Electrochemistry represents one of the most intimate ways of interacting with molecules. This review discusses advances in synthetic organic electrochemistry since 2000. Enabling methods and synthetic applications are analyzed alongside innate advantages as well as future challenges of electroorganic chemistry.

Synthetic Organic Electrochemical Methods Since 2000: On the Verge of a Renaissance

The applications of copper (Cu) and Cu-based nanoparticles, which are based on the earth-abundant and inexpensive copper metal, have generated a great deal of interest in recent years, especially in the field of catalysis. The possible modification of the chemical and physical properties of these nanoparticles using different synthetic strategies and conditions and/or via postsynthetic chemical treatments has been largely responsible for the rapid growth of interest in these nanomaterials and their applications in catalysis. In addition, the design and development of novel support and/or multimetallic systems (e.g., alloys, etc.) has also made significant contributions to the field. In this comprehensive review, we report different synthetic approaches to Cu and Cu-based nanoparticles (metallic copper, copper oxides, and hybrid copper nanostructures) and copper nanoparticles immobilized into or supported on various support materials (SiO2, magnetic support materials, etc.), along with their applications i...

http://pubs.acs.org/doi/pdfplus/10.1021/acs.chemrev.5b00482

Cu and Cu-Based Nanoparticles: Synthesis and Applications in Catalysis.

Hydrogen fuel is considered as the cleanest renewable resource and the primary alternative to fossil fuels for future energy supply. Sustainable hydrogen generation is the major prerequisite to realize future hydrogen economy. The electrocatalytic hydrogen evolution reaction (HER), as the vital step of water electrolysis to H2 production, has been the subject of extensive study over the past decades. In this comprehensive review, we first summarize the fundamentals of HER and review the recent state-of-the-art advances in the low-cost and high-performance catalysts based on noble and non-noble metals, as well as metal-free HER electrocatalysts. We systemically discuss the insights into the relationship among the catalytic activity, morphology, structure, composition, and synthetic method. Strategies for developing an effective catalyst, including increasing the intrinsic activity of active sites and/or increasing the number of active sites, are summarized and highlighted. Finally, the challenges, perspectives, and research directions of HER electrocatalysis are featured.

Recent Advances in Electrocatalytic Hydrogen Evolution Using Nanoparticles.

Photoreduction of CO2 into sustainable and green solar fuels is generally believed to be an appealing solution to simultaneously overcome both environmental problems and energy crisis. The low selectivity of challenging multi-electron CO2 photoreduction reactions makes it one of the holy grails in heterogeneous photocatalysis. This Review highlights the important roles of cocatalysts in selective photocatalytic CO2 reduction into solar fuels using semiconductor catalysts. A special emphasis in this review is placed on the key role, design considerations and modification strategies of cocatalysts for CO2 photoreduction. Various cocatalysts, such as the biomimetic, metal-based, metal-free, and multifunctional ones, and their selectivity for CO2 photoreduction are summarized and discussed, along with the recent advances in this area. This Review provides useful information for the design of highly selective cocatalysts for photo(electro)reduction and electroreduction of CO2 and complements the existing reviews on various semiconductor photocatalysts.

Cocatalysts for Selective Photoreduction of CO2 into Solar Fuels.

(1990). ENERGY FUNCTION ANALYSIS FOR POWER SYSTEM STABILITY. Electric Machines & Power Systems: Vol. 18, No. 2, pp. 209-210.

Energy function analysis for power system stability

Well-separated Si/ZnS radial nanowire heterojunction-based light-emitting devices have been fabricated on large-area substrates by depositing n-ZnS film on p-type nanoporous Si nanowire templates. Vertically oriented porous Si nanowires on p-Si substrates have been grown by metal-assisted chemical etching catalyzed using Au nanoparticles. Isolated Si nanowires with needle-shaped arrays have been made by KOH treatment before ZnS deposition. Electrically driven efficient white light emission from radial heterojunction arrays has been achieved under a low forward bias condition. The observed white light emission is attributed to blue and green emission from the defect-related radiative transition of ZnS and Si/ZnS interface, respectively, while the red arises from the porous surface of the Si nanowire core. The observed white light emission from the Si/ZnS nanowire heterojunction could open up the new possibility to integrate Si-based optical sources on a large scale.

Fabrication of Si/ZnS Radial Nanowire Heterojunction Arrays for White Light Emitting Devices on Si Substrates

Here we report a modified hydrothermal (MHT) reaction to substantiate the nucleation, growth and reversible dehydration of a well defined uranium oxide hydroxide hydrate (UOHH) species, (UO2)8O2(OH)12(H2O)12 to fabricate a morphologically different array of well defined nanoplates. The reaction between uranyl acetate (UA) and triethylamine (TEA) from an aqueous phase has revealed a new role of TEA for alternation of shapes, aspect ratio and columnar stacking of the nanoplates. Interesting morphology alternation of (UO2)8O2(OH)12(H2O)12 nanoplates and furthermore, their secondary growth have been highlighted by manipulating the ratio of UA to TEA and reaction time. Then we found citrate as a capping agent for selective planes of the nanoplates as a result of which nanoplates assembled to the flowery structures or columnar stacking, depending on the citrate concentration. The structure and morphology of all the products have been characterized by means of X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM). It has also been reported that upon calcination at ∼700 °C the nanoplates are converted to U3O8 but with the retaintion of their morphology. Furthermore, in situsilver nanoparticles loading in the UOHH nanoplates has been described for the first time using photochemical technique to make the nanoplates SERS active. Fluorescence property (λem = 520 nm) and finally very high catalytic activity of the UOHH nanoplates over U3O8 towards benzyl alcohol oxidation has been discussed.

Morphology controlled uranium oxide hydroxide hydrate for catalysis, luminescence and SERS studies

Superparamagnetic monodispersed spherical β-MnO2 nanoparticles of ∼10 nm size with a band gap of 2.52 eV have been synthesized in toluene and support the oxidative phenol coupling reaction as a photocatalyst.

Synthesis of Superparamagnetic β-MnO2 Organosol: a Photocatalyst for the Oxidative Phenol Coupling Reaction

Oxidation of β-asarone (2) with DDQ gave trans-2,4,5-trimethoxycinnamaldehyde (3), which on treatment with p-toluenesulfonyl hydrazine provided corresponding α,β-unsaturated hydrazone derivative (4). Reduction of 4 with sodium borohydride in acetic acid afforded γ-asarone (1) in 43% yield.

A Mild and Convenient Procedure for the Conversion of Toxic β-Asarone into Rare Phenylpropanoids: 2,4,5-Trimethoxycinnamaldehyde and γ-Asarone†

Surface chemical properties of metal nanoparticles must be tunable to create chemical specificity and are a key prerequisite for successful sensing and imaging platforms. To relate surface enhanced Raman scattering (SERS) to electrostatic field force, a simple colloidal chemistry approach has been deliberately exploited for syntheses of gold nanoparticles with negative and positive surface charges to study their interactions with charged analytes. We took up the challenge with sulfur-containing analytes because “Au−S” interaction is well-known. Thiocyanate ion, −SCN−, a well-known SERS analyte, has been proved to be chemically ligated/anchored on positively charged gold nanoparticles surface owing to favorable electrostatic attraction. The Au−S vibrational band at ∼240 cm−1 and blue-shifting of the −C≡N stretching frequency by ∼46 cm−1 in conjunction with its intensity enhancement by an order of ∼103 in the SERS spectrum clearly illustrate a chemisorption phenomenon. In contrast, physisorption of the −SCN...

Arun Kumar Sinha

Papers

Fabrication of Si/ZnS Radial Nanowire Heterojunction Arrays for White Light Emitting Devices on Si Substrates

Morphology controlled uranium oxide hydroxide hydrate for catalysis, luminescence and SERS studies

Synthesis of Superparamagnetic β-MnO2 Organosol: a Photocatalyst for the Oxidative Phenol Coupling Reaction

A Mild and Convenient Procedure for the Conversion of Toxic β-Asarone into Rare Phenylpropanoids: 2,4,5-Trimethoxycinnamaldehyde and γ-Asarone†

Exploration of Electrostatic Field Force in Surface-Enhanced Raman Scattering: An Experimental Investigation Aided by Density Functional Calculations