Transition Metal Nanoparticles Research Articles

An ultrasensitive electrochemical biosensor based on logic transcription circuit-activated DNAzyme amplifier for flap endonuclease 1 activity detection

The accurate detection of flap endonuclease 1 (FEN1) activity is crucial for early cancer diagnosis and therapy. Herein, we have established a “target-substrate double-enhanced” DNA electrochemical biosensor by integrating a cleavage-ligation logic transcription circuit-activated DNAzyme amplifier with the transition-metal carbides-gold nanoparticles (MXene-Au) composites for the accurate detection of FEN1 activity. The FEN1 can be translated into a stable transcription hairpin DNA (TH), incorporating the catalytic strand of the DNAzyme via the logic transcription circuit. Then, the TH hybridizes with the substrate strand of DNAzyme and the DNAzyme amplifier can be activated, thus producing a significant quantity of single-stranded DNA (sDNA) and achieving the efficient amplification of the FEN1. Finally, the sDNA loaded with electroactive substances is immobilized on the capture DNA-anchored MXene-Au modified electrode, significantly enhancing the electrochemical signal intensity for highly sensitive FEN1 activity detection. The excellent selectivity and sensitivity of the proposed electrochemical biosensor can facilitate the accurate detection of FEN1 activity in biological samples and aid in screening FEN1-releated drugs. Additionally, three-input concatenated logic gates (AND-AND, INHIBIT-AND, and AND-OR) are constructed for FEN1 activity detection. Particularly, the AND-AND gate achieves logic detection of FEN1 activity in complex samples. Consequently, this bidirectionally enhanced electrochemical biosensor offers a novel analytical method for FEN1 activity detection, showing substantial promise for early diagnosis and drug discovery of FEN1-related disease.

Carbonized cellulose microspheres loaded with Pd NPs as catalyst in p-nitrophenol reduction and Suzuki-Miyaura coupling reaction

Catalytic reduction of p-nitrophenol is usually carried out using transition metal nanoparticles such as gold, palladium, silver and copper, especially palladium nanoparticles, which are characterized by fast reaction rate, high turnover frequency, good selectivity and high yield. However, the aggregation and precipitation of the metals lead to the decomposition of the catalyst, which results in a significant reduction of the catalytic activity. Therefore, the preparation of homogeneous stabilized palladium nanoparticle catalysts has been widely studied. Stabilized palladium nanoparticles mainly use synthetic polymers. Cellulose microspheres, as a natural polymer material with low cost and porous fiber network structure, are excellent carriers for stabilizing metal nanoparticles. Cellulose microspheres impregnated with palladium metal nanoparticles were carbonized to have a larger specific surface area and highly dispersed palladium nanoparticles, which exhibited excellent catalytic activity in the catalytic reduction of 4-nitrophenol. In this aspect, cellulose carbon-based microspheres Pd nanoparticles (Pd@CCM) catalysts were designed and characterized by SEM, TEM, EDS, XRD, FTIR, XPS, TGA, BET and so on. Furthermore, the catalytic performance of Pd@CCM catalysts were investigated via 4-nitrophenol reduction, which showed high catalytic activity. This catalyst also exhibited excellent catalytic performance in Suzuki-Miyaura coupling reaction. Linking aromatic monomer and benzene through Suzuki-Miyaura coupling was presented as an effective route to obtain polymeric substrate with low-cost and simple synthesis method. In addition, cellulose carbon-based microspheres Pd nanoparticles catalyst showed desirable recyclability with maintaining its catalytic activity even after five recycles. This work is highly suggestive on the heterogeneous catalysts design and application.

Preparation of Ni, Co doped hollow carbon nanocage from core-shell structure ZIF-8@ZIF-67 for nitrobenzene monitoring

Herein, we employed a Ni, Co duplex metal-doped hollow carbon nanocage derived from the core-shell Zeolite imidazole framework-8 (Zn)@Zeolite imidazole framework-67 (Co) (ZIF-8@ZIF-67) for the sensitive electrochemical detection of nitrobenzene (NB). The precursor was created by coating ZIF-67 on the surface of ZIF-8 through the epitaxial growth method, followed by Ni doping. Subsequent pyrolysis resulted in the formation of a Ni, Co duplex metal-doped hollow carbon nanocage. Characterization of the nanocomposite confirmed the unique hollow and porous structure of NiCo/C, maintaining a dodecahedral morphology with a uniform distribution of carbon and transition metal nanoparticles. The NiCo/C-modified electrode exhibits a wide linear dynamic range (0.05–11.22 μM and 11.22–230.06 μM), a lower limit of detection (0.14 μM), superior stability and selectivity for the detection of NB. Moreover, it shows appropriate practicality toward detecting NB in natural water samples.

Review of: "this mechanism, catalytic nanoparticles of metal alloys or transition metals (such as nickel, iron and cobalt) are considered spherical or floating on the substrate surface"

Review of: "this mechanism, catalytic nanoparticles of metal alloys or transition metals (such as nickel, iron and cobalt) are considered spherical or floating on the substrate surface"

Organic pollutants photodegradation increment with use of TiO2 nanotubes decorated with transition metals after pulsed laser treatment

Among various titanium(IV) oxide (TiO2, titania) structures, 1D nanotubes (TiO2 NTs) produced during the two-electrode anodization process, are extensively utilized in sensors or supercapacitors as well as in photo(electro)catalytic water splitting. However, due to wide bandgap and fast electron-hole recombination additional modifications, mostly concerned on materials surface, are required. According to the recent research, TiO2 NTs photo(electro)catalytic characteristic were markedly improved by the combination of surface decoration with transition metal nanoparticles further treated with the laser beam. Nevertheless, until recently, the photocatalytic ability of laser-treated TiO2 NTs for recalcitrant chemicals degradation were hardly described. In this regard, our work focuses on obtaining long, about 7.3 μm TiO2 NTs (L-TiO2 NTs), together with their photoactivity and physicochemical characteristics, as well as their alterations following surface modification utilizing transition metals (tungsten, chromium and nickel) together with laser treatment. Obtained L-TiO2 NTs are characterized by over 13.5 times larger BET surface area in comparison to reference spaced TiO2 NTs with approximately 2 μm length (0.61 m2 g−1 and 0.05 m2 g−1, respectively). This allowed for increasing of the materials photocatalytic activity in both UV–vis and vis light. Additionally, phenol photodegradation reached up to 34% (0.21·10−2 min−1) for tungsten-modified titania after laser annealing at 20 mJ cm2 fluence. The reaction mechanism research revealed that reduction of organic pollutants concentration was primarily caused by superoxide radical anions •O2−. Furthermore, obtained modified L-TiO2 NTs showed remarkable durability without losing their initial activity over ten photocatalytic cycles.

Carbon Nanotube Composites with Bimetallic Transition Metal Selenides as Efficient Electrocatalysts for Oxygen Evolution Reaction

Hydrogen fuel is a clean and versatile energy carrier that can be used for various applications, including transportation, power generation, and industrial processes. Electrocatalytic water splitting could be the most beneficial and facile approach for producing hydrogen. In this work, transition metal selenide composites with carbon nanotubes (CNTs) have been investigated for electrocatalytic water splitting. The synthesis process involved the facile one-step hydrothermal growth of transition metal nanoparticles over the CNTs and acted as an efficient electrode toward electrochemical water splitting. Scanning electron microscopy and XRD patterns reveal that nanoparticles were firmly anchored on the CNTs, resulting in the formation of composites. The electrochemical measurements reveal that CNT composite with nickel–cobalt selenides (NiCo-Se/CNTs@NF) display remarkable oxygen evolution reaction (OER) activity in basic media, which is an important part of hydrogen production. It demonstrates the lowest overpotential (η10mAcm−2) of 0.560 V vs. RHE, a reduced Tafel slope of 163 mV/dec, and lower charge transfer impedance for the OER process. The multi-metallic selenide composite with CNTs demonstrating unique nanostructure and synergistic effects offers a promising platform for enhancing electrocatalytic OER performance and opens up new avenues for efficient energy conversion and storage applications.

Confined Co@NCNTs as highly efficient catalysts for activating peroxymonosulfate: free radical and non-radical co-catalytic mechanisms.

A series of transition metal (Co, Ni, Fe) nanoparticles were confined in N-doped carbon nanotubes (NCNTs) prepared (Co@NCNTs, Ni@NCNTs, and Fe@NCNTs) by the polymerization method. The structure and composition of catalysts were well characterized. The catalytic activity of catalysts for activating peroxymonosulfate (PMS) was conducted via acid orange 7 (AO7) degradation. Among the catalysts, Co@NCNTs performed the best catalytic activity. Additionally, Co@NCNTs performed good catalytic activity in pH values of 2.39-10.98. Cl- andSO42- played a promotingroles in AO7 degradation.NO3- presented a weak effect on the catalytic performance of Co@NCNTs, while HCO3- and CO32- significantly suppressed the catalytic performance of Co@NCNTs. Both non-radical (1O2 and electron transfer) and free-radical (·OH and SO4·-) pathways were detected in the Co@NCNTs/PMS system. Notably, 1O2 was identified to be the main active specie in this study. The catalytic activity of Co@NCNTs gradually decreased after cycle reuse of Co@NCNTs. Finally, the toxicity of the AO7 degradation solution in the study was evaluated by Chlorella pyrenoidosa.

Advances in the Application of Transition-Metal Composite Nanozymes in the Field of Biomedicine.

Due to the limitation that natural peroxidase enzymes can only function in relatively mild environments, nanozymes have expanded the application of enzymology in the biological field by dint of their ability to maintain catalytic oxidative activity in relatively harsh environments. At the same time, the development of new and highly efficient composite nanozymes has been a challenge due to the limitations of monometallic particles in applications and the inherently poor enzyme-mimetic activity of composite nanozymes. The inherent enzyme-mimicking activity is due to Au, Ag, and Pt, along with other transition metals. Moreover, the nanomaterials exhibit excellent enzyme-mimicking activity when composited with other materials. Therefore, this paper focuses on composite nanozymes with simulated peroxidase activity that have been prepared using noble metals such as Au, Ag, and Pt and other transition metal nanoparticles in recent years. Their simulated enzymatic activity is utilized for biomedical applications such as glucose detection, cancer cell detection and tumor treatment, and antibacterial applications.

Surface effects in ferrimagnetic TbFe rare-earth–transition-metal thin films and nanoparticles

Surface effects in ferrimagnetic TbFe rare-earth–transition-metal thin films and nanoparticles

Synthesis of core@shell catalysts guided by Tammann temperature

Designing high-performance thermal catalysts with stable catalytic sites is an important challenge. Conventional wisdom holds that strong metal-support interactions can benefit the catalyst performance, but there is a knowledge gap in generalizing this effect across different metals. Here, we have successfully developed a generalizable strong metal-support interaction strategy guided by Tammann temperatures of materials, enabling functional oxide encapsulation of transition metal nanocatalysts. As an illustrative example, Co@BaAl2O4 core@shell is synthesized and tracked in real-time through in-situ microscopy and spectroscopy, revealing an unconventional strong metal-support interaction encapsulation mechanism. Notably, Co@BaAl2O4 exhibits exceptional activity relative to previously reported core@shell catalysts, displaying excellent long-term stability during high-temperature chemical reactions and overcoming the durability and reusability limitations of conventional supported catalysts. This pioneering design and widely applicable approach has been validated to guide the encapsulation of various transition metal nanoparticles for environmental tolerance functionalities, offering great potential to advance energy, catalysis, and environmental fields.

Tip Growth of Quasi-Metallic Bilayer Graphene Nanoribbons with Armchair Chirality.

Graphene nanoribbons (GNRs), quasi one-dimensional (1D) narrow strips of graphene, have shown promise for high-performance nanoelectronics due to their exceptionally high carrier mobility and structurally tunable bandgaps. However, producing chirality-uniform GNRs on insulating substrates remains a big challenge. Here, we report the successful growth of bilayer GNRs with predominantly armchair chirality and ultranarrow widths (<5 nm) on insulating hexagonal boron nitride (h-BN) substrates using chemical vapor deposition (CVD). The growth of GNRs is catalyzed by transition metal nanoparticles, including Fe, Co, and Ni, through a unique tip-growth mechanism. Notably, GNRs catalyzed by Ni exhibit a high purity (97.3%) of armchair chirality. Electron transport measurements indicate that the ultrathin bilayer armchair GNRs exhibit quasi-metallic behavior. This quasi-metallicity is further supported by density functional theory (DFT) calculations, which reveal a significantly reduced bandgap in bilayer armchair GNRs. The chirality-specific GNRs reported here offer promising advancements for the application of graphene in nanoelectronics.

Enhanced room-temperature hydrogen storage by CuNi nanoparticles decorated in metal-organic framework UiO-66(Zr)

This study demonstrates the significant effect of incorporating inexpensive transition metal nanoparticles into metal-organic frameworks (MOFs) to improve their room-temperature hydrogen storage properties. Low-cost nanoparticles (Cu, Ni, and CuNi) were incorporated into UiO-66(Zr) via the double-solvent approach (DSA) plus chemical reduction processes. All composites exhibited higher hydrogen storage capacity compared to pure UiO-66 at both room temperature and 60 bar. Notably, the hydrogen spillover efficiency of CuNi nanoparticles loaded in UiO-66 was comparable to that of MOF adsorbents embedded with noble metals such as Pd and Pt. The hydrogen storage capacity of CuNi@UiO-66 was significantly increased from 0.20 wt% to 0.74 wt%. DFT calculations showed that the CuNi alloys facilitated the adsorption and dissociation of hydrogen molecules in comparison to the single metal nanoparticles, thus favoring the hydrogen spillover effect and improving the hydrogen storage performance. This work demonstrates the potential of designing MOF loaded with inexpensive metal nanoparticles for optimized room-temperature hydrogen storage.

Superposition continuum mechanics (hydrodynamics) for systems with spin polarization defined evolution

The class of physical systems with collectivized electrons, in which the influence of spin polarization on the character of evolution crucially matters, is closely scrutinized. The hydrodynamic theory for its description is developed and the grounds of its methodological part are evaluated. The binary factorized representation of the density function serves as a master hypothesis. The system of motion equations has been deduced by means of the stationary action principle. The exponential scaling of its size in relation to the number of spin carriers is identified. We show its fundamental computability in spectral domain of the factorized discrete Fourier transform. The adequacy of description of the physics of electron gas–light interaction with its use has been assessed by the example of localized plasmon excitation in transition metal nanoparticles. It has been demonstrated the equivalence of the proposed model to many body quantum mechanics for the Shrödinger equation (SE) with operator 4–potential. The linearity of superposition mechanics is discussed in parallel. The methodological part of the approach has allowed factoring the many body SE and for the sake of validation has been translated to the approximately solved classically computable model. The results obtained with its use allow interpreting the viscous (drudean) damping in spherical particles as a consequence of maximal decoherence in motion of spin configurations.

(Invited) Development of Sustainable Electrocatalysts for Anion Exchange Membrane Fuel Cells and Electrolyzers

The electrocatalytic hydrogen oxidation (HOR) and evolution (HER) reactions under alkaline conditions are kinetically slow processes even when Pt group metals are employed. This presentation discusses our strategies to improve the activity of non platinum catalysts. For example, to improve the alkaline HOR activity of transition metal nanoparticles we look at engineering strong interactions with metal oxides incorporated with carbon-based catalyst supports.(1,2) Another strategy involves utilizing novel carbon materials such as onion like carbon (OLC). We have shown that the combination of CeO2 and OLC in Pd–CeO2/OLC induces surface defects and modifies the electronic structure of the Pd-OLC interface, significantly improving electrical conductivity due to enhanced charge redistribution. Such results were corroborated by density functional theory (DFT) calculations.(3) Using this strategy, peak power densities of up to 2 W cm-2 have been achieved when Pd-CeO2 is incorporated in AEMFCs.(4) Regarding the alkaline HER, mixed phase Ni-Mo and MoO3-x materials are known to have enhanced alkaline hydrogen evolution reaction (HER) activity. Here we describe the optimization of the preparation of an active HER catalyst composed of MoO2 surface nanorod arrays on nickel foam (see Figure). Large circular cathode electrodes (Area 80 cm2) were prepared and tested in a three cell stack AEM electrolyser.(5) M. V. Pagliaro, C. L. Wen, B. Sa, B. Y. Liu, M. Bellini, F. Bartoli, S. Sahoo, R. K. Singh, S. P. Alpay, H. A. Miller and D. R. Dekel, ACS Catal., 10894 (2022).M. V. Pagliaro, M. Bellini, F. Bartoli, J. Filippi, A. Marchionni, C. Castello, W. Oberhauser, L. Poggini, B. Cortigiani, L. Capozzoli, A. Lavacchi, H. A. Miller and F. Vizza, Inorg. Chim. Acta, 543 (2022).J. Ogada, A. K. Ipadeola, P. V. Mwonga, A. B. Haruna, F. Nichols, S. W. Chen, H. A. Miller, M. V. Pagliaro, F. Vizza, J. R. Varcoe, D. M. Meira, D. M. Wamwangi and K. I. Ozoemena, ACS Catal., 12, 10938 (2022).H. A. Miller, M. Bellini, D. R. Dekel, and F. Vizza, Electrochemistry Communications, 135, 107219 (2022).F. Bartoli, L. Capozzoli, T. Peruzzolo, M. Marelli, C. Evangelisti, k. Bouzek, J. Hnat, G. Serrano, L. Poggini, K. Stojanovski, V. Briega-Martos, S. Cherevko, H. A. Miller and F. Vizza, J. Mater. Chem. A, 11, 5789 (2023). Figure 1

Selective photothermal reduction of CO2 to CH4 via the synergistic effect of Ni-nanoparticle@NiO-nanosheet/V2C-MXene catalyst

Photothermal catalytic carbon dioxide (CO2) reduction has attracted increasing research attention as a promising method for recycling CO2 and producing renewable energy. However, it remains a challenge in the improvement of catalytic activity with regulated product selectivity in view of practical applications. Herein, we develop the two-dimensional layered V2C MXene (VC) supported Ni nanoparticle and NiO nanosheet (Ni@NiO/VC) composite as an efficient catalyst for selective photothermal reduction of CO2 to CH4. The optimal 0.8Ni@NiO/VC catalyst exhibits 48.1 % CO2 conversion with an evolution rate of 33.2 mmol/gcat/h and 99.2 % selectivity for CH4 production under a 300 W full-arc xenon lamp irradiation. Moreover, a long-term cyclic photothermal CO2 reduction reaction demonstrates the excellent stability of 0.8Ni@NiO/VC. The enhanced photothermal CO2 reduction activity with a high CH4 selectivity could be attributed to the large specific surface area and excellent photothermal effect of V2C MXene, and the synergistic effect of Ni and NiO on adsorption/activation of H2 and CO2 molecules. This work provides a feasible strategy for the construction of efficient photothermal CO2 reduction catalyst by properly incorporating transition metal nanoparticles and metal oxide with a suitable MXene.

Tailoring Microwave Absorption Performance Using Tunable Core–Shell CoNi Alloy Nanospheres

In contemporary research endeavors, we have successfully synthesized a composite material endowed with extraordinary microwave absorption properties through a meticulously designed process involving the encapsulation of transition metal nanoparticles with a phenolic resin layer. This innovative material, centered around a core–shell architecture, boasts the incorporation of transition metals Co and Ni, presenting a systematic exploration of their compositional influence on the material’s wave absorption characteristics. Our investigation unravels a sophisticated interplay between alloy composition and microwave absorption performance. Noteworthy observations reveal a non-linear correlation between nickel content and absorption efficiency, where an initial decline precedes a subsequent augmentation. Intriguingly, this dynamic behavior is accompanied by a gradual shift in the absorption peak towards lower frequencies, elucidating the tunable nature of the material’s performance. Crucially, the pinnacle of absorption efficiency is attained at a precisely tuned Co:Ni ratio of 2:1, underscoring the significance of alloy composition in tailoring the material’s electromagnetic response. At an absorber thickness of 2.1 mm, our engineered material achieves a remarkable minimum reflection loss (RL) of −46.1 dB at a frequency of 13.5 GHz. This achievement is coupled with an impressive effective absorption bandwidth spanning 5.5 GHz, indicative of the material’s versatility and applicability across a wide frequency range. The results not only highlight the efficacy of the core–shell CoNi alloy composites but also emphasize the importance of meticulous composition control in achieving optimal microwave absorption performance. The work reported here presents a notable advancement in the synthesis of tunable microwave-absorbing materials, showcasing the potential for tailored electromagnetic responses. The intricate relationship between alloy composition and absorption characteristics elucidated in this study opens avenues for the development of radar-absorbing materials that meet the evolving demands of reduced thickness, light weight, and enhanced absorption performance across diverse frequency ranges.

Nano-enzyme colorimetric biosensor and its application

Nano-enzymatic colorimetric biosensors have emerged as a promising technology for identifying and measuring analytes. These biosensors utilize nano-enzymes, which are nanomaterials with enzyme-like properties, to catalyze reactions that cause color changes. The simplicity, cost-effectiveness, and ability to visually interpret results without complex instrumentation make this colorimetric sensing technique advantageous. The interaction between the analyte and nanomaterial is crucial in the mechanism of these biosensors, where binding of the analyte to the nano-enzyme's surface triggers a catalytic process resulting in a noticeable color change. Gold nanoparticles (Au NPs) and transition metal nanoparticles are explored for their unique characteristics and potential applications in colorimetric biosensors. Graphene, a carbon substance, is also discussed for its potential in biosensing applications. The use of nano-enzyme colorimetric biosensors in medical diagnosis, environmental protection, and antibacterial applications is expanding rapidly. The article highlights the development of biosensors for identifying oxidase enzyme substrates in food and biological samples, utilizing immobilized enzymes on magnetic nanoparticles and the CUPRAC colorimetric method for detection. The potential of nano-enzyme colorimetric biosensors in medical diagnosis is emphasized, offering a quick, accurate, and practical method for identifying biomolecules and disorders, with the potential for improving patient outcomes and advancing healthcare through further research and development.

Polyethylenimine as a Versatile Simultaneous Reducing and Stabilizing Agent Enabling One-Pot Synthesis of Transition-Metal Nanoparticles: Fundamental Aspects and Practical Implications.

The large surface area of metallic nanoparticles provides them with particular optical, chemical, and biological properties, accordingly enabling their use in a wide array of applications. In this regard, facile and fast synthetic approaches are desirable for ready-to-use functional materials. Following early investigations focused on the direct synthesis of polymer-coated gold nanoparticles, we herein demonstrate that such a strategy can be used to manufacture different types of d-block transition-metal nanoparticles via a one-pot method in aqueous media and mild temperature conditions. Gold (Au3+), palladium (Pd2+), and silver (Ag+) ions could be reduced using only polyethylenimine (PEI) or PEI derivatives acting simultaneously as a reducing and stabilizing agent and without the aid of any other external agent. The process gave rise, for instance, to Pd urchin-like nanostructures with a large surface area which confers to them outstanding catalytic performance compared to AuNPs and AgNPs produced using the same strategy. The polymer-stabilized AgNPs were demonstrated to be biocide against a variety of microorganisms, although AuNPs and PdNPs do not hold such an attribute at least in the probed concentration range. These findings may provide significant advances toward the practical, facile, and ready-to-use manufacturing of transition-metal nanoparticles for a myriad of applications.

TRANSITION METAL NANOPARTICLES AS PROMISING ANTIMICROBIAL AGENTS

The bacterial spread can pose a significant risk in the transmission of infectious diseases. Nanomaterials, including synthetic antibacterial nanoparticles, have emerged as a promising solution to combat bacterial infections due to their unique physicochemical properties. Metal nanoparticles have been shown to exhibit potent antimicrobial activity against a broad spectrum of bacteria, including both gram-positive and gram-negative strains. One of the main advantages of using metal nanoparticles as antibacterial agents is their ability to penetrate the bacterial cell wall and disrupt cellular processes. This disruption can lead to the inhibition of bacterial growth and ultimately, bacterial death. Furthermore, metal nanoparticles can be engineered with specific surface modifications that enhance their antibacterial activity and improve their biocompatibility. These modifications can include the attachment of targeting ligands, peptides, or antibodies to the nanoparticle surface, which can increase their specificity toward bacterial cells and reduce their toxicity toward mammalian cells. Overall, the use of metal nanoparticles as antibacterial agents holds great promise for the development of novel therapeutic strategies to combat bacterial infections, both in vitro and in vivo. In this paper, we highlight the development of metal NPs, particularly those based on Mn, Fe, Co, Zn and Cu for their antimicrobial properties and related mechanisms.

Evaluation of binding compatibility among transition metal nanoparticles towards graphene quantum dots and their magnetic properties

Evaluation of binding compatibility among transition metal nanoparticles towards graphene quantum dots and their magnetic properties