Nanostructured Architectures Research Articles

(Invited) The Role of Surface Inhibition in Deterministic Controlled Electrodeposition

Templated electrodeposition is a common practice for the fabrication of metal nanostructures. The nanostructure architecture is set by that of the nanoporous template. For complex nano-architectures such as the metal nanomesh (see Figure) which was developed in our group [1,2], templates will remain necessary. Nonetheless, the 3D nanoporous anodized aluminum oxide (AAO) used for the templated electrodeposition, did form by self-assembly. Regular AAO made from pure Al has only vertical pores with a hexagonal arrangement. The additional horizontal pores in the 3D-AAO are formed with regular interval by doping of the aluminum with Cu [1]. Such level of deterministic control on the growth direction is not yet achievable with electrodeposition. Yet, directed growth of pillars and nanowires has been achieved by control of current inhibiting surface layers, either introduced by additives [3] or intrinsic to the metal electrochemistry [4]. We will shortly discuss the example of indium electrodeposition where InCl intermediate adsorbate is believed to form a coating around electrodeposited indium, leading to large single crystalline morphologies and nanowires when guided by a shallow pattern [3].Conformal deposition of thin-film coatings on high aspect ratio structures is typically claimed by Atomic and Molecular Layer Deposition (ALD and MLD). The nature of the surface limited reactions of these vapor-phase methods allows for the formation of continuous sub-nanometer to a few tens of nanometer thin films with uniform thickness over the most complex architectures. The accuracy of the technique goes at the cost of long deposition cycles especially when very large surface areas with extreme aspect ratios (>100) are involved. In recent years, electrodeposition processes have shown where the metal electrodeposition reaction for e.g. Ni or Pt can be inhibited early on, similarly leading to sub-nanometer to few nanometer thick coatings by cycling [5, 6]. In this paper, we will show examples where this process can be used also to coat nano-architectures such as our nanomesh with very large surface area (100 cm2 per planar cm2) and aspect ratio (100x).Finally, the electrochemical fabrication of oxide thin-films by electro-precipitation and electrochemically induced sol-gel reactions will be discussed. The poor electronic conductivity of oxides makes that the reaction is maintained by ionic conduction through the films, similar as for oxide formation by anodization. The resistive nature of the layers typically allows also for good conformality over high aspect ratio substrates [7]. Similarly, thin polymer films such as poly-phenylene oxide or PPO can be made conformally [8].[1] "The Formation Mechanism of 3D Porous Anodized Aluminum Oxide Templates from an Aluminum Film with Copper Impurities" Johannes Vanpaemel, Alaa Abd-Elnaiem, Stefan De Gendt, Philippe M. Vereecken, J. Phys. Chem. C, 119 (4), 2105–2112 (2015); [2] “Combining High Porosity with High Surface Area in Flexible Interconnected Nanowire Meshes for Hydrogen Generation and Beyond" Stanislaw Zankowski and Philippe M. Vereecken, ACS Appl. Mater. Interfaces, 10 (51), pp 44634–44644 (2018); [3] “Electrodeposited free-standing single-crystal indium nanowires" G. Hautier, J. D’Haen, K. Maex and P.M. Vereecken, ESL 11, K49 (2008); [4] “Fabrication of complex architectures using electrodeposition into patterned self-assembled monolayers” N.S.Pesika, A. Radisic, K.J. Stebe, P.C. Searson, Nano Letters. 6, 1023-1026 (2006); [5] Electro-chemical deposition of sub-nanometer Ni films on TiN” Johannes Vanpaemel, Masahito Sugiura ,Daniel Cuypers, Marleen H. van der Veen, Stefan De Gendt, Stefan and Philippe M. Vereecken, Langmuir, 30 (8), 2047–2053 (2014); [6] “Self-Terminating Growth of Platinum Films by Electrochemical Deposition” Yihua Liu, Dincer Gokcen, Dincer Gokcen, Ugo Bertocci, Tom Moffat, Science 338(6112):1327-30 (2012); [7] "Electrodeposition of Adherent Submicron to Micron Thick Manganese Dioxide Films with Optimized Current Collector Interface for 3D Li-Ion Electrodes" Marina Timmermans, Nouha Labyedh, Felix Mattelaer, Stanislaw Zankowski, Stella Deheryan, Christophe Detavernier, and Philippe M. Vereecken, J. Electrochem. Soc. 164 , 14, D954-D963 (2017); [8] “Self-limiting electropolymerisation of ultrathin, pinhole free poly(phenylene oxide) film on Carbon Nanosheets” S. Deheryan, D. J. Cott, R. Muller, M. Heyns and P. M. Vereecken, Carbon, , 88, 42-50, (2015). Figure 1

Hierarchical nanostructured surface design for robust and flexible multifunctional devices

This paper investigates structural and functional properties of a hierarchical hybrid flexible material with nanostructured surface architecture. These solids comprise of carpet-like arrays of covalently bonded carbon nanotubes (CNT) on the surface of strong and flexible carbon fabric. In-depth analysis of the multi-scale morphology of this structure is provided, with emphasis on structure-property relationships relevant to surface-interaction related applications such as catalysis, sensing, microfluidics and bio-scaffolding devices. A two-step process is used to anchor carbon nanotubes directly on the surface of carbon fiber cloth, and its morphology, structure and surface chemistry analyzed in detail. Surface structure model from structural and physical property measurements predict over 2000 times increase in specific surface area (SSA) of the fabric due to CNT carpet growth. This estimate is in good agreement with direct SSA measurement using Brunauer–Emmett–Teller (BET) gas-adsorption technique, indicating full utilization of the CNT surface sites, which can be used for adsorption, functionalization, thermal or electrical transport. Electrical measurement of these materials shows a systematic increase of sheet conductivity of the fabric with increasing CNT carpet height. These results indicate that this type of material design can combine the structural durability and flexibility of advanced fabrics with the enhanced surface activity of nanomaterials for a wide variety of surface interaction devices of the future.

Microwave assisted synthesis of core-shell Ni-Co/graphene nano sheets and their catalytic activity for methanol electro-oxidation

The improvement of nanostructured architectures the use of less expensive first–row transition metals with high electrocatalytic activity to substitute noble-metal-based electrocatalysts has currently received enormous interest in the discipline of easy and sustainable energy generation technology. Nickel-Cobalt core–shell nanostructures for supported over N-doped graphene nanosheets (Ni@Co/N-GNS) present higher catalytic activity due to presence of increased surface active centers, high surface area and extended reactive zones. Using microwave irradiation, bimetallic Ni@Co nanoparticles are deposited on N-Doped graphene nanosheets. Influence of reactive conditions and composition of metal precursors are studied systematically, these studies revealed that core–shell nanostructures synthesized using 1:1 metal precursors irradiated under microwave for 40 s displayed superior electro catalytic activity towards methanol. XPS, SEM, and EDAX studies are performed to understand physico-chemical properties of Ni@Co/GNS catalyst. It is deduced that thickness, surface characteristics and catalytic properties of Ni@Co deposits could be influenced pointedly by microwave conditions. Core-shell morphology is decidedly of assistance to offer readily accessible active Ni@Co active zones for methanol oxidation reaction, which is evidenced by cyclic voltammetry, Impedance analysis and chronoammperometric studies. The developed catalyst is a therefore a potential electrocatalyst for direct alcohol fuel cells.

Nanoengineering InP Quantum Dot-Based Photoactive Biointerfaces for Optical Control of Neurons.

Light-activated biointerfaces provide a non-genetic route for effective control of neural activity. InP quantum dots (QDs) have a high potential for such biomedical applications due to their uniquely tunable electronic properties, photostability, toxic-heavy-metal-free content, heterostructuring, and solution-processing ability. However, the effect of QD nanostructure and biointerface architecture on the photoelectrical cellular interfacing remained unexplored. Here, we unravel the control of the photoelectrical response of InP QD-based biointerfaces via nanoengineering from QD to device-level. At QD level, thin ZnS shell growth (∼0.65 nm) enhances the current level of biointerfaces over an order of magnitude with respect to only InP core QDs. At device-level, band alignment engineering allows for the bidirectional photoelectrochemical current generation, which enables light-induced temporally precise and rapidly reversible action potential generation and hyperpolarization on primary hippocampal neurons. Our findings show that nanoengineering QD-based biointerfaces hold great promise for next-generation neurostimulation devices.

Morphology control of copper hydroxide based nanostructures in liquid phase synthesis

Synthesis and study of copper hydroxide based nanostructures is of continued interest for researchers as these materials act as templates for formation of CuO and because of their individual applications for energy storage and sensing. However, the synthesis mechanisms and the intrinsic properties of these nanostructures are rarely investigated. In this work, we show the template-free bottom-up synthesis and shape control of copper hydroxide based nanostructures grown in liquid phase, from 1D nanowires to 2D layered nanoplatelets and 3D nanocrystals. Precise control over the pH of the solution and the reaction temperature lead to intended tuning of the morphology and chemical composition of the nanostructures. Among the copper hydroxy salts, the botallackite polymorph is known as an intermediate compound which is difficult to stabilise in mother solution. We show here a way to achieve the stable botallackite in form of nanoplatelets. The obtained copper hydroxide based nanostructures are analysed using X-ray Diffraction, X-ray Photoelectron Spectroscopy and absorbance spectra. We contemplate upon the rationale behind this change in shape and material. Having an improved understanding of the formation mechanism of the various nanostructures will enable researchers to have better control over synthesis with designed architecture of nanostructures for targeted applications.

Spongy nano surface architecture of chemically grown BiVO4: High-capacitance retentive electrochemical supercapacitor

Design of nanostructured surface architecture is currently playing a vital role to enhance the energy storage capability of electrode materials and opening up a new era for future technologies through electrochemical supercapacitors. Present effort portrays the growth of nanostructured bismuth vanadate (BiVO4) as an active electrode for supercapacitor application by using ease and industry scalable successive ionic layer adsorption and reaction (SILAR) method. Structural analysis reveals the development of orthorhombic structured BiVO4 with spongy nano-pebbles like surface architecture. Synthesized BiVO4 electrode yields remarkable capacitance of 707 F/g @3 mV/s scan rate. Faradaic and capacitive type contributions have been evaluated for in-depth understanding along with the estimation of electrochemical active surface area. Electrochemical impedance spectroscopy (EIS) analysis of BiVO4 electrode exhibits 5.723 and 0.89 Ω cm2 values of series and charge transfer resistances, respectively. Interestingly, BiVO4 electrode delivers outstanding capacitive retention of 102% even at 3500 cycles, indicating its potential candidature for the advancement in high capability supercapacitors with excellent stability for the future technologies.

Hydrothermal architecture of Cu5V2O10 nanostructures as new electro-sensing catalysts for voltammetric quantification of mefenamic acid in pharmaceuticals and biological samples

A novel nano-electrocatalyst based on Cu5V2O10 is successfully fabricated by one-pot hydrothermal treatment and used for the examination of mefenamic acid (MFA) in real samples, for the first time. Controlling the combined factors of complexing agent's (4, 4′-Diaminodiphenylmethane, DDM) molar ratio, hydrothermal temperature, and reaction time is responsible for providing the optimal structural and morphological changes of the crystals. The effect of operating conditions of Cu5V2O10 nanostructures is investigated using FT-IR, XRD, and EDX as structural and elemental analyses. Also, other properties such as particle size and morphological studies were accomplished by FE-SEM, and HR-TEM. The results reveal that the monoclinic phase of Cu5V2O10 with particle size of 34 nm is the outcome of hydrothermal treatment of 200 °C for 18 h, which DDM template with molar ratio of 2.0 M serves as phase stabilizing matrix. Herein, it is demonstrated the electrochemical biosensing characteristics of the nano-scale Cu5V2O10 modified carbon paste electrode (CV/CPE) by voltammetry techniques. The drug sensing capabilities of the boosted CV/CPE platform exhibit linear dynamic range of 0.01–470 μM, and low detection limit of 2.34 nM with excellent sensitivity and selectivity. The appropriate electrical conductivity and layered structure of the compound causes a valuable platform for minimally invasive assessment of MFA in biological and pharmaceutical media with recovery rate of 98.3%–110.0% and 93.6%–106.7%, respectively. As a result, the proposed nanostructures as great candidate offer excellent electrocatalytic activity in biomedicine applications.

The synthesis and SERS study of gold-palladium asymmetric nanostructures

<p indent="0mm">Gold-palladium two-component nanostructures have attracted extensive attentions due to their synergetic coupling between optical and catalytic properties, and have shown important application potential in solar energy conversion and storage, photoelectric catalysis, photoelectric devices, biological imaging, medical diagnosis and treatment and other fields. However, the synthesis of gold-palladium nanomaterials with synergistic properties still face great challenges. The reason is that the palladium can epitaxially overgrow on the Au seed surface due to the lattice match. It means that the growth of palladium on Au seeds often leads to symmetric core-shell gold-palladium structures (Au@Pd). The Pd shell can greatly prevent the plasmonics of Au core by blocking light and deteriorating the surface plasmon resonance performance through the interface damping. One strategy is to grow ultrathin Pd shell (with thickness smaller than <sc>5 nm)</sc> to realize the synergistic coupling between plasmonics and catalysis. The other more challenging way is to break the structural symmetry to prepare Janus-type gold-palladium asymmetric nanostructures. The asymmetric spatial arrangement of the two components within one nanoparticle will significantly improve the synergistic coupling effect. In this study, two methods for preparation of gold-palladium nanostructures in solution and on solid surface respectively were developed. The concave cuboid and dumbbell-shaped nanostructures with asymmetric palladium distribution on Au nanorods were prepared by adjusting the concentration of copper ions in the Au-nanorod seed solution for the first time. It was demonstrated that copper ions can compete with CTAB to adsorb on the surface of Au nanorods, which can regulate the interfacial energy of palladium deposition on the surface of Au nanorods. Therefore, the changing of gold-palladium interfacial energy caused the growth mode to be gradually transformed from the epitaxial growth to discontinuous patch on the seed surface, leading to the generation of an array of gold-palladium asymmetric nanostructures, including gold-palladium concave cuboidal nanoparticles and dumbbell-shaped nanoparticles, where palladium was mainly grown on the two ends of Au nanorods. Besides the solution-mediated synthesis, we also developed substrate-based techniques combined colloidal chemistry to prepare gold-palladium nanostructures. This method combined the merits of substrate-based self-assembly techniques and powerful colloidal chemistry to prepare a rich class of nanostructure architectures with unique properties. The monolayer of Au-octahedron was prepared at an air-solid interface and then transfer to a silicon surface. The substrate-immobilized self-assembly monolayer was used as seeds to induce the growth of palladium by dipping into the growth solution. A series of gold-palladium nanostructures with different palladium loadings were prepared on the solid surface with a monolayer of Au-octahedron as seeds by controlling the palladium content in the growing solution. Because of the steric hindrance effect of solid surface, palladium is preferred to nucleate on the surface of Au octahedron away from solid base. Therefore, the fabricated gold-palladium nanostructures have asymmetric spatial distribution of the gold and palladium components as was demonstrated by SEM and XRD analysis. Through the study of the SERS performance of the gold-palladium nanostructures under different palladium loadings, the surface-supported gold-palladium nanostructures with optimal SERS performance was obtained. The catalytic hydrogenation of p-nitrothiophenol into p-aminothiophenol through the optimal gold-palladium asymmetric nanostructure was monitored by <italic>in</italic>-<italic>situ</italic> SERS. The experimental results showed that the asymmetric palladium nanostructures prepared in this study realized the synergistic coupling between catalytic and SERS properties. It is expected that the method to synthesize asymmetric nanostructure developed here will play an important role in the field of heterogeneous catalysis.

Development of nickel based cermet anode materials in solid oxide fuel cells – Now and future

High temperature solid oxide fuel cell (SOFC) is the most efficient and clean energy conversion technology to electrochemically convert the chemical energy of fuels such as hydrogen, natural gas and hydrocarbons to electricity, and also the most viable alternative to the traditional thermal power plants. However, the power output of a SOFC critically depends on the characteristics and performance of its key components: anode, electrolyte and cathode. Due to the highly reducing environment and strict requirements in electrical conductivity and catalytic activity, there are limited choices in the anode materials of SOFCs, particularly for operation in the intermediate temperature range of 500–800 ​°C. Among them, Ni-based cermets are the most common and popular anode materials of SOFCs. The objective of this paper is to review the development of Ni-based anode materials in SOFC from the viewpoints of materials microstructure, performance and industrial scalability associated with the fabrication and optimization processes. The latest advancement in nano-structure architecture, contaminant tolerance and interface optimization of Ni-based cermet anodes is presented. And at the end of this paper, we propose and appeal for the collaborative work of scientists from different disciplines that enable the inter-fusion research of fabrication, microanalysis and modelling, aiming at the challenges in the development of Ni-based cermet anodes for commercially viable intermediate temperature SOFC or IT-SOFC technologies.

Synergetic Enhancement of Thermoelectric Performance by Selective Charge Anderson Transition and Topological Phase Transition

Considerable efforts have been devoted to enhancing thermoelectric (TE) performance, by employing phonon scattering from nano-structural architecture, and material design using phonon-glass and electron-crystal concepts.

Free‐Standing Nanostructured Architecture as a Promising Platform for High‐Performance Lithium–Sulfur Batteries

Lithium–sulfur (Li–S) batteries have attracted intensive attention due to their high energy density and low cost. However, Li–S batteries are still confronted with the challenges of low sulfur utilization, short cycle life, and unsatisfactory Coulombic efficiency. Free‐standing nanostructured architectures often have tunable features, such as strong mechanical properties, high electrical conductivity, and abundant porous structures, endowing them with the ability to serve as sulfur hosts, functional interlayers on separators, as well as lithium matrices. Herein, the electrochemical principles of Li–S batteries and the motivation for designing free‐standing architectures for sulfur cathodes, functional separators, and lithium anode protection are described. Furthermore, the recent progress on free‐standing sulfur cathodes based on carbon nanotubes, graphene, and MXenes is summarized in detail. In addition, the design of free‐standing nanostructured architectures in functional separators and lithium anode protection is also presented. Finally, future developments and prospects in the design of free‐standing architectures for Li–S batteries are discussed.

Gold Spherical and Flake Assemblies Fabrication Through Calcination of Gold Nanoparticles Incorporated Poly(acrylonitrile) Nanofibers

This work reports on the outcome of the calcination of gold nanoparticles incorporated polyacrylonitrile nanofibers in air which results in the formation of gold spherical and flake cluster assemblies. The architecture and morphology of gold nanostructures play a role in determining their different applications. The results of this research showed that calcination at 650 °C for 5 h led to almost complete disintegration and disappearance of the poly(acrylonitrile) matrix and polyhedral nanostructures were formed. FTIR analysis showed the complete disappearance of poly(acrylonitrile) matrix at calcination temperatures of 850 °C and 1000 °C. XRD analysis also showed the complete disappearance of poly(acrylonitrile) at calcination temperatures above 850 °C. SEM micrographs taken after calcination of the precursor showed that calcination around 850 °C leads to the formation of spherical gold clusters, whereas, calcination at 1000 °C produces gold flake clusters.

Multifunctional sensing platform based on green-synthesized silver nanostructure and microcrack architecture

Multimodality in simultaneous sensing of multiple stimuli is highly desirable for artificial skins to expand their applications in industrial robotics, e.g., environmental monitoring robots. However, integrating multifunctional sensing abilities into a single material system via a green-synthesized method is a considerable challenge. In this study, we developed a facile method to fabricate a multifunctional platform with a high-level of performance, simultaneously in pollutant-, strain-, and humidity- monitoring, based on a cellulose nanocrystal (CNC)-templated silver nanostructure and microcrack architecture design. The green-synthesized CNC-regulated silver nanostructure endows the sensing platform with a high sensitivity (10−15 M) for the detection of organic dyes in wastewater. Furthermore, inspired by the sensing mechanism and versatility of a spider’s crack‐shaped slit organs, a unique microcrack architecture was constructed on an elastomer to sense strain and humidity. This work is expected to not only guide the design of material‐based approaches for multifunctional sensing, but also provides new insights for building environment-monitoring robots in practical applications.

Temperature driven high-performance pseudocapacitor of carbon nano-onions supported urchin like structures of α-MnO2 nanorods

The promising pseudocapacitive charge storage insists the strategic design of three-dimensional architecture of nanostructures with extra-active redox sites on and/or near surface with high capacity of ionic insertion into the porous network of electrodes. Herein, we report the urchin like structure of α-MnO2 nanorods grown on carbon nano-onion (CNO) support via simple, cost-effective wet chemical method. The highly crystalline α-MnO2 nanorods with larger spinel sizes of 0.46 nm and 0.18 nm are characterized by SEM, TEM, XRD and Raman spectra. These spinel structures of α-MnO2 nanorods offers large cavity for ions insertion, which further improved by increasing temperature due to fast ionic mobility. The temperature driven increment of specific capacity from 202 Cg-1 to 363 Cg-1 at current density 0.3 Ag-1 is accomplished owing to the improved ionic conductivity, surface area and fast charge transfer. Further the 78% capacitance retention after 1000 cycles at 70 °C is realized, which is just 17% lower that the cyclic stability at 4 °C. It emphasizes an importance of three-dimensional design/architecture of electrode materials for the high-temperature pseudocapacitor applications.

Hybrid Porous Silicon Biosensors Using Plasmonic and Fluorescent Nanomaterials: A Mini Review.

During the last two decades, porous silicon (PSi) has been proposed as a high-performance biosensing platform due to its biocompatibility, surface tailorability, and reproducibility. This review focuses on the recent developments and progress in the area related to hybrid PSi biosensors using plasmonic metal nanoparticles (MNPs), fluorescent quantum dots (QDs), or a combination of both MNPs and QDs for creating hybrid nanostructured architectures for ultrasensitive detection of biomolecules. The review discusses the mechanisms of sensitivity enhancement based on Localized Surface Plasmon Resonance (LSPR) of MNPs, Fluorescence Resonance Energy Transfer (FRET) in the case of MNPs/QDs donor-acceptor interactions, and photoluminescence/fluorescence enhancement resulting from the embedded fluorescent QDs inside the PSi microcavity. The review highlights the key features of hybrid PSi/MNPs/QDs biosensors for dual-mode detection applications.

Micrometer-sized ferrosilicon composites wrapped with multi-layered carbon nanosheets as industrialized anodes for high energy lithium-ion batteries

Various nanostructured architectures have been demonstrated to be effective to address the issues of high capacity Si anodes. However, the scale-up of these nano-Si materials is still a critical obstacle for commercialization. Herein, we use industrial ferrosilicon as low-cost Si source and introduce a facile and scalable method to fabricate a micrometer-sized ferrosilicon/C composite anode, in which ferrosilicon microparticles are wrapped with multi-layered carbon nanosheets. The multi-layered carbon nanosheets could effectively buffer the volume variation of Si as well as create an abundant and reliable conductivity framework, ensuring fast transport of electrons. As a result, the micrometer-sized ferrosilicon/C anode achieves a stable cycling with 805.9 mAh g −1 over 200 cycles at 500 mA g −1 and a good rate capability of 455.6 mAh g −1 at 10 A g − 1 . Therefore, our approach based on ferrosilicon provides a new opportunity in fabricating cost-effective, pollution-free, and large-scale Si electrode materials for high energy lithium-ion batteries. Ferrosilicon composites wrapped with multi-layered carbon nanosheets (MLC) were fabricated. MLC constructs more abundant and reliable conductive network and provides more effective confinement for micrometer-sized Si than conventional carbon coating, which induces superior electrochemical performance.

Ionic Diffusion, Nanoparticle Formation and Trapping Within Sol‐Gel Made Pillared Planar Nanochannels in a Simple Microfluidic Device

AbstractEfforts to obtain widespread applications in the field of nanofluidics are increasing in intensity in recent years. However, high cost production of nanofluidic devices through the commonly used nanofabrication technologies and the incomplete understanding of solute confinement is still delaying the development of reliable, reproducible and affordable nanofluidic tools. The concentration of species and their diffusion dynamics are strongly influenced by the nanostructure architecture and surface chemistry. Testing a large number of known geometries and surface characteristics has not been possible due to limitations in fabrication procedures. Here, we try to overcome these fabrication difficulties by making the production of large scale nanofluidic devices more viable. We use an alternative bottom‐up method based on supramolecular self‐assembly and sol‐gel chemistry to produce and integrate controlled ceramic nanoporous Pillar Planar Nanochannels (PPN) within microfluidic devices. The system provides a way to easily analyze the diffusion and reaction of species in the aforementioned nanochannels. We show how to extract the nano‐confined concentration and diffusion speed without requiring any expensive analysis instrument. Subsequently, large data sets can be obtained due to the affordability of the presented nanostructure and the ease of its analysis. Moreover, since PPNs have a periodical and regular geometry the obtained data can be compared with simulations, allowing for a better description of the nanoconfined behavior of species.

Pd modified Ni nanowire as an efficient electro-catalyst for alcohol oxidation reaction

Developing highly efficient and economically viable electro-catalyst is very crucial research topic nowadays for achieving affordable direct alcohol fuel cells. Nano-structural architecture plays a crucial role in the catalytic activity. Herein we are reporting, a cost effective one-dimensional (1D) nano structured electro-catalyst for improved methanol oxidation reaction. Pd modified Ni nanowire catalyst towards methanol electro oxidation were prepared by a simple galvanic replacement reaction. Exclusive nano-wire morphology achieved through a wet chemical reduction method without employing any capping agents or surfactants. Pd modified Ni nano-wires exhibited a supreme catalytic activity and durability towards methanol electro-oxidation. The distinctive 1D morphology and strong metal support interaction (SMSI) between Pd and NiO along with the bifunctional effects of Pd and Ni attributed to the enhanced catalytic activity. The amount of precious Pd metal was reduced by 90 wt% with enhanced catalytic efficiency. Ethanol electro-oxidation study showed an improved catalytic activity with mass activity of 1479.79 mA/mg Pd.

Insertion of Iron Decorated Organic-Inorganic Cage-Like Polyhedral Oligomeric Silsesquioxanes between Clay Platelets by Langmuir Schaefer Deposition.

Tuning the architecture of multilayer nanostructures by exploiting the properties of their constituents is a versatile way to develop multifunctional films. Herein, we report a bottom-up approach for the fabrication of highly ordered hybrid films consisting of dimethyldioctadecylammonium (DODA), iron decorated polyhedral oligomeric silsesquioxanes (POSS), and montmorillonite clay platelets. Clay platelets provided the template where Fe/POSS moieties were grafted by the use of the surfactant. Driven by the iron ions present, DODA adopted a staggered arrangement, which is essential to realize the controllable layer-by-layer growth of the film. The elemental composition of the film was studied by X-ray photoelectron spectroscopy and X-ray reflectivity confirmed the existence of smooth interfaces between the different layers.

Electrodeposited ZnO nanoparticles on vertically aligned carbon nanotubes (VACNTs) as promising charge extracting electrodes for halide perovskite devices

This work presents an original nanostructured architecture for energy conversion applications based on vertically aligned carbon nanotubes (VACNTs).