Nickel Oxide Decorated MWCNTs Wrapped Polypyrrole: One Dimensional Ternary Nanocomposites for Enhanced Thermoelectric Performance

Nickel Oxide Decorated MWCNTs Wrapped Polypyrrole: One Dimensional Ternary Nanocomposites for Enhanced Thermoelectric Performance

In-situ generation of nickel oxide nanoparticles (NiO) on functionalized multi-walled carbon nanotubes (MWCNTs-(COOH)3) was successfully achieved, this latter was wrapped with polypyrrole (PPy) nanotubes resulting in a high figure of merit (ZT=1.51×10−2 at RT) compared to PPy alone. This hybrid organic-inorganic nanocomposite material offers the potential for waste heat recovery.


Abstract

This study reports on a customized and revised approach to fabricate “nickel oxide decorated multi-walled carbon nanotubes (MWCNTs) wrapped polypyrrole (PPy)” nanocomposite with enhanced room-temperature thermoelectric (TE) properties. The nanocomposite is formed through three steps: MWCNTs functionalization via diazonium salt grafting of 5-amino-1,2,3-benzene tricarboxylic acid; in situ generation on their surfaces of NiO nanoparticles with a homogenous distribution; the chemical polymerization of pyrrole using methyl orange as templating and dopant to wrap the MWCNTs-(COOH)3-NiO. Various techniques were used as characterization tools, including XRD, TEM, FTIR, Raman, TGA, XPS, and TE measurements. The PPy-MWCNTs-(COOH)3-NiO nanocomposite exhibits significantly higher Seebeck coefficient, electrical conductivity, and power factor than PPy and PPy-MWCNTs-(COOH)3. The achieved enhancement in TE properties (figure of merit, ZTPPy-MWCNTs-(COOH)3-NiO=1.51×10−2) is attributed to the presence of NiO, which acts as a dopant and improves the charge carrier density in the nanocomposite. These results offer the potential for waste heat recovery and large-scale fabrication of high-performance composites.

(B, N)‐Rich B−C−N Nanosheet‐assembled Microwires as Effective Electrocatalysts for Oxygen Reduction Reaction

(B, N)-Rich B−C−N Nanosheet-assembled Microwires as Effective Electrocatalysts for Oxygen Reduction Reaction

B, N-rich BCNNAM (nanosheet-assembled microwires), produced via a conbining growth mechanism of VLS and VS, showed excellent electrocatalytic performances for ORR due to synergistic effect arising from B, C and N as well as hierarchical porous structure.


Abstract

Developing highly active and stable nanocarbon electrocatalysts for the oxygen reduction reaction (ORR) in alkaline medium has attracted much attention due to their potential as an alternative to traditional metal-based or noble metal catalysts. Herein, a unique micro-nano structure of (B, N)-rich B−C−N nanosheet-assembled microwires (BCNNAM) were synthesized and driven electrochemical oxide reduction reaction. The diameter of the microwires about 1 μm, while the nanosheets have an average thickness of less than 20 nm. The compact nanosheets are mostly separated with a bending, curling and crumpling morphology. All those constitutes a ternary system with large surface area and abundant activity sites facilitate fast mass/electron transport for ORR catalytic activity. Thus, the B, N-rich B−C−N nanosheet-assembled microwires show significantly improved electrocatalytic activity with an onset potential of 0.95 V and half-wave potential of 0.83 V compared to BNNAM, nitride-doped carbon, porous carbon and a commercial Pt/C electrocatalyst. Such high catalytic performance of B, N-rich B−C−N micro-nano structures is due to the enhanced activity by the coexistence of B, C and N and the mass transfer promoted by the unique hierarchical porous structure.

Front Cover: Anisotropic Colloidal Particles by Molecular Self‐Assembly: Synthesis and Application (ChemNanoMat 3/2024)

Front Cover: Anisotropic Colloidal Particles by Molecular Self-Assembly: Synthesis and Application (ChemNanoMat 3/2024)

Anisotropic colloidal particles have attracted great attention over the past few decades because of their significant properties that differ from isotropic particles. Molecular self-assembly provides the possibility to design and construct anisotropic colloidal particles from the single-molecule level, and molecular assemblies can both inherit the properties of molecules in single states and integrate the functions of molecules in collective states, which has attracted great interest to researchers. This review article briefly summarizes the research progress of molecules from small molecules, block copolymers and homopolymers to anisotropic particles, including their self-assembly strategies and applications. Finally, the remaining challenges of this topic and future developments in this field have been discussed. More information can be found in the Review by Bing Liu et al.


Size‐Dependent Carbon Dioxide Reduction Activity of Copper Nanoparticle and Nanocluster Electrocatalysts

The electrochemical carbon dioxide (CO2) reduction reaction (CRR, which can convert CO2 into useful compounds at room temperature and ambient pressure by using electricity derived from renewable energy source), has been attracting attention in recent years. This is because it can convert CO2 into useful compounds, which is pertinent to establishing a next-generation recycling-oriented energy society. However, further improvement of the electrocatalyst is required to improve its activity, selectivity, and durability. Among these, copper (Cu) can synthesize various hydrocarbons from CO2 and has been the most studied electrocatalyst for the CRR over many years. In particular, regarding ligand-protected Cu particles for the CRR, the size, shape, and ligands of Cu particles prepared by chemical reduction can be precisely controlled. In this review, we summarize previous research on the size-dependence of the CRR by using Cu particles (nanoparticles and nanoclusters) prepared by liquid-phase reduction, and discuss the current status of these studies for researchers on the electrochemical CRR.

First‐Principles Study of Carbon‐Substituted ZnO Monolayer for Adjusting Lithium Adsorption in Battery Application

First-Principles Study of Carbon-Substituted ZnO Monolayer for Adjusting Lithium Adsorption in Battery Application

We investigate the structural stability, local density of states, bonding information, and charge distribution differences of C-substituted ZnO (C/VZnxOy ) monolayer structures, as well as their interactions with lithium atoms, using the density functional theory (DFT) method. The results indicate that all C/VZnxOy structures are stable. They bind as well as turn Li3 to Li3 + with varying binding strengths.


Abstract

Structural stability, local density of states, bonding information, and charge distribution differences of C-substituted ZnO (C/VZnxOy ) monolayer structures, as well as their interactions with lithium atoms, are investigated using the density functional theory (DFT) method. The energy required to generate vacancies in pristine ZnO monolayers is considerably high, but since the C atoms are strongly adsorbed in the vacant sites, the energy required to form C/VZnxOy structures is reduced. These lattice substitutions cause an alteration of the Zn d-states. The bonding analysis shows that the C−O interaction is stronger than the C−Zn interaction. So, it generates high stability for these structures. Furthermore, because the development of C/VZnxOy is aimed at lithium battery electrode applications, the most fundamental thing that needs to be examined initially is the interaction between the C/VZnxOy surfaces and the lithium atoms. Li3 strongly binds on all C/VZnxOy surfaces, and it turns to Li3 + based on a simple analysis of charge distribution differences. These findings will have a substantial impact on the future development of ZnO monolayers, and their potential as lithium battery electrodes can be studied further.

Colloidal Plasmonic Metasurfaces for the Enhancement of Non‐Linear Optical Processes and Molecular Spectroscopies

Colloidal Plasmonic Metasurfaces for the Enhancement of Non-Linear Optical Processes and Molecular Spectroscopies

Recent developments in colloidal-based plasmonic metasurfaces unlocked new opportunities for the application of these highly dynamic systems to non-linear optical phenomena and molecular spectroscopies. This Minireview summarizes potential advantages and current challenges of colloidal systems for the enhancement of second and third order light-matter interactions and offers a critical perspective on their potential impact on the next generation of photonics metamaterials.


Abstract

Colloidal metasurfaces are emerging as promising candidates for the development of functional chemical metamaterials, combining the undisputed control over crystallography and surface chemistry achieved by synthetic nanochemistry with the scalability and versatility of colloidal self-assembly strategies. In light of recent reports of colloidal plasmonic materials displaying high-performing optical cavities, this Minireview discusses the use of this type of metamaterials in the specific context of non-linear optical phenomena and non-linear molecular spectroscopies. Our attention is focused on the opportunities and advantages that colloidal nanoparticles and self-assembled plasmonic metasurfaces can bring to the table compared to more traditional nanofabrication strategies. Specifically, we believe that future work in this direction will express the full potential of non-linear molecular spectroscopies to explore the chemical space, with a deeper understanding of plasmon-molecule dynamics, plasmon-mediated processes, and surface-enhanced chemistry.

Hexagonal Boron Nitride Spacers for Fluorescence Imaging of Biomolecules

Hexagonal Boron Nitride Spacers for Fluorescence Imaging of Biomolecules

We employ few-layer hexagonal boron nitride (hBN) as a precisely tailorable fluorescence spacer between rhodamine-labelled phosphatidylethanolamine lipid (Rh-PE) membranes and graphene substrates on SiO2/Si substrates. The pre-determined hBN thicknesses can be employed to control the non-radiative energy transfer properties of graphene, with fluorescence quenching following a d −4 distance-dependent behaviour.


Abstract

Fluorescence imaging is an invaluable tool to investigate biomolecular dynamics, mechanics, and interactions in aqueous environments. Two-dimensional materials offer large-area, atomically smooth surfaces for wide-field biomolecule imaging. Despite the success of graphene for on-chip biosensing and biomolecule manipulation, its strong fluorescence-quenching properties pose a challenge for biomolecular investigations that are based on direct optical readouts. Here, we employ few-layer hexagonal boron nitride (hBN) as a precisely tailorable fluorescence spacer between labelled lipid membranes and graphene substrates. By stacking high-quality hBN crystals in the 10–20 nm thickness range on monolayer graphene, we observe distance-dependent fluorescence intensity variations. Remarkably, with hBN spacers as thin as 20 nm, the fluorescence intensity is comparable to bare SiO2/Si substrates, while the intensity was reduced to 60 % and 80 % with ~10 nm and ~16 nm hBN thicknesses respectively. We confirm that pre-determined hBN thicknesses can be employed to control the non-radiative energy transfer properties of graphene, with fluorescence quenching following a d −4 distance-dependent behaviour. This seamless integration of electronically active and dielectric van der Waals materials into vertical heterostructures enables multifunctional platforms addressing the manipulation, localization, and visualization of biomolecules for fundamental biophysics and biosensing applications.

Facile synthesis of carbonized polymer dots and their applications in security inks, sensing, light emitting diodes, and UV shielding films

Carbonized polymer dots (CPDs) have received much attention in recent years owing to their cost-effective synthesis, high resistance to photobleaching, environmental friendliness, and excellent biocompatibility. However, the aggregation-induced fluorescence quenching is a great obstacle to its applications. In this work, the highly fluorescent CPDs are prepared by a facile hydrothermal method assisted by polyethylene glycol (PEG) as the surface passivation agent, where phthalic acid and ethylenediamine are used as carbon and nitrogen source, respectively. Meanwhile, five types of PEG species are applied to prepare five CPDs to investigate PEG on optical properties of the resultant CPDs, among which the best quantum yield reaches 57.0%. The promising applications of CPDs as fluorescent inks, sensors, light emitting diodes, and UV shielding films have been demonstrated. Overall, our contribution here develops a facile and accessible route for the synthesis of CPDs and further demonstrates its versatile applications.

Marigold Like Structure from Methionine Mediated Growth of Positively Charged Gold Nanorod

Marigold Like Structure from Methionine Mediated Growth of Positively Charged Gold Nanorod

Marigold flower like supra structure is fabricated by growth reaction of gold nanorod incubated with methionine with two binding site, which selectively interacts with intermediate Au+ and Au(111) facets during nucleation and growth stage and favors the assembly and merging of nanoparticles. This observation enlightens the role of biomolecules or small molecules behind growth of novel nano-architectures.


Abstract

During morphological evolution of gold nanoparticles, amino acids play a vital role in tuning shape, introducing chirality and inducing facet selective reactivity. Herein, we report the synthesis of unique marigold like structure (MGS) via growth reaction of methionine (Met) incubated positively charged anisotropic gold nanorod (GNR). Varying three important parameters such as growth time, concentration of Met and Au3+ reveals the combination of freshly generated small nucleated particles (fNPs) and GNR towards fabricating the unique MGS containing disk and ray floret parts. Strong interaction between Met and (111) plane of Au0 controls the orientation of (111) plane parallel to the direction of growth. This preferential interaction directs the assembly of gold nanostructures through Au (200) plane and results in merging of fNPs with concave GNR (cGNR) to fabricate the external arrangement of ray floret structure. The structural selectivity is attributed to the electron donating capacity of thioether functional group of Met(S) to Au+, generated prior to secondary nucleation. As confirmed by XPS and ζ-potential analysis, the above interaction controls the Met concentration dependent inhibition of further Au+→Au0 reduction. The growth strategy of GNR has been further validated with a Met enriched peptide to produce disk and ray florets.

Iridium Nanoparticles as Highly Effective Peroxidase Mimics: Synthesis, Characterization, and Application in Biosensing

Peroxidase mimics made of inorganic nanomaterials as alternatives to natural peroxidases have been extensively developed over the past few decades, owing to their superior properties relative to their natural counterparts. Nevertheless, it has been still a challenge to substantially enhance the catalytic efficiency of peroxidase mimics. In this work, we report a type of highly efficient peroxidase mimics that are made of iridium nanoparticles (Ir NPs) with rough surfaces. The Ir NPs possess an ultrahigh catalytic efficiency with a catalytic constant (Kcat) at the regime of 1010 s-1, orders of magnitude higher than the Kcat of horseradish peroxidase as a natural peroxidase. As a proof-of-concept demonstration, the Ir NPs were applied to colorimetric lateral flow assay (CLFA). Using carcinoembryonic antigen as a model disease biomarker, the Ir NPs-based CLFA achieved a low limit of detection (LoD) of 39 pg/mL, which was ~28 times lower than the LoD of conventional gold nanoparticles-based CLFA using the same antibodies.