comprising Na-LM@Cu and Na3V2(PO4)3 sustain 97.5% of the capacity upon 1000 cycles, underscoring the great potentiality of liquid metal-mediated 3D current collectors in energy storage.

Single Crystal Ruddlesden-Popper and Dion-Jacobson Metal Halide Perovskites for Visible Light Photodetectors: Present Status and Future Perspectives.

2D metal halide perovskites (MHPs), mainly the studied Ruddlesden-Popper (RP) and Dion-Jacobson (DJ) phases, have gained enormous popularity as optoelectronic materials owing to their self-assembled multiple quantum well structures, tunable semiconducting properties, and improved structural stability compared to their bulk 3D counterparts. The performance of polycrystalline thin film devices is limited due to the formation of defects and trap states. However, as studied so far, single crystal-based devices can provide a better platform to improve device performance and investigate their fundamental properties more reliably. This Review provides the first comprehensive report on the emerging field of RP and DJ perovskite single crystals and their use in visible light photodetectors of varied device configurations. This Review structurally summarizes the 2D MHP single crystal growth methods and the parameters that control the crystal growth process. In addition, the characterization techniques used to investigate their crystal properties are discussed. The review further provides detailed insights into the working mechanisms as well as the operational performance of 2D MHP single crystal photodetector devices. In the end, to outline the present status and future directions, this Review provides a forward-looking perspective concerning the technical challenges and bottlenecks associated with the developing field of RP and DJ perovskite single crystals. Therefore, this timely review will provide a detailed overview of the fast-growing field of 2D MHP single crystal-based photodetectors as well as ignite new concepts for a wide range of applications including solar cells, photocatalysts, solar H2 production, neuromorphic bioelectronics, memory devices, etc.

KCl acts as a flux to assist the growth of sub-millimeter-scale metallic 2D non-layered molybdenum dioxide

AbstractTwo-dimensional (2D) metal oxides (2DMOs), such as MoO2, have made impressive strides in recent years, and their applicability in a number of fields such as electronic devices, optoelectronic devices and lasers has been demonstrated. However, 2DMOs present challenges in their synthesis using conventional methods due to their non-van der Waals nature. We report that KCl acts as a flux to prepare large-area 2DMOs with sub-millimeter scale. We systematically investigate the effects of temperature, homogeneous time and cooling rate on the products in the flux method, demonstrating that in this reaction a saturated homogenous solution is obtained upon the melting of the salt and precursor. Afterward, the cooling rate was adjusted to regulate the thickness of the target crystals, leading to the precipitation of 2D non-layered material from the supersaturated solution; by applying this method, the highly crystalline non-layered 2D MoO2 flakes with so far the largest lateral size of up to sub-millimeter scale (~ 464 μm) were yielded. Electrical studies have revealed that the 2D MoO2 features metallic properties, with an excellent sheet resistance as low as 99 Ω·square−1 at room temperature, and exhibits a property of charge density wave in the measurement of resistivity as a function of temperature. Graphical abstract TOC (Table of Content)

Versatile Method for Preparing Two-Dimensional Metal Dihalides.

Ever since the ground-breaking isolation of graphene, numerous two-dimensional (2D) materials have emerged with 2D metal dihalides gaining significant attention due to their intriguing electrical and magnetic properties. In this study, we introduce an innovative approach via anhydrous solvent-induced recrystallization of bulk powders to obtain crystals of metal dihalides (MX2, with M = Cu, Ni, Co and X = Br, Cl, I), which can be exfoliated to 2D flakes. We demonstrate the effectiveness of our method using CuBr2 as an example, which forms large layered crystals. We investigate the structural properties of both the bulk and 2D CuBr2 using X-ray diffraction, along with Raman scattering and optical spectroscopy, revealing its quasi-1D chain structure, which translates to distinct emission and scattering characteristics. Furthermore, microultraviolet photoemission spectroscopy and electronic transport reveal the electronic properties of CuBr2 flakes, including their valence band structure. We extend our methodology to other metal halides and assess the stability of the metal halide flakes in controlled environments. We show that optical contrast can be used to characterize the flake thicknesses for these materials. Our findings demonstrate the versatility and potential applications of the proposed methodology for preparing and studying 2D metal halide flakes.

Enhancing Oxygen Activation Ability by Composite Interface Construction over a 2D Co3O4-Based Monolithic Catalyst for Toluene Oxidation.

Developing robust metal-based monolithic catalysts with efficient oxygen activation capacity is crucial for thermal catalytic treatment of volatile organic compound (VOC) pollution. Two-dimensional (2D) metal oxides are alternative thermal catalysts, but their traditional loading strategies on carriers still face challenges in practical applications. Herein, we propose a novel in situ molten salt-loading strategy that synchronously enables the construction of 2D Co3O4 and its growth on Fe foam for the first time to yield a unique monolithic catalyst named Co3O4/Fe-S. Compared to the Co3O4 nanocube-loaded Fe foam, Co3O4/Fe-S exhibits a significantly improved catalytic performance with a temperature reduction of 44 °C at 90% toluene conversion. Aberration-corrected scanning transmission electron microscopy and theoretical calculation suggest that Co3O4/Fe-S possesses abundant 2D Co3O4/Fe3O4 composite interfaces, which promote the construction of active sites (oxygen vacancy and Co3+) to boost oxygen activation and toluene chemisorption, thereby accelerating the transformation of reaction intermediates through Langmuir-Hinshelwood (L-H) and Mars-van Krevelen (MvK) mechanisms. Moreover, the growth mechanism reveals that 2D Co3O4/Fe3O4 composite interfaces are generated in situ in molten salt, inducing the growth of 2D Co3O4 onto the surface lattice of 2D Fe3O4. This study provides new insights into enhancing oxygen activation and opens an unprecedented avenue in preparing efficient monolithic catalysts for VOC oxidation.

Amine-substituted heterocyclic thioamide Cu(I) and Ag(I) complexes as effective anticancer and antibacterial agents targeting the periplasm of E. coli bacteria

Metal complexes showing dual activity against cancer and bacterial infections are currently the focus of significant interest for their potential in treating life-threatening diseases. Aiming to investigate the impact of ligand substituents on these bioactivity properties of Group 11 d10 metal complexes, we herein present a series of mononuclear Cu(I) and Ag(I) complexes featuring the bis–NH2–substituted heterocyclic thioamide dap2SH (=4,6-diaminopyrimidine-2-thione), namely [AgCl(dap2SH)(PPh3)2] (1), [CuBr(dap2SH)(PPh3)2] (2), [CuBr(dap2SH)(xantphos)] (3), [Ag(dap2S)(xantphos)] (4), and [Cu(dap2S)(xantphos)] (5) (xantphos = 4,5-bis(diphenylphosphino)-9,9-dimethylxanthene). Complexes were characterized by means of different physicochemical methods (i.e., single crystal X-ray diffraction as well as FTIR, NMR, UV–Vis and fluorescence spectroscopy), and studied in-vitro for their antibacterial and anticancer activity against a variety of bacterial strains and cancer cell lines. Complexes 1–3 effectively inhibited both Gram (+) and Gram (−) bacterial growth, while cellular uptake studies for the most potent complex 1 against E. coli bacteria revealed the accumulation of Ag(I) ions in the periplasm of the bacteria. A high anti-proliferative effect was observed for 1 and 5 against A549, MCF7 and PC3 cancer cell lines, with 1 being capable of inducing apoptosis in A549 cells, as suggested by flow cytometry analysis. DNA interaction studies revealed the capacity of 1 to intercalate between base-pairs of CT DNA. All complexes had a moderate-to-high capacity to scavenge free radicals preventing oxidative stress. Molecular docking calculations, in combination with the experimentally obtained data, provided insights for potential mechanisms of the bioactivity of the complexes.