Due to the chemical stability of graphene, synthesis of carboxylated graphene still remains challenging during the electrochemical exfoliation of graphite. In this work, a spatially confined radical addition reaction which occurs in the sub-nanometer scaled interlayers of the expanded graphene sheets for the electrochemical synthesis of highly stable carboxylated graphene is reported. Here, formate anions act as both intercalation ions and co-reactant acid for the confinement of electro-generated carboxylic radical (COOH) in the sub-nanometer scaled interlayers, which facilitates the radical addition reaction on graphene sheets.
View Article and Find Full Text PDFElectro-optical synergy has recently been targeted to improve the separation of hot carriers and thereby further improve the efficiency of plasmon-mediated chemical reactions (PMCRs). However, the electro-optical synergy in PMCRs needs to be more deeply understood, and its contribution to bond dissociation and product selectivity needs to be clarified. Herein, the electro-optical synergy in plasmon-mediated reduction of -bromothiophenol (PBTP) was studied on a plasmonic nanostructured silver electrode using in situ Raman spectroscopy and theoretical calculations.
View Article and Find Full Text PDFPlasmon-mediated electrochemistry is an emerging area of interest in which the electrochemical reactions are enhanced by employing metal nanostructures possessing localized surface plasmon resonance (LSPR). However, the reaction efficacy is still far below its theoretical limit due to the ultrafast relaxation of LSPR-generated hot carriers. Herein, we introduce -hydroxythiophenol (PHTP) as a molecular cocatalyst to significantly improve the reaction efficacy in plasmon-mediated electrochemical oxidation of -aminothiophenol (PATP) on gold nanoparticles.
View Article and Find Full Text PDFIt is highly challenging to activate the basal plane and minimize the π-π stacking of MoS sheets, thus enhancing its catalytic performance. Here, we display an approach for making well-dispersed MoS . By using the N-doped multi-walled carbon nanotubes (NMWCNTs) as an isolation unit, the aggregation of MoS sheets was effectively reduced, favoring the dispersion of Pt nanoparticles (noted as Pt/NMWCNTs-isolated-MoS ).
View Article and Find Full Text PDFSurface-enhanced Raman spectroscopy (SERS) has been widely applied in the identification and characterization of DNA structures with high efficiency. Especially, the SERS signals of the adenine group have exhibited high detection sensitivity in several biomolecular systems. However, there is still no unanimous conclusion regarding the interpretation of some special kinds of SERS signals of adenine and its derivatives on silver colloids and electrodes.
View Article and Find Full Text PDFBifunctional oxygen electrocatalysts that hold outstanding activity and stability are highly crucial for the development of efficient rechargeable Zn-air batteries. Herein, cobalt-molybdenum-based bimetallic carbide and cobalt nanoparticles embedded N-doped carbon nanocages are synthesized via the pyrolysis of functionalized zeolitic imidazolate framework precursor originated from zeolitic imidazolate framework sequentially coated with polydopamine and phosphomolybdic acid. Furthermore, we revealed the composition-performance relationship based on the exploration of bifunctional performance on the pyrolysis products.
View Article and Find Full Text PDFElectrocatalytic hydrogen evolution is an important approach to produce clean energy, and many electrocatalysts (e.g., platinum) are developed for hydrogen production.
View Article and Find Full Text PDFPhotocatalytic evolution of hydrogen is becoming a research hotspot because it can help to produce clean energy and reduce environmental pollution. Titanium dioxide (TiO) and its composites are photocatalysts that are widely used in hydrogen evolution because of their high abundance in nature, low price, and high photo/chemical stability. However, their catalytic performances still need to be further improved, particularly in the visible light spectrum.
View Article and Find Full Text PDFSurface plasmon resonance (SPR) bridges photonics and photoelectrochemistry by providing an effective interaction between absorption and confinement of light to surface electrons of plasmonic metal nanostructures (PMNs). SPR enhances the Raman intensity enormously in surface-enhanced Raman spectroscopy (SERS) and leads to the plasmon-mediated chemical reaction on the surface of nanostructured metal electrodes. To observe variations in chemical reactivity and selectivity, we studied the SPR photoelectrochemical reactions of -aminobenzoic acid (PABA) on nanostructured gold electrodes.
View Article and Find Full Text PDFAn attractive field of plasmon-mediated chemical reactions (PMCRs) is developing rapidly, but there is still incomplete understanding of how to control the kinetics of such a reaction related to hot carriers. Here, we chose 8-bromoadenine (8BrAd) as a probe molecule of hot electrons to investigate the influence of the electrode potential, laser wavelength, and power on the PMCR kinetics on silver nanoparticle-modified silver electrodes. Plasmonic hot electron-mediated cleavage of the C-Br bond in 8BrAd has been investigated by combining in situ electrochemical surface-enhanced Raman spectroscopy and density functional theory calculations.
View Article and Find Full Text PDFUltrason Sonochem
September 2020
Copper nanoparticles with the diameter of 50 ± 20 nm decorated nitrogen doped graphite oxide (NGO) have been prepared through a simple single step carbonization method using copper metal-organic framework (MOF), [Cu₂(BDC)₂(DABCO)] (where BDC is 1,4-benzenedicarboxylate, and DABCO is 1,4-Diazabicyclo[2.2.2]octane) as precursor.
View Article and Find Full Text PDFWe have described a hybrid material that consists of molybdenum disulfide nanosheets (MoS) coated on functionalized multiwalled carbon nanotubes (f-MWCNTs) for sensitive and selective determination of chloramphenicol (CAP). The MoS/f-MWCNTs nanocomposite was successfully prepared through a hydrothermal process and its structure was characterized by scanning electron microscopy, transmission electron microscopy, energy-dispersive X-ray spectroscopy, electrochemical impedance spectroscopy and cyclic voltammetry. The MoS/f-MWCNTs nanocomposite holds excellent electrochemical properties and it displays excellent electrocatalytic ability to CAP.
View Article and Find Full Text PDFSeveral nanomaterials and techniques for the detection of mercuric ions (Hg(2+)) have been developed in the past decade. However, simple, low-cost and rapid sensor for the detection of heavy metal ions yet remains an important task. Herein, we present a highly sensitive electrochemical sensor for the femtomolar detection of Hg(2+) based on polypyrrole, pectin, and graphene (PPy/Pct/GR) which was prepared by one step electrochemical potentiodyanamic method.
View Article and Find Full Text PDFA simple and rapid green synthesis using Bischofia javanica Blume leaves as reducing agent was developed for the preparation of gold nanoparticles (AuNPs). AuNPs decorated graphene oxide (AuNPs/GO) was prepared and employed for the sensitive amperometric determination of chloramphenicol. The green biosynthesis requires less than 40s to reduce gold salts to AuNPs.
View Article and Find Full Text PDFBiopolymer pectin stabilized gold nanoparticles were prepared at graphene and multiwalled carbon nanotubes (GR-MWNTs/AuNPs) and employed for the determination of glucose. The formation of GR-MWNTs/AuNPs was confirmed by scanning electron microscopy, X-ray diffraction, UV-vis and FTIR spectroscopy methods. Glucose oxidase (GOx) was successfully immobilized on GR-MWNTs/AuNPs film and direct electron transfer of GOx was investigated.
View Article and Find Full Text PDFAmitrole is a biologically toxic nonselective herbicide which contaminates surface and ground waters at unprecedented rates. All reported modified electrodes that detect amitrole within sub-micromolar to nanomolar levels were based on the electro-oxidation of amitrole. Herein, we developed a new conceptual idea to detect picomolar concentrations of amitrole based on calcium cross linked pectin stabilized gold nanoparticle (CCLP-GNP) film modified electrode which was prepared by electrodeposition.
View Article and Find Full Text PDFWe described a simple and facile chemical reduction strategy for the preparation of graphene (GR)-cobalt phthalocyanine (CoPc) composite and explored it for the enzymatic determination of glucose. CoPc is an active mediator and electrocatalysts for the immobilization of GOx and determination of glucose. However, it is not stable on the electrode surface and also suffers from lack of conductivity.
View Article and Find Full Text PDFA highly selective amperometric sensor was developed for the trace level determination of hydrazine at bismuth nanoparticles (Bi) decorated graphene nanosheets (GR) composite film modified glassy carbon electrode (GCE). GR-Bi nanocomposite has been successfully prepared via simple and facile chemical reduction approach and its structure was characterized by various techniques. Surface morphological and X-ray diffraction studies revealed the formation and high loading of Bi nanoparticles on graphene sheets.
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