Bimetallic Nanoparticles Research Articles

A highly efficient and stable PtNi bimetallic nanoparticles modified on Mo2C decorated N-doped carbon flowers catalysts for the remediation of environmental pollutants

The unregulated discharge of nitroaromatics (NAs) and organic dye contaminants into aquatic ecosystems is a growing global concern, highlighting the urgent need for the development of effective wastewater treatment technology. In this study, we prepared Mo2C decorated on N- doped carbon flowers supported with PtNi bimetallic (PtxNiy@Mo2C/NCF) nanoparticles using the self-polymerization of dopamine and followed by the chemical reduction methods. These catalysts, with varying Pt:Ni ratios, were designed for the highly efficient catalytic reduction of NAs and rhodamine b (RhB) under the mild reaction conditions. The HR-TEM images confirmed the formation of spherical PtNi bimetallic NPs with an average diameter of 1.68 ± 0.6 nm. The prepared PtxNiy@Mo2C/NCF catalysts exhibited significantly higher catalytic efficiency for 4-nitrophenol (4-NP) reduction compared to their respective monometallic counterparts using NaBH4. Particularly, the Pt0.75Ni0.25@Mo2C/NCF catalyst showed superior catalytic activity with the apparent rate constant (kapp: 0.6703 min−1) and TOF (17.0 × 10−7 mol mg−1 min−1) and high recyclability over eight consecutive recycles. Furthermore, the Pt0.75Ni0.25@Mo2C/NCF catalyst also exhibited high catalytic activity for other NAs and RhB dye reduction with excellent yields. This enhanced catalytic activity of Pt0.75Ni0.25@Mo2C/NCF catalyst could be ascribed to the synergistic effect of the bimetallic systems, leading to more efficient reactions. Additional experiments were conducted on a fixed bed reactor to demonstrate that the Pt0.75Ni0.25@Mo2C/NCF catalyst effectively reduce both 4-NP and RhB dye over 15 successive runs. This work may pave the way for using PtxNiy@Mo2C/NCF catalysts in various wastewater treatment applications.

A colorimetric pocket sensor for rapid detection of chemical injuries caused by sulfur mustard in the war veterans using plasma composition analysis

A pocket sensor was provided by immobilizing twelve color mixtures containing organic dyes and copper-silver bimetallic nanoparticles coated with dopamine (Dopamine/Ag@Cu BMNPs) on a paper substrate. Due to the catalytic properties of the BMNPs, the index metabolites of the plasma were converted into aldehyde or acid compounds that interacted with the organic dyes. The assay was presented to monitor the changes in the plasma sample’s metabolites of 123 injured veteran and 40 healthy people. It is possible to observe the response of sensor with the naked eye within 3 min. To perform this discrimination, the proposed sensor was found to be 87% accurate. The quantitative responses of the sensor were indicated a strong correlation with the severity of the injury. The low cost of the fabrication process, availability, and non-invasiveness of the prepared assay make it an acceptable diagnostic method in hospitals and medical centers.

Selective and Comparative Study of B/nZVCu-Fe and B/nZVCu-Zn Nanoparticles as Fluorescent Probe for Dopamine in Presence of its Interference Molecules.

This work focuses on the synthesis of Bentonite supported nano zero valent bimetallic nanoparticles (B/nZVCu-M NPs) to be utilized for fast and highly sensitive, reversible, fluorescent determination of dopamine (DA) in the presence of dopamine, other biomolecules and ions. The X-ray Photoelectron Spectroscopy(XPS), Powder X-Ray Diffraction(PXRD) and Scanning Electron Microscopy(SEM) revealed the formation of nanoparticles with size ranging from 15 to 20nm. The composition was revealed by Fourier Transform Infrared(FTIR) Spectoscopy and Energy Dispersive X-Ray (EDX) Analysis. The Limits of Detection(LOD) were noted to be 5.57nM and 6.07nM. The binding of DA is noted to be reversible with respect to EDTA2-. Furthermore, the developed sensor exhibited good repeatability, satisfactory long-term stability, and was successfully used for the selective detection of dopamine sample with desired recoveries or reversibilities. The main aim of our work is to selectively detect dopamine in presence of its major interferents and biomolecules that are normally present/ co-exist with dopamine in biological systems.

Robust Ag-Co bimetallic nanoparticles: Dual role in catalytic and triboelectric performance

Bimetallic nanoparticles are of great significance in numerous areas due to their unique properties and diverse applications. In the present study, silver (Ag) and cobalt (Co) monometallic nanoparticles (MNPs) and AgCo bimetallic nanoparticles (BNPs), are synthesized using a simple wet chemical route. Various analytical techniques are adopted for the confirmation of the BNPs. Powder X-ray diffraction (PXRD) analysis revealed the formation of FCC-structure. Transmission Electron Microscopy (TEM) micrographs confirmed the bimetallic nature and Janus structure. The synthesized nanoparticles exhibit higher catalytic activity for degrading 4-nitrophenol dye. Recognizing the potential of metal nanoparticles to significantly boost the efficiency of triboelectric nanogenerators (TENG), the synthesized AgCo bimetallic nanoparticles are incorporated into polymer matrix to meticulously analyze the impact on the triboelectric performance. Interestingly, TENG with a higher composite quantity of 8 ml BNPs exhibited greater performance, generating an output voltage of about 270.52 V and a current of 5.24 µA. Hence, the procured synergistic BNPs show their promising avenue towards both water treatment and energy harvesting applications.

Plant-mediated bimetallic nanoparticles synthesis for catalytic degradation of malachite green

Plant-mediated bimetallic nanoparticles synthesis for catalytic degradation of malachite green

Anticancer, antimicrobial and antioxidant activity of CuO–ZnO bimetallic nanoparticles: green synthesised from Eryngium foetidum leaf extract

In the present study, green synthetic pathway was adapted to synthesize CuO–ZnO bimetallic nanoparticles (BNPs) using Eryngium foetidum leaf extract and their anti-cancer activity against MCF7 breast cancer cell lines, anti-microbial activity and in vitro anti-oxidant activity were evaluated. Various bio-active compounds present in leaf extract were responsible for the reduction of CuO–ZnO NPs from respective Cu2+ and Zn2+ metal precursors. In the present study, the involvement of bio-active compounds present in E. foetidum extract before and after green synthesis of BNPs were evaluated for the first time. Rod-shaped and spherical structural morphology of synthesized BNPs were revealed by using FESEM, TEM, and XRD analysis with particle size ranged from 7 to 23 nm with an average size of 16.49 nm. The distribution of Cu and Zn were confirmed by elemental mapping. The green synthesized CuO–ZnO NPs showed significant cytotoxic effect with the inhibition rate 89.20 ± 0.03% at concentration of 500 μg/mL. Again, good antioxidant activity with IC50; 0.253 mg/mL and antimicrobial activity of BNPs were also evaluated with the increasing order of MIC; E. coli (7.81 μg/mL) < B. subtilis (62.5 μg/mL) < S. aureus (31.25 μg/mL).

Complete dehalogenation of chloramphenicol by bimetallic alloy Pd-Au nanoparticles in a H2-Based membrane Catalyst-Film reactor

An effective treatment method to achieve complete dehalogenation of halogenated antibiotics is an urgent affair, because partially dehalogenated products remain persistent pollutants and sometimes having higher toxicity than the original antibiotics. This study is the first to achieve complete reductive dechlorination of chloramphenicol (CAP) using bimetallic alloy Pd-Au nanoparticles (Pd-AuNPs) in a hydrogen (H2)-based membrane catalyst-film reactor (H2-MCfR). Compared to mono-Pd nanoparticles (PdNPs), bimetallic alloy Pd-AuNPs gave faster removal and more complete dechlorination of CAP in batch and continuous-flow experiments. Notably, complete CAP dechlorination was achieved with a catalyst film of Pd-AuNPs (mole ratio 1:1) that had negligible catalyst loss in a 20-day continuous operation. LC-MS identified the products of reductive dechlorination, and the dominant pathways differed significantly between PdNPs and Pd-AuNPs. In particular, Pd-AuNPs favored reductive dechlorination, while PdNPs favored reduction of the –NO2 group, which led to partially dechlorinated products that were stable. Density functional theory (DFT) calculations showed how the Au atoms reduced the adsorption energy of reactants, which affected reaction selectivity. Toxicity prediction model confirmed that reducing dechlorination significantly decreased acute toxicity to fish, daphnia and green algae. Thus, the MCfR with Pd-AuNP catalysts offers promise for achieving complete dechlorination of CAP and inspires further studies for other halogenated antibiotics.

Co-Deposition of Bimetallic Au-Pt with L-Cysteine on Electrodes and Removal of Copper by Iron Powder for Trace Aqueous Arsenic Detection

Much progress has been made in the determination of As (III), while numerous electrochemical sensors based on metal nanomaterials with significant sensitivity and precision have been developed. However, further research is still required to achieve rapid detection and avoid interference from other metal ions (especially copper ions). In this study, bimetallic AuPt nanoparticles are electrochemically modified with screen printing electrodes. What’s more, L-cysteine also self-assembles with AuNPs through Au-S bond to enhance the electrochemical performance. To overcome the interference of Cu (II) in the sensing process, the reduced iron powder was chosen to remove Cu (II) and other oxidizing organics in aqueous solutions. The lowest detectable amount is 0.139 ppb, a linear range of 1~50 ppb with superlative stability by differential pulse anodic stripping voltammetry. Fortunately, the reduced iron powder could eliminate the Cu (II) with no effect on the As (III) signal.

Silver-based bimetallic nanozyme fabrics with peroxidase-mimic activity for urinary glucose detection

The enhanced catalytic properties of bimetallic nanoparticles have been extensively investigated. In this study, bimetallic Ag-M (M = Au, Pt, or Pd) cotton fabrics were fabricated using a combination of electroless deposition and galvanic replacement reactions, and improvement in their peroxidase-mimicking catalytic activity compared to that of the parent Ag fabric was studied. The Ag-Pt bimetallic nanozyme fabric, which showed the highest catalytic activity and ability to simultaneously generate hydroxyl (•OH) and superoxide (O2•−) radicals, was assessed as a urine glucose sensor. This nanozyme fabric sensor could directly detect urinary glucose in the pathophysiologically relevant high millimolar range without requiring sample predilution. The sensor could achieve performance on par with that of the current clinical gold standard assay. These features of the Ag-Pt nanozyme sensor, particularly its ability to avoid interference effects from complex urinary matrices, position it as a viable candidate for point-of-care urinary glucose monitoring.Graphical

Anti-Inflammatory and Antioxidant Potential of Green Synthesized Iron Zinc Oxide (Fe0.25-ZnO) Nanoparticles of the Elaeagnus angustifolia.

Research interest in examining Elaeagnus angustifolia's potential as a source of anti-inflammatory and antioxidant agents has grown as a result of the plant's endorsement as a rich source of bioactive chemicals with promising anti-inflammatory and antioxidant activity. In this study, zinc oxide (Fe0.25-ZnO) bimetallic nanoparticles (E.ang-Fe0.25-ZnO NPs) were synthesized using an aqueous extract of Elaeagnus angustifolia. Synthesized Fe0.25-ZnO nanoparticles were characterized by FTIR and XRD. The anti-inflammatory and antioxidant activities were investigated in LPS-stimulated RAW 264.7 macrophages using RT-PCR and ELISA techniques for antioxidant- and inflammation-related genes. The concentration of 39.6 μg/ml of E.ang-Fe0.25-ZnO NPs demonstrated a significant anti-inflammatory activity by suppressing the mRNA levels of TNF-α and IL-6 by 88.3 %±1.9 and 93.6 %±0.1, respectively, compared to LPS-stimulated cells. This was confirmed by the significant reduction of TNF-α and IL-6 secretion levels from 95.2 and 495.6 pg/ml in LPS-stimulated cells to 5.6 and 26.5 pg/ml in E.ang-Fe0.25-ZnO treated group. In addition, E.ang-Fe0.25-ZnO NPs nanoparticles treatment significantly enhanced the expression of antioxidant-related genes, SOD and CAT. Together, our results proved that phyto-mediated Fe0.25-ZnO nanoparticles using Elaeagnus angustifolia have great potential in biomedical applications such as anti-inflammatory and antioxidant.

Hydrogen evolution from NaBH4 using novel Ni/Pt nanoparticles decorated on a niobium-based composite

The niobium-based nanocomposite (Nb-CP), inspired by MOF-based synthesis, was developed utilizing the ligands 4-benzenedicarboxylic acid (BDC) and 1,3,5-benzenetricarboxylic acid (BTC). This material was decorated with bimetallic nanoparticles (Ni2/Pt8 NPs-Nb-CP) and applied for the first time for hydrogen evolution from sodium borohydride (NaBH4). Characterization results indicated successful synthesis. The FT-IR analysis revealed the presence of functional groups such as -C-H, –CO, and -O-H from ligands in the composite. Thermogravimetric analysis confirmed the thermal stability of the niobium composite (Nb-CP). Through X-ray diffraction (XRD), peaks associated with sodium niobate were detected. Additionally, the material was functionalized with bimetallic Ni/Pt nanoparticles, whose presence was also identified by XRD. The cubic morphology of the material was observed, with the decoration of bimetallic nanoparticles (Ni2/Pt8 NPs-Nb-CP) with an average size of 7.80 ± 0.10 nm, uniformly distributed in Nb-CP. The catalytic performance of the material was evaluated in hydrogen evolution from NaBH4. Various reaction parameters were investigated, such as nanoparticle composition, variation in NaBH4 concentration, catalyst dose, NaOH concentration, and temperature. Remarkably, the material exhibited a hydrogen generation rate (HGR) of 1782 mL min−1 g−1cat and an activation energy of 23.1 kJ mol−1. Furthermore, it demonstrated efficiency close to 100% over 16 consecutive reaction cycles, indicating its promising stability and reusability. This study highlights the potential of Ni2/Pt8 NPs-Nb-CP as an efficient and durable catalyst for hydrogen production through borohydride hydrolysis, providing insights into the design and application of advanced heterogeneous catalytic materials.

N-doped-graphene-supported Ni/Co bimetallic catalysts for zinc-air batteries

Electrocatalysis is essential for enhancing the energy conversion efficiency of zinc–air batteries. Nonetheless, the high cost and insufficient stability of electrocatalysts continue to hinder their commercial application. This study introduces a bifunctional composite electrocatalyst, NiCo–NG, consisting of Ni/Co bimetallic nanoparticles. The in situ integration of nanoscale graphene mitigates the agglomeration of Ni/Co metal atoms, resulting in a porous structure with a high specific surface area up to 244.6 m2 g−1. Notably, the NiCo–NG catalyst demonstrates enhanced conductivity, achieving an oxygen reduction reaction (ORR) half-wave potential of 0.793 V and a limiting current density of 7.64 mA cm−2. This catalyst exhibits superior performance to commercial Pt/C electrodes, which exhibit a half-wave potential of 0.836 V and a limiting current density of 0.6 mA cm−2. Moreover, the overpotential for the oxygen evolution reaction (OER) at a current density of 10 mA cm−2 is only 306.3 mV. The introduction of Ni significantly augments the catalytic activity. Employing this dual-functional catalyst in rechargeable zinc–air batteries yields a maximum power density of 181.9 mW cm−2 and a specific capacity of 804.2 mAh·gZn−1. In addition, the fabricated battery demonstrates remarkable stability, enduring up to 3000 charge–discharge cycles. Ultimately, this research offers a novel electrocatalyst that could advance the commercialization of zinc–air batteries.

Glassy carbon electrodes modified with graphitic carbon nitride nanosheets and CoNiO2 bimetallic oxide nanoparticles as electrochemical sensor for Sunitinib detection in human fluid matrices and pharmaceutical samples.

Asophisticated electrochemical sensoris presented employing a glassy carbon electrode (GCE) modified with a novel composite of synthesized graphitic carbon nitride (g-C3N4) and CoNiO2 bimetallic oxide nanoparticles (g-C3N4/CoNiO2). The sensor's electrocatalytic capabilities for Sunitinib (SUNI) oxidation were demonstratedexceptional performance with a calculated detection limit (LOD) of 52.0nM. The successful synthesis and integrity of the composite were confirmed through meticulous characterization using various techniques. FT-IR analysis affirmed the successful synthesis of g-C3N4/CoNiO2 by providing insights into its molecular structure. XRD, FE-SEM, SEM-EDX, and BET analyses collectively validated the material's structural integrity, surface morphology, and electrocatalytic performance. Optimization of key analytical parameters, such as loading volume, concentration, electrolyte solution type, and pH, enhanced the electrocatalytic sensing capabilities of g-C3N4/CoNiO2. The synergistic interaction between g-C3N4 and CoNiO2 bimetallic oxide nanoparticles executed the sensor highly effective in the electrical oxidation of SUNI. Across a concentration range of 0.1-83.8µMSUNI, the anodic peak current exhibited a linear increasewith good precision. Application of the newly developed g-C3N4/CoNiO2 system to detect SUNI in a variety of samples, including urine, human serum, and capsule dosage forms, obtained satisfactory recoveries ranging from 97.1 to 103.0%. This methodology offers a novel approach to underscore the potential of the developed sensor for applications in biological and pharmaceutical monitoring.

(Invited) Controlled Synthesis of Cocatalyst-Semiconductor Hybrid Nanomaterials for Photocatalytic Water Splitting

With the escalating global demand for energy, mitigating anthropogenic climate change necessitates the pursuit of carbon-neutral energy sources to diminish reliance on fossil fuels. Utilizing particulate photocatalysts for solar-light-driven water splitting presents a promising and sustainable paradigm for the large-scale production of storable and clean H2 fuel. To improve the solar energy conversion efficiency, coupling the photocatalysts with cocatalysts is a broadly adopted approach not only to facilitate charge separation and transport but also to serve as reaction sites and accelerate water-splitting reactions. Recent breakthroughs in colloidal synthesis enable the fabrication of advanced nanoparticles with precise control over size and composition. Colloidal NPs represent ideal cocatalyst candidates due to their capacity to provide numerous active sites and facilitate uninterrupted light absorption by the semiconductor. Here, we introduce our approach to synthesize cocatalyst-semiconductor hybrids as efficient photocatalysts, including the alloying of platinum group metal nanoparticle cocatalysts and the control of single-atom cocatalyst locations on semiconductor nanoparticles.Platinum group metals exhibit high efficiency as cocatalysts in the hydrogen evolution reaction, attributed to their favorable catalytic and electronic properties. Bimetallic alloy systems, in general, can considerably modulate their electronic structures, resulting in exceptional physicochemical properties surpassing those of their monometallic counterparts. Herein, we synthesized PtRu solid-solution alloy nanoparticles as high-performance H2 evolution reaction cocatalysts. The rational integration of PtRu nanoparticles with Al-doped SrTiO3 photocatalyst through liquid-phase adsorption and successive two-step annealing ensure the uniform deposition of PtRu alloy nanoparticles with a solid-solution structure. The bimetallic synergy between Pt and Ru induces higher electrocatalytic activity for the hydrogen evolution reaction and a superior electron-capturing property than its Pt counterpart. Modification of Al-doped SrTiO3 with PtRu alloy nanoparticles, CrOx, and CoOOH results in efficient photocatalytic overall water-splitting activity with an apparent quantum yield of 65% at 365 nm. This work introduces a framework to elucidate catalytic trends, offering rational design guidance for the development of bimetallic solid-solution nanoparticles as highly active cocatalysts for overall water splitting.Single-atom cocatalysts dispersed on semiconductor materials exhibit outstanding heterogeneous catalytic properties through the interactions between the single atoms and the photocatalyst. The nature of these interactions depends on whether the single atoms are located on the surface or within the interior of the photocatalyst. In this work, the location-selective placement of single atoms is achieved by carefully adjusting experimental procedure. Using CdSe nanoplatelets as a support, applying different Pt precursor complexes, solvent, and workup process resulted in location selective deposition of Pt atoms outside/inside CdSe nanoplatelet support. In photocatalytic hydrogen evolution reaction, the surface-adsorbed single Pt atoms exhibit higher stability than the substituted ones. This study provides a viable strategy for the structurally precise synthesis and design of single-atom catalysts.

(Invited) Development of Multifunctional Nanoscale Reactors for Electrocatalytic Oxidation of Dimethyl Ether Fuel

There has been growing interest in utilizing small (simple) organic molecules, as alternative fuels to hydrogen, for electrochemical energy conversion in fuel cells. Dimethyl ether (DME) is one of the possible choices in this respect. But electrooxidation of DME is rather slow at ambient conditions. Obviously, there is a need to develop novel electrocatalytic materials.Bimetallic PtSn catalysts were found to be almost as active as PtRu for methanol oxidation, and PtSn was even more efficient toward the electrooxidation of ethanol where breaking of C-C bond is required. While PtRu forms a single-phase homogeneous (intermetallic) alloy in which Ru is largely metallic, tin does not maintain its metallic state in PtSn (heterogenous alloy) and is transformed readily to such oxygenated species as Sn oxides or hydroxides. During operation of PtSn, the Pt component retains its mostly metallic character and act independently as Pt0 catalyst. By analogy to Ru, the Sn “bifunctional agent” tends to activate the water dissociative adsorption and increases population of chemisorbed hydroxyl groups to diminish the Pt-poisoning effect through enhanced oxidation of CO-type intermediates. Nevertheless, the DME oxidation on both PtRu or PtSn is still kinetically less favorable, relative to the systems’ performance toward methanol. While Sn, and particularly Ru alloyed atoms activate readily the water dissociative adsorption on Pt and permit the oxidative stripping of the poisoning CO-type adsorbates, the feasibility of the enhancement of the of the DME adsorption and activation through alteration of the electronic structure of Pt catalytic sites has not been fully explained. By analogy to the ethanol oxidation, Pt sites in the heterogeneous PtSn alloy are active toward dissociation of the DME molecule but the Sn additive is less efficient than Ru (from intermetallic PtRu) in the oxidative removal of poisoning adsorbates. But PtRu is probably the most active during oxidation of methanol, and this small organic molecule is also the DME-oxidation-reaction intermediate. Nevertheless, in comparison to bare Pt, electrooxidation of DME starts at PtRu and PtSn at less positive potentials.We pursue a concept of utilization of multicomponent hybrid electrocatalytic systems or nanoreactors utilizing zirconia oxide matrices for supporting and activation of primarily PtSn nanoparticles supported onto Vulcan XC-72 carbon black carriers. Electrocatalytic activity of Vulcan-supported PtSn (PtSn/V) nanostructured alloys supported onto ZrO2 matrices has been significantly enhanced toward electrooxidation of DME in acid medium (0.5 mol dm-3 H2SO4) by decorating PtSn/V with bimetallic PtRu nanoparticles. The enhancement effect concerns both shifting the onset potential for the DME-oxidation toward less positive values and increase of the DME electrocatalytic current densities recorded under both cyclic voltammetric and chronoamperometric conditions. The activating capabilities of ruthenium nanostructures seem to originate from the existence (even below 0.45 V vs. RHE) of reactive ruthenium oxo/ hydroxo groups on their surfaces capable of inducing the oxidative removal of poisoning (CO-type) adsorbates from the neighboring platinum catalytic sites. In this respect, the Ru-oxo species seem to support activity of Sn forming with Pt the PtSn heterogenous alloy. The PtSn/V admixed with PtRu decorated ZrO2 exhibit very high activity toward the oxidation of methanol which is also an important DME-oxidation intermediate. On the whole, the hybrid materials composed of Vulcan-supported PtSn decorated with Ru or PtRu nanoparticles decorated zirconia oxide seem to act as multifunctional nanoreactors inducing not only stripping of poisoning adsorbates but also catalyzing oxidation of the DME-reaction intermediates (methanol). Acknowledgement Authors acknowledge financial support of the National Science Center (Poland) under Opus Project 2018/29/B/ST5/02627.

(Invited) Smartphone-Based Nanosensors for Environmental, Food Safety, and Health Monitoring

: Biosensors are a modern engineering marvel with widespread applications across diverse areas, including healthcare, environmental monitoring, microbiology, and food safety and security. The integration of nanotechnology with biosensor technology has led to novel sensing mechanisms, significantly enhancing performance and sensing capabilities beyond the constraints of traditional methods. In our laboratory, several nanotechnology-enabled biosensors have been developed to overcome the limitations of current bioanalytical methods, particularly in terms of sensitivity, throughput, ease-of-use, and miniaturization. We have synthesized various innovative nanomaterials, such as protein cages, single-atom nanozymes, and mesoporous bimetal nanoparticles. These materials have been crucial in the fabrication of 3D printed nano-immunosensors, which are effective in detecting pesticides, food pathogens, and exposure biomarkers.My research specifically focuses on the development of nanotechnology-enhanced biosensors that leverage these novel nanomaterials. This endeavor aims to revolutionize biosensor fabrication, with a particular emphasis on creating new, handheld devices. These devices are designed for rapid, on-site detection of molecules, offering immense potential for point-of-care diagnostics. The integration of these biosensors with smartphone technology has further opened avenues for real-time data analysis and sharing, making them invaluable tools for environmental, food safety, and health monitoring. This talk will delve into the specifics of these developments, highlighting the innovative approaches and potential impacts of smartphone-based nanosensors in various sectors.

Restructuring dynamics of surface species in bimetallic nanoparticles probed by modulation excitation spectroscopy

Restructuring of metal components on bimetallic nanoparticle surfaces in response to the changes in reactive environment is a ubiquitous phenomenon whose potential for the design of tunable catalysts is underexplored. The main challenge is the lack of knowledge of the structure, composition, and evolution of species on the nanoparticle surfaces during reaction. We apply a modulation excitation approach to the X-ray absorption spectroscopy of the 30 atomic % Pd in Au supported nanocatalysts via the gas (H2 and O2) concentration modulation. For interpreting restructuring kinetics, we correlate the phase-sensitive detection with the time-domain analysis aided by a denoising algorithm. Here we show that the surface and near-surface species such as Pd oxides and atomically dispersed Pd restructured periodically, featuring different time delays. We propose a model that Pd oxide formation is preceded by the build-up of Pd regions caused by oxygen-driven segregation of Pd atoms towards the surface. During the H2 pulse, rapid reduction and dissolution of Pd follows an induction period which we attribute to H2 dissociation. Periodic perturbations of nanocatalysts by gases can, therefore, enable variations in the stoichiometry of the surface and near-surface oxides and dynamically tune the degree of oxidation/reduction of metals at/near the catalyst surface.

Green Synthesis of Silver Oxide-Nickel Oxide Bimetallic Nanoparticles Using Peels of Citrus Sinensis and their Application

Green Synthesis of Silver Oxide-Nickel Oxide Bimetallic Nanoparticles Using Peels of Citrus Sinensis and their Application

Eco-Friendly Synthesis, Characterization, and Biomedical Applications of Biosynthesized Bimetallic Silver-Gold Nanoparticles by Culture Supernatant of Aspergillus niger.

Green synthesis of bimetallic nanoparticles of noble metals is highly desirable in nanomedicine because of their potential use as anticoagulant, thrombolytic and anticancer agents. In this study, it was discovered that the filamentous fungus Aspergillus niger proved effective in producing bimetallic Ag-Au nanoparticles. A. niger culture supernatant was able to produce Ag-AuNPs by reducing the solution of chloroauric acid/silver nitrate (1.0:1.0 mM) within 2 min at 100 °C and pH 8. Experimental Ag-AuNP detection was performed by visually observing the color change to reddish brown. The produced nanoparticles displayed maximal absorbance at 530 nm in UV-vis spectroscopy. According to transmission electron microscopy, most of the nanoparticles were spherical, with a mean diameter of 8-10 nm. The biosynthesis of Ag-AuNPs by A. niger was confirmed by Fourier transform infrared spectroscopy, X-ray diffraction and energy dispersive X-ray analytical techniques. Its zeta potential was discovered to be -34.01 mV. The biosynthesized Ag-AuNPs exhibited effective thrombolytic and antiplatelet aggregation actions by totally preventing and dissolving the blood clot which was verified by microscopic examination, amelioration of blood coagulation assays, and carrageenan-induced tail thrombosis model. The findings verified the effectiveness of biosynthesized Ag-AuNPs as a powerful antitumor agent against HepG2 and A549 cell lines with IC50 values of 15.57 and 27.07 μg/mL, respectively. Crystal violet assay validated the cytopathic effects of Ag-AuNPs on A549 and HepG2 cell lines. Therefore, the produced Ag-AuNPs from A. niger are a promising candidate in the management of thrombosis.

Platinum-Ruthenium Bimetallic Nanoparticle Catalysts Synthesized Via Direct Joule Heating for Methanol Fuel Cells.

Platinum-Ruthenium (PtRu) bimetallic nanoparticles are promising catalysts for methanol oxidation reaction (MOR) required by direct methanol fuel cells. However, existing catalyst synthesis methods have difficulty controlling their composition and structures. Here, a direct Joule heating method to yield highly active and stable PtRu catalysts for MOR is shown. The optimized Joule heating condition at 1000°C over 50 microseconds produces uniform PtRu nanoparticles (6.32wt.% Pt and 2.97 wt% Ru) with an average size of 2.0 ± 0.5 nanometers supported on carbon black substrates. They have a large electrochemically active surface area (ECSA) of 239 m2 g-1 and a high ECSA normalized specific activity of 0.295mA cm-2. They demonstrate a peak mass activity of 705.9mA mgPt -1 for MOR, 2.8 times that of commercial 20 wt.% platinum/carbon catalysts, and much superior to PtRu catalysts obtained by standard hydrothermal synthesis. Theoretical calculation results indicate that the superior catalytic activity can be attributed to modified Pt sites in PtRu nanoparticles, enabling strong methanol adsorption and weak carbon monoxide binding. Further, the PtRu catalyst demonstrates excellent stability in two-electrode methanol fuel cell tests with 85.3% current density retention and minimum Pt surface oxidation after 24 h.