Effective Electron Transfer Research Articles

Facile Synthesis of Platinum Nanoparticle-Embedded Reduced Graphene Oxide for the Detection of Carbendazim.

In recent years, there has been a significant interest in the advancement of electrochemical sensing platforms to detect pesticides with high sensitivity and selectivity. Current research presents a novel approach utilising platinum nanoparticles (NPs) and reduced graphene oxide deposited on a glassy carbon electrode (Pt-rGO/GCE) for direct electrochemical measurement of carbendazim (CBZ). A straightforward one-step electrodeposition process was applied to prepare the Pt-rGO sensing platform. The incorporation of conductive rGO nanosheets along with distinctive structured Pt NPs significantly enhanced the effective electrode surface area and electron transfer of CBZ. Additionally, when exposed to 50 µM CBZ, Pt-rGO/GCE exhibited a higher current response compared to the bare electrode. Further investigations were performed to analyse and optimise the experimental parameters that could influence pesticide detection. Under the optimised conditions of pH 7 and 5 min of accumulation time, the Pt-rGO/GCE sensor showed a linear concentration detection range from 0.1 µM to 50 µM, with a detection limit of 3.46 nM. The fabricated sensor was successfully employed for CBZ detection in milk and tap water with 98.88% and 98.57% recovery, respectively. The fabricated sensor showed higher sensitivity and reproducibility, thus indicating the potential of this technology in the development of reliable sensors for the detection of CBZ or similar pesticides in forthcoming applications.

Tailoring the morphology of Mo2S3/MoP2 composite thin films via aerosol assisted chemical vapor deposition for enhanced hydrogen evolution reaction performance

In this study, we report on the fabrication of Mo2S3/MoP2 composite thin films using a single-step aerosol assisted chemical vapor deposition method from a single-source precursor solution of [(ƞ5-Cp)Mo(CO)2(S2P(SC6H4Me)2)] (1). Deposition times of 20, 30, and 40 min were used to obtain thin films with different morphologies. Our investigation found that the 30-minute thin film, which had a widely distributed grainy morphology, exhibited the highest electrocatalytic performance for hydrogen evolution reaction (HER) as determined by linear sweep voltammetry studies. This film required the lowest applied potential of 250 mV to generate a current density of 10 mAcm−2 with a low charge transport resistance of 715 Ω, despite having the lowest charge donor density of 5.52 × 1019 cm−3. We found that the unique morphology of this thin film enhanced electron mobility, resulting in superior HER performance with a Tafel slope of ∼123 mVdec−1 and a higher current charge density of 0.408 mAcm−2 due to increased active sites for HER. The Mo2S3/MoP2 heterostructure exhibited favourable band gaps of ∼2.2 and ∼2.7 eV, respectively, resulting in a synergistic effect that allowed for effective electron transfer. Our study concludes that different deposition durations produced composite thin films with altered morphologies that exhibit dissimilar electrochemical kinetics in HER.

Pt nanoclusters modified porous g-C3N4 nanosheets to significantly enhance hydrogen production by photocatalytic water reforming of methanol

For the use of green hydrogen energy, it is crucial to have efficient photocatalytic activity for hydrogen generation by water reforming of methanol under mild conditions. Much attention has been paid to g-C3N4 as a promising photocatalyst for the generation of hydrogen. To improve the separation of photogenerated charge, porous nanosheet g-C3N4 was modified with Pt nanoclusters (Pt/g-C3N4) through impregnation and following photo-induced reduction. This catalyst showed excellent photocatalytic activity of water reforming of methanol for hydrogen production with a 17.12 mmol·g−1·h−1 rate at room temperature, which was 311 times higher than that of the unmodified g-C3N4. The strong interactions of Pt–N in Pt/g-C3N4 constructed effective electron transfer channels to promote the separation of photo-generated electrons and holes effectively. In addition, in-situ infrared spectroscopy was used to investigate the intermediates of the hydrogen production reaction, which proved that methanol and water eventually turn into H2 and CO2via formaldehyde and formate. This study provides insights for understanding the photocatalytic hydrogen production in the water reforming of methanol.

Visible-light-driven Au/PCN-224/Cu(II) modified fabric with enhanced photocatalytic antibacterial and degradation activity and mechanism insight

The development of novel photocatalytic platform for efficient water purification and sterilization is of utmost importance due to the significant threat of chronic diseases resulting from water pollution and bacterial contamination. Herein, a high-efficiency, easy-recyclable, and environment-friendly photocatalytic fabric was developed as a water disinfection and organic pollutant degradation platform. In which, microamounts of Au nanoparticles (2 wt%) and Cu(II) clusters (2.5 wt%) co-decorated porphyrinic MOF (Au/PCN-224/Cu(II)) coating was applied as photocatalytic surface, and flexible cotton fabric served as stable support. Au/PCN-224/Cu(II) composite photocatalyst was prepared via a facile photo-deposition procedure followed by impregnation method, and further immobilized onto polydopamine (PDA) pre-treated cotton fabric through catechol-amine reaction. The fabricated photocatalytic platform exhibited excellent ability to generate reactive oxygen species (ROS) by multiple routes under low-power visible light irradiation, and achieved efficient photodisinfection effects for causative organism including Gram-negative Escherichia coli (E. coli) and Gram-positive Staphylococcus aureus (S. aureus) without the obvious leakage of metal ions from the potocatalyst during the reaction. Additionally, the reaction rate constant for organic dye MB photodegradation achieved by Au/PCN-224/Cu(II)@Fabric was 3.73 times higher than that of PCN-224@Fabric, and the degradation intermediates analysis was also conducted. The band alignments of PCN-224, Au/PCN-224, Au/PCN-224/Cu(II) photocatalysts were determined, and the charge transfer mechanism within Au/PCN-224/Cu(II) photocatalyst was elucidated through the utilization of DRS, Mott − Schottky, ESR, EIS, and photocurrent analyses. It is suggested that the deposition of Au and doping of Cu(II) both with small amounts enhanced the light absorption capacity, and also improved the charge separation ability through the surface plasmon resonance (SPR) effect and interfacial electron transfer (IFCT) mechanism. Moreover, Au SPR and Cu doping exhibited a substantial enhancement in photothermal conversion effect, thereby synergistically reinforcing the sterilization performance. This work provides an approach for the development of effective photocatalytic platform based on porphyrinic MOFs combined with trace metal co-catalysts in the application of water disinfection and purification.

Enhanced Visible Light-Driven Photocatalytic Water-Splitting Reaction of Titanate Nanotubes Sensitised with Ru(II) Bipyridyl Complex.

The ion exchange of Na+ cations was used to photosensitise titanates nanotubes (Ti-NTs) with tris(2,2'-bipyridine)ruthenium(II) cations (Ru(bpy)32+); this yielded a light-sensitised Ti-NTs composite denoted as (Ru(bpy)3)Ti-NTs, exhibiting the characteristic absorption of Ru(bpy)32+ in visible light. Incident photon-to-current efficiency (IPCE) measurements and the photocatalytic reduction of methyl viologen reaction confirmed that in the photosensitisation of the (Ru(bpy)3)Ti-NTs composite, charge transfer and charge separation occur upon excitation by ultraviolet and visible light irradiation. The photocatalytic potential of titanate nanotubes was tested in the water-splitting reaction and the H2 evolution reaction using a sacrificial agent and showed photocatalytic activity under various light sources, including xenon-mercury lamp, simulated sunlight, and visible light. Notably, in the conditions of the H2 evolution reaction when (Ru(bpy)3)Ti-NTs were submitted to simulated sunlight, they exceeded the photocatalytic activity of pristine Ti-NTs and TiO2 by a factor of 3 and 3.5 times, respectively. Also, (Ru(bpy)3)Ti-NTs achieved the photocatalytic water-splitting reaction under simulated sunlight and visible light, producing, after 4 h, 199 and 282 μmol×H2×gcat-1. These results confirm the effective electron transfer of Ru(bpy)3 to titanate nanotubes. The stability of the photocatalyst was evaluated by a reuse test of four cycles of 24 h reactions without considerable loss of catalytic activity and crystallinity.

A bimetallic organic framework based fluorescent aptamer probe for the detection of zearalenone in cereals

In this work, a bimetallic organic framework (Cu/UiO-66) based “turn on” fluorescent aptamer probe was designed for the high-efficiency detection of zearalenone (ZEN). In the probe, the 6-carboxyfluorescein-labeled aptamer (FAM-Apt) was used as the recognition element, and the electrostatic interaction, coordination effect, and photoinduced electron transfer effect between FAM-Apt and Cu/UiO-66 caused fluorescence quenching. When ZEN existed, FAM-Apt recognized ZEN specifically, causing FAM-Apt to separate from the surface of Cu/UiO-66 and recovery of fluorescence. Under the optimal conditions, the probe had a linear detection range of 0.5 ng/mL–60 ng/mL, and the detection limit was 0.048 ng/mL. The application potential of the probe was verified by real detection of various cereals and their products, with a standard recovery from 83.67 %–106.8 %. The development of this efficient, rapid, and sensitive ZEN detection method provides a new platform for the quality control of cereals and their products.

Activation of peroxymonosulfate for ciprofloxacin degradation by a novel oxygen-deficient CoTiO3/TiO2NTs/Ti composite catalytic membrane:Electron transfer pathway and underlying mechanism

The technique of activating peroxymonosulfate (PMS) by enriching oxygen vacancies (Vo) in heterogeneous catalysts has gained extensive attentions in the removal of emerging contaminants, e.g., antibiotics from wastewater. In this study, a Vo-CoTiO3/TiO2NTs/Ti (Vo-CTNs) catalytic membrane with rich oxygen vacancies was prepared and employed for the activation of PMS in degrading ciprofloxacin (CIP) in a continuous flow reactor. The averaged degradation efficiency of CIP in the Vo-CTNs/PMS system could reach 97.3 %, significantly higher than that in the CoTiO3/TiO2NTs/Ti (CTNs) system (91.1 %). Quenching experiments and electron paramagnetic resonance analysis collectively confirmed the presence of •OH, SO4•−, O2•− and 1O2 during the CIP degradation process. The results of the electrochemical experiments demonstrated that in the presence of oxygen vacancies, the mutual conversion between Co2+ and Co3+ was facilitated, resulting in a lower transfer resistance. At an initial CIP concentration of 10 mg/L and a membrane flux of 600 LMH, the degradation efficiency and mineralization rate of CIP could reach 95.2 % and 51.1 % after 12 h of operation, respectively. Meanwhile, limited leaching of cobalt ions (52 μg/L) from the catalytic membrane was observed during treatment. Theoretical calculations revealed that Vo engineering can modulate the surface electronic states, thereby enhancing binding energy and electron transfer for PMS activation. The degradation of CIP is mainly achieved through the ring opening reactions in the piperazine, quinolone, and cyclopropyl groups attacked by reactive oxygen species. In this work, we built cobalt-based composite nanomaterials to promote effective electron transfer and minimize leaching of cobalt ions, and providing a new method for activating PMS in a continuous flow system by enriching the oxygen vacancies in the catalytic membrane. This method has potentials to be applied in treating wastewater containing antibiotics such as CIP.

Bi-directional regulation of electroactive microbial community using Au/antimicrobial peptide nanocomposite

The power generation and pollutants removal efficiencies of mixed electroactive microbial community rely on the effective electron transfer between outer membrane proteins of electroactive electricigens. However, the poor conductivity of protein and various non-electrogenic bacteria greatly hinder the electron transfer and effective contact between electricigens. Herein, we report a novel “bi-directional” microbial community regulation method that can selectively inhibit Gram-positive non-electrogenic bacteria and enhances the conductivity and electron transfer between electrogenic bacteria and the electrode in MFC by taking the advantages of the excellent conductive and bacteriostatic properties of Au/Nisin nanocomposite. The Au/Nisin stimulation endows microbial fuel cell (MFC) a high-efficiency functional community, which increases the power density and decolorization rate by 103 % and 33 %, respectively. The high conductivity, and selectivity and antimicrobial activity of the nanocomposite improve the electrochemical activity of the bioanode, hereby promoting the microbial extracellular electron transfer and increasing the proportion of electrogenic bacteria such as Proteobacteria, Bacteroidetes and Desulfovibrio in the biofilm. Our work successfully demonstrates that the construction of multifunctional metallic peptide nanocomposite can effectively regulate microbial community to improve the electrochemical performance of MFC.

Enhanced tetracycline degradation by a confinement structure rGO/Fe1/C3N4 photocathode during the sequential oxygen reduction process

Photoelectrocatalytic (PEC) process based on hydroxyl radicals (•OH) can effectively remove refractory pollutants, however, reducing molecular oxygen to •OH by a PEC process remains a challenge. In this work, an atomically dispersed Fe catalyst (rGO/Fe1/C3N4) was proposed. The rGO/Fe1/C3N4 photocathode showed high efficiency (88.3%, 60 min) and low energy consumption (0.072 kWh/g) in removing tetracycline (TC), and •OH was the main active species for TC degradation. The results of experimental and theoretical calculations revealed that the efficient TC degradation is due to the coupling effect of rGO and Fe atoms. The rGO enhances light absorption and effective electron transfer, thus facilitating the reduction of O2 to H2O2. Subsequently benefiting from the low H2O2 adsorption energy on Fe single atoms, enhanced electron and mass transfer between Fe single atoms and the coordination environment, H2O2 is further reduced to •OH in the confinement structure. Stability test and toxicity analysis in TC degradation demonstrate that the PEC process is an environmentally friendly technology that is stable in the long term. This work provides a new idea for designing photoelectrocatalysts with excellent •OH generation and TC degradation capacity.

Sonochemical Synthesis, Characterization, and Photocatalytic Performance Evaluation of Au/ZnO Nanocomposite for Methyl Orange Degradation

This study examines the impact of gold (Au) incorporation on zinc oxide (ZnO) nanoparticles. Both pure ZnO and Au/ZnO nanocomposite have been synthesized using a unique and environmentally friendly sonochemical approach. The as-synthesized Au/ZnO nanocomposite was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and ultraviolet-visible (UV-vis) spectroscopic techniques. Under UV-visible irradiation, the photocatalytic effectiveness of ZnO nanoparticles and Au/ZnO nanocomposites for the degradation of dye was examined. The results demonstrated that the nanocomposite has greater photocatalytic activity than ZnO nanoparticles. This is due to the effective electron transfer from ZnO to Au prolonging the lifetime of photogenerated holes, which play the most important role in the dye degradation process.

Recent Progress in Using Mesoporous Carbon Materials as Catalyst Support for Proton Exchange Membrane Fuel Cells.

Developing durable oxygen reduction reaction (ORR) electrocatalysts is essential to step up the large-scale applications of proton exchange membrane fuel cells (PEMFCs). Traditional ORR electrocatalysts provide satisfactory activity, yet their poor durability limits the long-term applications of PEMFCs. Porous carbon used as catalyst support in Pt/C is vulnerable to oxidation under high potential conditions, leading to Pt nanoparticle dissolution and carbon corrosion. Thus, integrating Pt nanoparticles into highly graphitic mesoporous carbons could provide long-term stability. This Perspective seeks to reframe the existing approaches to employing Pt alloys and mesoporous carbon-integrated ORR electrocatalysts to improve the activity and stability of PEMFCs. The unusual porous structure of mesoporous carbons promotes oxygen transport, and graphitization provides balanced stability. Furthermore, the synergistic effect between Pt alloys and heteroatom doping in mesoporous carbons not only provides a great anchoring surface for catalyst nanoparticles but also improves the intrinsic activity. Furthermore, the addition of Pt alloys into mesoporous carbon optimizes the available surface area and creates an effective electron transfer channel, reducing the mass transport resistance. The long-term goals for fuel-cell-powered cars, especially those designed for heavy-duty use, are well aligned with the results shown when this hybrid material is used in PEMFCs to improve performance and durability.

Covalently linked graphene oxide-transition metal disulfide quantum dots nanocomposites featuring enhanced nonlinear optical absorption

Nanocomposites composed of different nanomaterials are a promising class of optoelectronic materials, owing to their interfacial electronic interactions. Compared to van der Waals forces, covalent bond-based linkages may endow nanocomposites with promoted electronic interactions and reinforced nonlinear optical (NLO) responses. In this study, we constructed covalently linked, mixed-dimensional nanocomposites by combining graphene oxide (GO) with MoS2 and WS2 quantum dots (QDs). These nanocomposites were prepared by employing a bifunctional molecule, 4-mercaptobenzenediazonium tetrafluoroborate, which carries a reactive diazonium group and a thiol group. The reactive diazonium group allowed for the attachment of thiophenol to GO via a radical addition reaction, while the thiol group enabled the subsequent passivation of sulfur vacancies in MoS2 and WS2 QDs. The resulting nanocomposites, denoted as GO-MoS2 and GO-WS2, respectively, exhibited significant fluorescence quenching, indicating effective electron and/or energy transfer from MoS2 or WS2 QDs to GO. Importantly, these covalently linked nanocomposites demonstrated superior two-photon absorption (TPA) responses compared to the individual components (GO, MoS2 and WS2 QDs) as well as the corresponding physical blends, presumably resulting from the efficient electron and/or energy transfer within these nanocomposites. This study not only demonstrates the significant promise of covalently linked GO-MoS2 and GO-WS2 nanocomposites in optical limiting applications, but also opens up new opportunities for the advancement of nanocomposites in ultrafast photonic devices.

Construction of flower-like spherical CoFe2O4@Co3O4 based on zeolitic imidazolate framework as high-performance electrode materials for supercapacitors

Ferrite, a class of transition metal oxides, has emerged as a promising material for electrochemical energy storage due to its cost-effectiveness and high theoretical capacity. However, the tendency of ferrite to agglomerate hinders its practical application. Here, we report a facile method to fabricate CoFe2O4@Co3O4 flower-like sphere and form a unique core-shell structure. In this composite, flake Co3O4 pile up to form shell which cladding the CoFe2O4 core. Crumpled shell provide ultra-high specific surface area (128.54 m2/g) to expose more electrochemical active sites, benefiting effective electrons transfer. As a result, the optimized flower-like spherical structure electrode exhibited an exceptionally high capacity of 2834 F g−1 at a current density of 1 A g−1. Additionally, the electrode demonstrated outstanding rate capability, retaining 78 % of its capacity at a current density of 10 A g−1.

Direct observation of chirality-induced spin selectivity in electron donor-acceptor molecules.

The role of chirality in determining the spin dynamics of photoinduced electron transfer in donor-acceptor molecules remains an open question. Although chirality-induced spin selectivity (CISS) has been demonstrated in molecules bound to substrates, experimental information about whether this process influences spin dynamics in the molecules themselves is lacking. Here we used time-resolved electron paramagnetic resonance spectroscopy to show that CISS strongly influences the spin dynamics of isolated covalent donor-chiral bridge-acceptor (D-Bχ-A) molecules in which selective photoexcitation of D is followed by two rapid, sequential electron-transfer events to yield D•+-Bχ-A•-. Exploiting this phenomenon affords the possibility of using chiral molecular building blocks to control electron spin states in quantum information applications.

Efficient charge transfer at the donor-bridge-acceptor interface for excellent supercapacitors

The intrinsic electrochemical activity and active sites of the battery-like electrode in supercapacitors originate from efficient charge transfer at the interface. A seamless all-carbon graphdiyne layer on CoNi2S4 yolk-shell spheres (CoNi2S4/GDY YSSs) provides a unique structure of a flawless “donor–bridge–acceptor” interface, where Ni atoms and Co atoms serve as electron donors and acceptors, respectively, connected by the sp-C–Ni and sp-C–Co bonds as bridges. Importantly, this particular can facilitate effective electron transfer from the Ni atoms to the Co atoms, resulting in more interfacial Co2+ active sites and reversible redox coupling of Co-S/Co-S-OH and Co-S-OH/Co-S-O to increase the specific capacitance. Additionally, the seamless all-carbon graphdiyne layer greatly enhances the structural and interfacial stability of CoNi2S4 yolk-shell spheres, effectively avoiding structural deterioration to enhance cycling stability performance. Profiting from its structural merits, the CoNi2S4/GDY YSSs electrode delivers a considerable capacitance of 856C/g at 1 A/g, along with exceptional rate capability (61.9 % for 50-fold current density increase). Furthermore, an asymmetric supercapacitor with the CoNi2S4/GDY YSSs electrode cathode achieves a remarkable maximum energy density of 91.7 Wh/kg at a power density of 793 W/kg. Furthermore, the strategy proposed in this study has the potential to open up new pathways for the battery-like electrode design with realistic supercapacitor applications.

Carbon-Based Electron Buffer Layer on ZnOx-Fe5C2-Fe3O4 Boosts Ethanol Synthesis from CO2 Hydrogenation.

The conversion of CO2 into ethanol with renewable H2 has attracted tremendous attention due to its integrated functions of carbon elimination and chemical synthesis, but still being challenging. The electronic property of catalyst is essential to determine the adsorption strength and configuration of the key intermediates, therefore altering the reaction network for targeted synthesis. Here, a carbon buffer layer is employed to tailor the electronic property of the ternary ZnOx-Fe5C2-Fe3O4, in which the electron transfer pathway (ZnOx → Fe species or carbon layer) ensures the appropriate adsorption strength of -CO* on catalytic interface, facilitating the C-C coupling between -CHx* and -CO* for ethanol synthesis. Benefiting from this unique electron transfer buffering effect, extremely high ethanol yield of 366.6 gEtOH kgcat-1 h-1 (with CO of 10 vol% co-feeding) is achieved from CO2 hydrogenation. This work provides a powerful electronic modulation strategy for catalyst design in terms of highly oriented synthesis.

Use of QM/MM Surface Hopping Simulations to Understand Thermally Activated Rare-Event Nonadiabatic Transitions in the Condensed Phase.

We implement a rare-event sampling scheme for quantifying the rate of thermally activated nonadiabatic transitions in the condensed phase. Our Quantum mechanics/molecular mechanics (QM/MM) methodology uses the recently developed Interface for NonAdiabatic QM/MM in Solvent (INAQS) package to interface an elementary electronic structure package and a popular open-source molecular dynamics software (GROMACS) to simulate an electron transfer event between two stationary ions in a solution of acetonitrile solvent molecules. Nonadiabatic effects are implemented through a surface hopping scheme, and our simulations allow further quantitative insight into the participation ratio of a solvent and the effect of ion separation distance as far as facilitating electron transfer. We also demonstrate that the standard gas-phase approaches for treating frustrated hops and velocity reversal must be refined when working in the condensed phase with many degrees of freedom. The code and methodology developed here can be easily expanded upon and modified to incorporate other systems and should provide a great deal of new insight into a wide variety of condensed phase nonadiabatic phenomena.

Absence of electron-transfer-associated changes in the time-dependent X-ray free-electron laser structures of the photosynthetic reaction center.

Using the X-ray free-electron laser (XFEL) structures of the photosynthetic reaction center from Blastochloris viridis that show light-induced time-dependent structural changes (Dods et al., (2021) Nature 589, 310-314), we investigated time-dependent changes in the energetics of the electron-transfer pathway, considering the entire protein environment of the protein structures and titrating the redox-active sites in the presence of all fully equilibrated titratable residues. In the dark and charge separation intermediate structures, the calculated redox potential (Em) values for the accessory bacteriochlorophyll and bacteriopheophytin in the electron-transfer-active branch (BL and HL) are higher than those in the electron-transfer-inactive branch (BM and HM). However, the stabilization of the charge-separated [PLPM]•+HL•- state owing to protein reorganization is not clearly observed in the Em(HL) values in the charge-separated 5 ps ([PLPM]•+HL•- state) structure. Furthermore, the expected chlorin ring deformation upon formation of HL•- (saddling mode) is absent in the HL geometry of the original 5 ps structure. These findings suggest that there is no clear link between the time-dependent structural changes and the electron-transfer events in the XFEL structures.

Absence of electron-transfer-associated changes in the time-dependent X-ray free-electron laser structures of the photosynthetic reaction center

Using the X-ray free-electron laser (XFEL) structures of the photosynthetic reaction center from Blastochloris viridis that show light-induced time-dependent structural changes (Dods et al., (2021) Nature 589, 310–314), we investigated time-dependent changes in the energetics of the electron-transfer pathway, considering the entire protein environment of the protein structures and titrating the redox-active sites in the presence of all fully equilibrated titratable residues. In the dark and charge separation intermediate structures, the calculated redox potential (Em) values for the accessory bacteriochlorophyll and bacteriopheophytin in the electron-transfer-active branch (BL and HL) are higher than those in the electron-transfer-inactive branch (BM and HM). However, the stabilization of the charge-separated [PLPM]•+HL•– state owing to protein reorganization is not clearly observed in the Em(HL) values in the charge-separated 5 ps ([PLPM]•+HL•– state) structure. Furthermore, the expected chlorin ring deformation upon formation of HL•– (saddling mode) is absent in the HL geometry of the original 5 ps structure. These findings suggest that there is no clear link between the time-dependent structural changes and the electron-transfer events in the XFEL structures.

Core-shell-shell nanocomposites structured polyaniline-rGO coated copolymer of NiFe2O4@poly(aniline-co-pyrrole) for sensitive Co2+ detection

A two-step in situ chemical polymerization approach that involved the simple in-situ oxidative polymerization of (ANI-co-Py) as a copolymer on NF nanoparticle NPs, followed by the succeeding in-situ oxidative polymerization of ANI-rGO on the P(ANI-co-Py)/NF core–shell structure, has successfully obtained a shell of polyaniline (PANI)- reduced graphene oxide (rGO) on poly(aniline-co-pyrrole)/NiFe2O4/P(ANI-co-Py)/NF core–shell. The resulting PANI-rGO/P(ANI-co-Py)/NF NCs consist of NiFe2O4 nanoparticles that acted as the “core” surrounding conducting copolymers, while the intermediate rGO serves as the bridge network connecting the copolymer and PANI, offering good structural stability as well as an effective electron transfer pathway. Moreover, the produced nanocomposite NCs also exhibit the core shell-shell structure with the features of electrode materials. A reliable sensor selective to Co2+ ion has been developed based on the high structural and compositional properties of the as-obtained PANI-rGO/P(ANI-co-Py)/NF NCs. Where a glassy carbon electrode (GCE) was coated by a slurry of synthesized PANI-rGO/P(ANI-co-Py)/NF NCs, which was stabilized using a suspension of Nafion (5 % suspension in ethanol) as a binding agent. A calibration curve of the current data and the corresponding concentrations of Co2+ ions have been established. From the calibration curve, the reliability of the linear dynamic range (0.1 nM–0.01 mM), the sensor sensitivity (204.2658 µA.µM−1.cm−2), and the lower limit of detection (99.27 ± 4.96 pM) have evaluated. Finally, the designed sensor was subjected to examining real environmental samples, where the fabricated sensor exhibited a successful high reproducibility. Recently, the development of sensors based on nanocomposites of organometallic on GCE has become key in the field of sensor development. The simple rapid synthesis of the PANI-rGO/P(ANI-co-Py)/NF NCs sensor will considerably contribute to the field of sensor management. In addition, the good performance of the PANI-rGO/P(ANI-co-Py)/NF NCs electrodes has drawn attention to them as promising electrode materials for high-performance sensors.