Incorporation Of Metal Nanoparticles Research Articles

Photoresponsivity enhancement of W-doped ZnO film/Silicon based devices via silver nanoparticles

Silver nanoparticles (Ag NPs) were deposited onto a 2 at.% Tungsten (W)-doped ZnO (WZO)/p-Silicon (p-Si) UV photodetector using a cost-effective sol–gel method. Top-view scanning electron microscopy (SEM) images confirmed the uniform coating of Ag NPs. Cross-sectional SEM analysis revealed a WZO film thickness of 167 nm, including the Ag NP layer. UV–Vis spectroscopy demonstrated high transparency with an average value of 79.5% for the Ag NPs-coated WZO film. The bandgap energy of this film was calculated to be 3.17 eV. The fabricated photodetector, comprising the Ag NP-modified WZO film and p-Si substrate, exhibited superior performance due to enhanced optical and electrical properties. Notably, the device achieved a responsivity (R*) of 4.83 A/W, a sensitivity (S*) of 60.82, and a detectivity (D*) of 5.06 × 1012 Jones. Compared to the unmodified WZO/p-Si device, the Ag NP-coated photodetector displayed significant improvements: a 26% increase in R*, a 79% increase in S*, and a 53% increase in D*. These findings highlight the potential of incorporating metal nanoparticles into photosensitive devices to optimize light-matter interactions.

Enhanced surface emission of bismuth-ion doped glass by adding metal nanoparticles

Enhancing the luminescent properties of doped silica glass has garnered significant interest due to its potential applications in photonics and optoelectronics. In this study, we enhance the surface emission of bismuth(Bi)-doped silica glass by incorporating metal nanoparticles. Utilizing finite-difference time-domain (FDTD) simulations, we observed a significant increase in surface emission following population inversion. We developed a novel algorithm to achieve a uniform distribution of nanoparticles in a two-dimensional computational model, ensuring that the distribution is physically accurate. Through systematic investigation, we explored the effects of the number, distribution, and size of silver nanoparticles on the surface emission enhancement of Bi-doped glass. Our results demonstrate that under optimal conditions, the surface emission enhancement can reach nearly 72%. Additionally, we evaluated the impact of various metal nanoparticles, finding that gold, silver, copper, and platinum positively influence surface emission enhancement, while titanium has an inhibitory effect. This study underscores the potential of metal nanoparticles to significantly improve the luminescent properties of doped glass, paving the way for advanced applications in photonic devices.

Enhanced efficiency of carbon based all perovskite tandem solar cells via cubic plasmonic metallic nanoparticles with dielectric nano shells

This study investigates a carbon-based all-perovskite tandem solar cell (AP-TSC) with the structure ITO, SnO₂, Cs₀.₂FA₀.₈Pb(I₀.₇Br₀.₃)₃, WS₂, MoO₃, ITO, C₆₀, MAPb₀.₅Sn₀.₅I₃, PEDOT: PSS, Carbon. The bandgap configuration of the cell is 1.75 eV/1.17 eV, which is theoretically limited to 36% efficiency. The effectiveness of embedding cubic plasmonic metallic nanoparticles (NPs) made of Gold (Au) and Silver (Ag) within the absorber layers to eliminate the requirement for thicker absorber layers, decrease manufacturing costs and Pb toxicity is demonstrated in our analysis. This analysis was conducted using 3D Finite Element Method (FEM) simulations for both optical and electrical calculations. Prior to delving into the primary investigation of the tandem structure, a validation simulation was conducted to demonstrate the accuracy and reliability of the simulations. Notably, the efficiency mismatch observed during the validation simulation, specifically in relation to the incorporation of metallic nanoparticles (NPs), amounted to a mere 0.01%. To mitigate the potential issues of direct contact between metallic NPs and perovskite materials, such as increased thermal and chemical instability and recombination at the NP surface, a 5 nm dielectric shell was applied to the NPs. The incorporation of cubic core-shell Ag NPs resulted in a 15.32% enhancement in short-circuit current density, from 16.39 mA/cm² to 18.90 mA/cm², and a 15.68% increase in overall efficiency, from 26.9 to 31.12%. This research paves the way for the integration of core-shell metallic NPs in AP-TSCs, highlighting a significant potential for efficiency and stability improvements. In a dedicated section the band alignment of the sub-cell was addressed. Additionally, a thermal investigation of the proposed tandem structure was conducted, demonstrating the robustness of the proposed AP-TSC. Finally, the sensitivity analyses related to input parameters and the challenges associated with large-scale fabrication of the proposed AP-TSC were extensively discussed.

Chitosan-grafted Graphene Materials for Drug Delivery in Wound Healing.

The effective and prompt treatment of wounds remains a significant challenge in clinical settings. Consequently, recent investigations have led to the development of a novel wound dressing production designed to expedite the process of wound healing with minimal adverse complications. Chitosan, identified as a natural biopolymer, emerges as an appealing option for fabricating environmentally friendly dressings due to its biologically degradable, nonpoisonous, and inherent antimicrobial properties. Concurrently, graphene oxide has garnered attention from researchers as an economical, biocompatible material with non-toxic attributes for applications in wound healing. Chitosan (CS) has been extensively studied in agglutination owing to its advantageous properties, such as Non-toxicity biological compatibility, degradability, and facilitation of collagen precipitation. Nonetheless, its limited Medium mechanical and antibacterial strength characteristics impede its widespread clinical application. In addressing these shortcomings, numerous researchers have embraced nanotechnology, specifically incorporating Metal nanoparticles (MNPs), to enhance the mechanical power and targeted germicide features of chitosan multistructures, yielding hopeful outcomes. Additionally, chitosan is a decreasing factor for MNPs, contributing to reduced cytotoxicity. Consequently, the combination of CS with MNPs manifests antibacterial function, superior mechanical power, and anti-inflammatory features, holding significant potential to expedite wound healing. This study delves into Based on chitosan graphene materials in the context of wound healing.

Electrochemical remediation of methyl orange over reusable biochar ferrite coated photocatalytic plates

Biochar (BC) obtained from biomass pyrolysis holds immense potential for environmental remediation. The efficiency of BC can further be enhanced by incorporating metal nanoparticles (NPs) in the porous carbon matrix. In the present work nanocomposites (NCs) were prepared by the addition of ferrite nanoparticles (FNPs) into an oxidized BC matrix to create BC /Fe3O4 (BCF). This process improves BC stability, electron transfer, conductivity, and photocatalytic ability for dye degradation. Microstructure and functional group analysis of BCF was performed by SEM, XRD, and FTIR showing intercalation of FNPs with surface functionalities of oxidized BC matrix. The B-H curve of FNPs and BCF reveals super paramagnetic behavior with saturation magnetization (Ms, emu/g) of 67.36 and 20.01 respectively. BET surface area analysis shows surface area (m2/gm) 45.81 and 44.19 for oxidized BC and BCF respectively, that attributed to partial blocking of porous carbon matrix by FNPs. UV-DRS supports the semiconducting behavior of BCF with a significantly reduced band gap (eV) of 2.95 over pristine BC (4.76). BCF-coated photocatalytic plates (PCPs) were developed and utilized for the remediation of methyl orange (MeO) in water samples. Degradation of MeO was investigated over time by electrochemical methods. The square wave voltammetric method showed the limit of detection and quantification of 0.09 ppm and 0.28 ppm respectively for MeO over a glassy carbon electrode in 0.1 M acetate buffer. BCF-derived PCPs rendered ∼99 % degradation efficiency against MeO (50 mgL−1) under UV radiation over 240 min. Developed PCPs demonstrate reusability up to 5 cycles without any further purification step and offer efficient degradation of MeO making them suitable for the treatment of water polluted with dyes.

Promotion of Probabilistic Bit Generation in Mott Devices by Embedded Metal Nanoparticles.

Considerable attention has been drawn to the use of volatile two-terminal devices relying on the Mott transition for the stochastic generation of probabilistic bits (p-bits) in emerging probabilistic computing. To improve randomness and endurance of bit streams provided by these devices, delicate control of the transient evolution of switchable domains is required to enhance stochastic p-bit generation. Herein, it is demonstrated that the randomness of p-bit streams generated via the consecutive pulse inputs of pump-probe protocols can be increased by the deliberate incorporation of metal nanoparticles (NPs), which influence the transient dynamics of the nanoscale metallic phase in VO2 Mott switches. Among the vertically stacked Pt-NP-containing VO2 threshold switches, those with higher Pt NP density show a considerably wider range of p-bit operation (e.g., up to ≈300% increase in ΔVprobe upon going from (Pt NP/VO2)0 to (Pt NP/VO2)11) and can therefore be operated under the conditions of high speed (400 kbit s-1), low power consumption (14 nJ per bit), and high stability (>105200 bits) for p-bit generation. Thus, the study presents a novel strategy that exploits nanoscale phase control to maximize the generation of nondeterministic information sources for energy-efficient probabilistic computing hardware.

Synergistic effects of TiO2-ZnO/Poly(methyl methacrylate) nanocomposite films: Enhanced wettability, antimicrobial activity, and biocompatibility

The poly (methyl methacrylate) (PMMA) nanocomposite films were fabricated using a cost-effective solvent evaporation method. The dominance of the wurtzite Zinc oxide (ZnO) phase was observed, accompanied by a suppression in the phase intensity of anatase titanium dioxide (TiO2) in the PMMA matrix confirmed by the XRD. New peaks appeared at 1651 cm−1 for the Ti-OH of TiO2 and 590 cm−1 for the metal–oxygen vibration of ZnO in the nanocomposite films. SEM micrograph of the TZPMMA resulted in the formation of nanopores with the nanoparticles embedded in the PMMA matrix. The wettability was enhanced by 23 % with the incorporation of metallic nanoparticles. Zinc ions increased antimicrobial susceptibility against S. aureus by 20 % more than E. coli, demonstrating the potential for fighting bacterial infections. The porous surface created by the nanoparticles improved the cell viability of the PMMA. Zebrafish embryo mortality percentage (0.5 %) and cell viability percentage (80 %) against human gingival fibroblasts (hGFs) showed that the incorporation of metal oxides made the PMMA, a potential candidate for biomedical applications.

Remarkably enhancing dielectric permittivity and suppressing loss of PVDF via incorporating metal nanoparticles decorated glass fibers

Dielectrics with high permittivity and low dielectric loss have so far received considerable attention because of their wide applications in various electronic devices. However, the enhanced permittivity of dielectrics is always accompanied by an increase in loss. In this work, targeting at enhancing the permittivity of poly(vinylidene fluoride) (PVDF) without elevating loss, gold nanoparticles (Au NPs) decorated glass fibers (GF) are incorporated into the PVDF, forming a unique design of Au@GF/PVDF composites. The effects of gold nanoparticle content, calcination temperature, and hot-pressing pressure on the dielectric properties are studied. Interestingly, for the composite with gold sputtering time of 3 min, a remarkable dielectric enhancement of 430% (i.e. from 7.8 to 33.5 at 10 kHz) along with an obvious loss suppression of 56% (i.e. from 0.0353 to 0.0198) are concurrently achieved. It is believed that, the increase in permittivity is mainly attributed to the Maxwell–Wagner–Sillars effect of effective micro-capacitors and cluster polarization of gold nanoparticles while the suppressed loss is originated from the intrinsic low loss of GF and the Coulomb-blockade effect of gold nanoparticles. This work offers a promising strategy to simultaneously enhance the permittivity and suppress the loss of dielectric materials.

Hierarchical zeolite-encapsulated metal nanoparticles for heterogeneous catalysis.

Zeolites, characterized by their highly porous structure, have become integral to modern industry and environmental science due to their broad applications in adsorption, separation, and catalysis. Recent advancements in zeolite synthesis, particularly through hydrothermal methods and the incorporation of metal nanoparticles, have significantly expanded their utility. This review delves into the innovative strategies for encapsulating metal nanoparticles within zeolite matrices, enhancing catalytic reactions' efficiency, selectivity, and durability. Challenges such as nanoparticle agglomeration and catalyst deactivation are addressed through hierarchical zeolite encapsulation, which provides a novel route for the development of multifunctional materials. By examining methods ranging from in situ encapsulation to post-synthetic recrystallization, this review highlights the versatility and potential of metal@zeolite catalysts in various applications, including organic synthesis, pollutant treatment, and energy conversion. The review underscores the importance of optimizing the interaction between metal nanoparticles and the zeolite framework to achieve superior catalytic performance, offering new directions for research in catalytic science and industrial process optimization.

Using Ag nanoparticles in the electron transport layer of perovskite solar cells to improve efficiency

The incorporation of metal nanoparticles within various types of photovoltaic technologies has been shown to increase the performance of organic solar cells, dye sensitized solar cells, and more recently perovskite solar cells. Using this type of nanostructured composite transport layer could help improve the efficiency and stability of perovskite solar cells whilst avoiding the use of dopants that can damage the perovskite layer. In this work, Ag nanoparticles are synthesized and used to form a SnO2:Ag nanoparticle composite transport layer for the first time. On its own, SnO2 is in one of the most efficient transport layers for perovskite solar cells. Upon inclusion of the Ag nanoparticles the recombination rate is increased (detrimental for device performance) as shown by impedance spectroscopy, and the charge carrier transfer and extraction is enhanced (beneficial for device performance) as shown by photoluminescence measurements. In order to balance these opposing factors, the nanoparticle concentration was optimized at an intermediate concentration with a corresponding power conversion efficiency increase from 13.4 ± 0.7 % for reference solar cells without nanoparticles to 14.3 ± 0.3 % for those with nanoparticles. These devices are one of the first examples of, and exhibit the highest reported efficiency for, perovskite solar cells fabricated completely in air with nanocomposite oxide layers. The protocol developed and reported here to improve the nanocomposite transport layer has general applicability in other fields, including LEDs, FETs, and electronic devices where transparency and conductivity are also required.

Advancements in Enhancing Antibacterial Properties of Cotton Fabric through Chitosan and Nanoparticles

AbstractOver recent years, the garment industry has been actively seeking innovative solutions to address critical challenges in clothing production. One significant issue has been the susceptibility of hydrophilic cotton fabrics, commonly used in healthcare and sportswear, to bacterial growth, posing hygiene concerns. To deal with this, it becomes crucial for us to make durable cotton fabrics that can fight bacteria. This study explores the development of durable antibacterial cotton textiles by utilizing a range of antibacterial agents and mechanisms. Chitosan's properties, such as its ability to inhibit fungal growth, compatibility, non‐toxicity, bioactivity, and antimicrobial potential make it a promising candidate for the textile industry. Additionally, the incorporation of metal nanoparticles along with chitosan offers interesting potential, such as UV absorption, self‐cleaning capabilities, and antimicrobial activity. Therefore, research aimed at enhancing cotton fabric by harnessing the potential of chitosan and metal nanoparticles continues to attract significant attention in today's textile world. Cotton fabric modified by combining chitosan and nanoparticles exhibits high antimicrobial activity compared to fabric modified with either nanoparticles or chitosan alone. The implications of this study are far‐reaching with improvement in hygiene, comfort, and durability in a wide range of clothing applications, thus making a substantial contribution to the evolution of the textile industry.

Incorporating metal nanoparticles in porous materials via selective heating effect using microwave

Incorporating metal nanoparticles in porous materials via selective heating effect using microwave

Paper-Derived Carbon Electrodes, a Versatile Option to Develop Electrochemical Sensors

Carbon-based materials are particularly well-suited for electroanalytical applications due to their distinct properties, such as high chemical stability, large electroactive areas, wide electrochemical potential window in aqueous solutions, low electrical resistance, rich surface chemistry, and activity towards a variety of redox reactions. While carbon electrodes can be produced via thermal decomposition of gaseous hydrocarbons followed by their surface-induced recombination, this method is not cost-effective and suffers from both low efficiency (~20%) and limited selectivity towards graphitic forms. Alternatively, carbon electrodes can be developed via pyrolytic treatment of non-volatile substrates. This approach yields carbon materials that are rich in graphitic phases and provides researchers a much richer selection of starting materials and source-to-product efficiencies ~70%. Our team has applied this approach to develop several optically transparent carbon electrodes and has described a method for fabricating carbon electrodes by pyrolysis of paper, using a tube furnace and under a mild reducing atmosphere. The resulting electrodes not only feature the properties of traditional carbon materials but also preserve the 3D structure of the starting material, are mildly hydrophobic, and offer a wide electrochemical window and can be patterned using laser engraving. Moreover, the process also enables the incorporation of metallic nanoparticles within the structure of the material (by pyrolyzing paper pre-soaked in a solution containing the selected cation), significantly improving the conductivity of the material. Thus, this presentation will provide a brief summary of the reactions leading to the fabrication of these substrates as well as discuss the most recent applications towards their use as sensors in microfluidic devices.Special emphasis will be placed on the use of these electrodes for the detection of S. aureus, application that required the modification of the material with a thin layer of sputtered gold (that minimizes lateral resistivity and significantly improves the electron transfer process) and with chitosan (used as a binder to offer flexibility). This biosensor was controlled using a custom-built potentiostat (via a wireless connection), which was used to detect the presence of the bacteria via the oxidation of the ferrocyanide (produced by the bacteria’s respiration cycle) in the presence of mannitol.More information about the group can be found in our web site scienceweb.clemson.edu/uacl/

Immobilizing Metal Nanoparticles on Hierarchically Porous Organic Cages with Size Control for Enhanced Catalysis

Incorporating metal nanoparticles (MNPs) into porous composites with controlled size and spatial distributions is beneficial for a broad range of applications, but it remains a synthetic challenge. Here, we present a method to immobilize a series of highly dispersed MNPs (Pd, Ir, Pt, Rh, and Ru) with controlled size (<2 nm) on hierarchically micro- and mesoporous organic cage supports. Specifically, the metal-ionic surfactant complexes serve as both metal precursors and mesopore-forming agents during self-assembly with a microporous imine cage CC3, resulting in a uniform distribution of metal precursors across the resultant supports. The functional heads on the ionic surfactants as binding sites, together with the nanoconfinement of pores, guide the nucleation and growth of MNPs and prevent their agglomeration after chemical reduction. Moreover, the as-synthesized Pd NPs exhibit remarkable activity and selectivity in the tandem reaction due to the advantages of ultrasmall particle size and improved mass diffusion facilitated by the hierarchical pores.

Thermally‐controlled spherical peptide gel architectures prepared using the pH switch method

AbstractSelf‐assembling nanostructured peptide gels are promising materials for sensing, drug delivery, and energy harvesting. Of particular interest are short diphenylalanine (FF) peptides modified with 9‐fluorenylmethyloxycarbonyl (Fmoc), which promotes the association of the peptide building blocks. Fmoc‐FF gels generally form fibrous networks and while other structures have been demonstrated, further control of the gelation and resulting ordered three‐dimensional structures potentially offers new possibilities in tissue engineering, sensing, and drug release applications. Herein, we report that the structure tunability of Fmoc‐FF gels can be achieved by controlling the water content and the temperature. We further explore the incorporation of metal nanoparticles in the formation of the gel to enable optical sensing applications based on hybrid Fmoc‐FF‐nanoparticle microspheres. Finally, fluorescence lifetime imaging microscopy reveals a correlation between lifetime and reduced bandgap, in support of a semiconductor‐induced charge transfer mechanism that might also increase the stability of an excited state of a probe molecule. The observations potentially further widen the use of these peptide materials in bioimaging and sensing applications.

Highly active and stable catalysts for Baeyer–Villiger oxidation – Traditional postloading vs in situ synthesis of Fe/N/C nanoparticles

Nitrogen-doped carbon composites are prepared using simple precursors, such as glucose or urea and used as supports for Fe nanoparticles. The present work investigated two approaches for incorporating metal nanoparticles into the composite: traditional metal postloading and in situ formation of a metal/N-doped carbon catalyst. The impacts of the preparation technique on (i) the characteristics of the resulting iron oxides (Fe2O3 and Fe3O4) and (ii) the nanoparticle distribution on the support were determined. Microscopic surface characterization revealed that the postloading method promoted a uniform distribution of Fe nanoparticles (5–10 nm), which enhanced the activity and long-term stability of the catalytic system for the Baeyer–Villiger oxidation of cyclic ketones. The product yield reached 97% (5 h, 60 °C), and after the third reaction cycle, the yield remained at 96%. The proposed synthetic approach for preparing active and stable catalysts provides a new perspective for the inexpensive and sustainable synthesis of lactones.

Laser induced breakdown spectroscopy of aluminum incorporated with metallic nanoparticles

Laser-Induced Breakdown Spectroscopy is a promising spectroscopic technique with a vast spectrum of applications in fields concerned with identification and detection of elements. But it faces some limitations due to self-absorption, noise due to matrix effect and line broadening resulting in low emission signal. This research proposes LIBS signal enhancement by incorporation of metal nanoparticles (Cu, Mg, Au) on Al surface and compares their effect. The successful optical emissions enhancement is achieved as the emission intensities of Al- and Na- lines of three coated samples are compared with those of uncoated Al. The Electron Temperature has been evaluated by Boltzmann plot and an increase in Electron Temperature has been observed with the incorporation of nanoparticles to the aluminum surface as compared to the untreated aluminum, due to more plasma emissions. The Electron Number Density of the aluminum plasma did not have much effect with the incorporation of Nanoparticles. The Local Thermal Equilibrium condition has been satisfied and checked by Mc Whirter’s Criterion. The incorporation of metal nanoparticles can be declared as an effective method not only for LIBS signal enhancement but also better detection of trace elements which were not observed without the use of Nanoparticles.

The effects of metal nanoparticles incorporation on the mechanical properties of denture base acrylic resin.

The aim of this study was to examine the flexural strength of acrylic resin base material incorporated with iron, copper, and titanium nanoparticles. Seventy bars of samples (65x10x2.5 mm3) were divided into seven groups. Acrylic samples were prepared according to the manufacturer's instructions. Fe2O3, CuO and TiO2 nanoparticles were manually added in a proportion of 1wt% and 3wt% to the heat-polymerized acrylic resin. The Universal Testing Machine was used for 3-point flexural test of 5 mm/min force. ANOVA and Weibull analyses were used for the statistical analyses. A statistical difference was found between the nanoparticle-added group and the control group. The highest mean value was observed for the 1wt% TiO2 added group, (84.99 MPa) and the lowest value was for the 3wt% CuO added group (71.32 MPa) (p<0,001). The 3wt% Fe2O3 and CuO added groups showed lower values than the control group. The incorporation of TiO2 nanoparticles into acrylic resin in a proportion of 1wt% increased the flexural strength values of the resins. Within the limitations, the nanoparticle addition to acrylic resins could improve the mechanical properties; however, when the percentage of nanoparticle addition increases, the flexural strength values of the acrylic resins decrease.

(Keynote) Mechanistic Understanding of the Activity of Atomically Dispersed Transition Metal-Nitrogen-Carbon Catalysts in Oxygen, Carbon Dioxide or Nitrogen Electro-Reduction

Over the last two decades, platinum group metal-free (PGM-free) catalysts are attracting increasing attention and finding applications in several important process across many electrochemical energy technologies. Among those PGM-free materials, atomically dispersed (AD) transition metal-nitrogen-carbon (M-N-C) catalysts are gaining exceptional popularity as they demonstrate very high (for this class of materials) activity in oxygen reduction reaction (ORR)1 and are the only cathode catalysts suitable for both proton exchange membrane fuel cells (PEMFC) and alkaline, including anion/hydroxyl exchange membrane fuel cells (AFC, AEMFC/HEMFC). Over the last few years, M-N-C catalysts have shown promising activity in carbon dioxide reduction reaction (CO2RR).2 In this case, varying the transition metal in M-N-Cs opens routes for controlling the selectivity towards a list of C1 and C2 products. There are recent reports on catalytic activity of AD M-N-C materials in direct electro-reduction of molecular nitrogen (N2RR) or reactions of reduction of nitrates, nitrites or various nitrogen oxides (NOx). We have systematically investigated all these processes having as a base the M-N-C catalysts synthesized by sacrificial support method (SSM) – a hard template approach with transition metal salt and charge-transfer organic salt (nicarbazin) mixed by ball-milling, pyrolyzed at high temperature in inert atmosphere and then etched in HF after cooling. In most cases a secondary (similar) pyrolysis was performed to refine the material and ensure its AD character.The makeup and structure of the active site/sites of the AD M-N0C electrocatalysts, including geometry (coordination) and chemistry (composition and oxidation state) remain contentious to this day. There is an emerging agreement however, that the transition metal (at least for the 2nd row transitions meals) is immediately associated with (liganded by) the nitrogen functionalities, displayed on the surface if the carbonaceous substrate. It is almost universally accepted that N-coordinated AD transition metal ions, either as in-plane or edge-type defect in “graphene” sheet, are the main/principal active sites. This is often combined with a broadly accepted hypothesis that micro-porous surface area plays a critical role forming edge-type, intercalational active sites while meso-porous interface is most-likely associated with the in-plane, substitutional AD metal sites. Candidate structures participating in reativity towards O2, CO2 or nitrogen species include a list of nitrogen-containg and oxygen-containng moeties in the carbonaceous matrix. The carbon itself displays various degrees of graphitization, depending on the transition metal used in M-N-C synthesis. Additional complexity in this calss of caralysts study comes from the fact that many samples are not strictly AD materials. They often contain incorporated metal nano-particles, corresponding (native) oxides and/or carbides and nitrides (oxocabides and oxonitrides have been observed as well).These “unrefined” M-N-C materials are often used in practice and the corresponding nano-particle components of the de-facto nanocomposites do alter substantially the reactivity and selectivity of the catalysts in all these electro-reduction reactions.This talk discusses the mechanistic aspects of M-N-C catalysts in ORR, CO2RR, N2RR and electroreduction of nitrogen-containing oxo-species, obtained when cross-referencing electrochemical activity results obtained in rotating disk and rotating ring-disk electrodes setting (RDE/RRDE) with those observed in near-ambient pressure X-ray photo-electron spectroscopy (NAP-XPS) and supported by density functional theory calculations of the reagents adsorption on AD transition metal or nitrogen- or oxygen-containing moieties from the carbonaceous matrix of the M-N-Cs. The later are of particular importance as significant reactivity has been observed for most of those processes when metal-free, nitrogen-doped carbon (N-C) catalysts are used.3 We will present a case that outlines the reactivity of M-N-C in those important electro-reduction reactions in terms of (i) role of the AD transition metal, (ii) role of the surface N-groups as co-catalysts/alternative sites (iii) role of surface oxides as co-catalysts or hydrophilic/hydrophobic properties descriptor, the last being also critically dependent on morphology.4

Optimization of metal nanoparticles concentration in dye solution to enhance performance of dye sensitized solar cells

In this study, we incorporate metal nanoparticles of AuNP and AgNP into dye N-719 solution in order to enhance the light absorption of dye-sensitized solar cells (DSSCs) device. AuNP or AgNP was mixed into N-719 dye solution by optimized the concentration of metal NPs. The optical property of the mixtures was investigated by use of UV-Vis spectroscopy while the morphology of the solutions was captured by TEM microscopy. The performance of DSSCs was done by J-V measurement equipped with solar simulator under light illumination of 100mW/cm2. Our fabricated DSSC devices show the enhancement of current density and power conversion efficiency (PCE) with the incorporation of metal NPs into dye layer. Addition of gold nanoparticle capped by dodecanethiols (AuDT) 5.66 wt.% reveals the enhancement of PCE devices from 1.58% without AuDT as reference to 2.77% with AuDT. Similar case for the addition of AgSC8 into dye of DSSC gives the same tendencies.