Electrification of the chemical industry has been considered an enabler for energy transition on a massive scale. In this context, carbon monoxide electroreduction (COR) to produce multi-carbon (C ) products is considered one of the forefront emerging technologies. The key challenge in COR comes from the excessive cation crossover to the cathode via electromigration and water diffusion, which limits CO availability and impedes product selectivity.
View Article and Find Full Text PDFSingle atom catalysts (SACs) possess unique catalytic properties due to low-coordination and unsaturated active sites. However, the demonstrated performance of SACs is limited by low SAC loading, poor metal-support interactions, and nonstable performance. Herein, we report a macromolecule-assisted SAC synthesis approach that enabled us to demonstrate high-density Co single atoms (10.
View Article and Find Full Text PDFThe requirement of concentrated carbon dioxide (CO ) feedstock significantly limits the economic feasibility of electrochemical CO reduction (eCO R) which often involves multiple intermediate processes, including CO capture, energy-intensive regeneration, compression, and transportation. Herein, a bifunctional gas diffusion electrode (BGDE) for separation and eCO R from a low-concentration CO stream is reported. The BGDE is demonstrated for the selective production of ethylene (C H ) by combining high-density-polyethylene-derived porous carbon (HPC) as a physisorbent with polycrystalline copper as a conversion catalyst.
View Article and Find Full Text PDFApplications of small organic molecules and hydrogen-bonded aggregates, instead of traditional transition-metal-based electrocatalysts, are gaining momentum for addressing the issue of low-cost generation of H to power a sustainable environment. Such systems offer the possibility to integrate desired functional moieties with predictive structural repetition for modulating their properties. Despite these advantages, hydrogen-bonded organic systems have largely remained unexplored, especially as electrocatalysts.
View Article and Find Full Text PDFMetal-organic frameworks (MOFs) not only combine globally demanded renewable energy generation and environmental remediation onto a single platform but also rationalize structure-performance synergies to devise smarter materials with remarkable performance. The robust and non-interpenetrated cationic MOF exemplifies a unique bifunctional scaffold for the efficient electrochemical oxygen evolution reaction (OER) and ultrasensitive monitoring of biohazards. The microporous framework containing Brønsted acid-functionalized [Co(μ-OH)(CO)] secondary building units (SBUs) exhibits remarkable OER performance in 1 M KOH, requiring 410 mV overpotential to obtain 10 mA cm anodic current density, and a low Tafel slope of 55 mV/dec with 93.
View Article and Find Full Text PDFInternal Ni-vacancy-enriched spherical AuNi nanoalloys (AuNi-T) have been prepared via a noble electrochemical etching method. AuNi-T showed the highest oxygen evolution reaction (OER) activity compared to bare AuNi, and it demands only 239 mV overpotential, which was 134 mV lesser than the overpotential required by commercial RuO at 10 mA cm current density in a 1 M KOH solution (pH = 14). The calculated turnover frequency (TOF) value for AuNi-T (0.
View Article and Find Full Text PDFDevelopment of a low-cost transition metal-based catalyst for water splitting is of prime importance for generating green hydrogen on an industrial scale. Recently, various transition metal-based oxides, hydroxides, sulfides, and other chalcogenide-based materials have been synthesized for developing a suitable anode material for the oxygen evolution reaction (OER). Among the various transition metal-based catalysts, their oxides have received much consideration for OER, especially in lower pH condition, and MnO is one of the oxides that have widely been used for the same.
View Article and Find Full Text PDFThe replacement of noble metals with alternative electrocatalysts is highly demanded for water splitting. From the exploration of 3D -transition metal based heterostructures, engineering at the nano-level brought more enhancements in active sites with reduced overpotentials for both the oxygen evolution reaction (OER) and hydrogen evolution reaction (HER). However, recent developments in 3D transition metal based heterostructures like direct growth on external substrates (Ni foam, Cu foam) gave highly impressive activities and stabilities.
View Article and Find Full Text PDFThe development of a highly efficient electrocatalyst for the oxygen evolution reaction (OER) with a lower overpotential and high intrinsic activity is highly challenging owing to its sluggish kinetic behavior. As an alternative to the state-of-the-art OER catalyst, recently, transition-metal-based hydroxide materials have been shown to play important roles for the same. Owing to the high earth abundance of various Ni-based hydroxide and its derivatives, these are known to be highly studied materials for the OER.
View Article and Find Full Text PDFDirect methanol fuel cell technology implementation mainly depends on the development of non-platinum catalysts with good CO tolerance. Among the widely studied transition-metal catalysts, cobalt oxide with distinctively higher catalytic efficiency is highly desirable. Here, we have evolved a simple method of synthesizing cobalt tungsten oxide hydroxide hydrate nanowires with DNA (CTOOH/DNA) and without incorporating DNA (CTOOH) by microwave irradiation and subsequently employed them as electrocatalysts for methanol oxidation.
View Article and Find Full Text PDFDeveloping non-noble, earth-ample, and stable electrocatalysts are highly anticipated in oxygen-evolution reaction (OER) and hydrogen-evolution reaction (HER) at unique pH conditions. Herein, we have synthesized bimetallic (nickel and iron) zeolite imidazolate framework (ZIF)-based nanofibrous materials via a simple electrospinning (ES) process. The structural stability of the fibrous material is subjected to various calcination conditions.
View Article and Find Full Text PDFMetal-organic framework (MOF)-based materials have attracted attention in recent times owing to their remarkable properties such as regulatable pore size, high specific surface area, and elasticity in their network topology, geometry, dimension, and chemical functionality. It is believed that the incorporation of a MOF network into a fibrous matrix results in the improvement of the electrocatalytic properties of the material. Herein, we have synthesized a Co-incorporated MOF-5-based fibrous material by a simple wet-chemical method, followed by an electrospinning (ES) process.
View Article and Find Full Text PDFThe catalytic activity of 3d-transition-metal-based electrocatalysts has exhibited considerable enhancements in electrocatalytic water splitting via pioneering modulations in the active sites. To overcome the energy loss because of the mechanic steps involved in a complex oxygen evolution reaction (OER), the electrode surface with only a few layers would be an advantage over multilayers for the ease of the electrolyte interaction and gas evolution. Here, for the first time, thin films of CoS are prepared on a carbon cloth via a pulsed laser deposition (PLD) technique via layer-by-layer deposition of Ni that tend to give Ni-CoS thin films.
View Article and Find Full Text PDFThe use of nanomaterials (NMs) in various applications via multidisciplinary approaches is highly necessary in this era. In this line, the impact of noble metals in organic media for both catalysis and surface-enhanced Raman spectroscopic (SERS) studies is most interesting and also has a wider scope in various fields. Nonetheless, the catalytic reduction of aromatic nitro compounds is difficult with poor solubility in aqueous media, and reduction also is less feasible in the absence of noble metal-based catalysts.
View Article and Find Full Text PDFSurface Enhanced Raman Scattering (SERS) is a field of research that has shown promising application in the analysis of various substrate molecules by means of rough metallic surfaces. In directing the enhancement of substrate molecules in micro and nano-molar concentrations, plasmonic coupling of metal nanoparticles (NPs), morphology of metal NPs and the closely arrangement of rough metal surfaces that produces 'hot spots' can effectively increase the so-called enhancement factor (EF) that will be applicable in various fields. As the mechanistic aspects are still not clear, research has been triggered all over the world for the past two decades to have a clear understanding in chemical and electromagnetic effects.
View Article and Find Full Text PDFOut of various available methods, generation of hydrogen by electrocatalytic water splitting is the most accepted one which consists of two half-cell reactions, , oxygen evolution reaction (OER) at the anode and hydrogen evolution reaction at the cathode. OER is a complex four-electron transfer process, and to sustain the spontaneous generation of hydrogen at the cathode, it is urgent to develop some earth-abundant, low-cost electrode materials. Recently, use of cobalt-based hydroxide as the electrode substrate has taken much consideration and has been fabricated over various substrates.
View Article and Find Full Text PDFProduction of hydrogen by water electrolysis is an environment-friendly method and comparatively greener than other methods of hydrogen production such as stream reforming carbon, hydrolysis of metal hydride, etc. However, sluggish kinetics of the individual half-cell reactions hinders the large-scale production of hydrogen. To minimize this disadvantage, finding an appropriate, competent, and low-cost catalyst has attracted attention worldwide.
View Article and Find Full Text PDFDepolymerization of lignin biomass to its value-added chemicals and fuels is pivotal for achieving the goals for sustainable society, and therefore has acquired key interest among the researchers worldwide. A number of distinct approaches have evolved in literature for the deconstruction of lignin framework to its mixture of complex constituents in recent decades. Among the existing practices, special attention has been devoted for robust site selective chemical transformation in the complex structural frameworks of lignin.
View Article and Find Full Text PDFCatalyst development for the efficient direction of electrocatalytic water splitting with much less overpotential is crucial for meeting large-scale hydrogen generation. Being highly abundant and cost-effective, 3d transition-metal-based catalysts show promising activities in alkaline conditions. In this work, bimetallic nickel-cobalt carbonate hydroxide hydrate (NiCoCHH) was prepared by a co-precipitation method with varying molar ratios of Ni/Co of 0.
View Article and Find Full Text PDFThe biomolecule DNA with the presence of different functionalities found to interact with different kinds of metal ions and show relatively higher stability over a long period of time when optimized appropriately. With the presence of A-T and G-C pairs, sugar moieties, phosphate functional groups and the double-helical structure, it can assemble both cationic and anionic species and forms a perfect metal-DNA self-assembly. Depending upon the aspect ratio of metal-DNA self-assemblies, metal content and their morphological outcomes, they could deliver variance in the catalytic activities.
View Article and Find Full Text PDFHighly efficient and earth-abundant elements capable of water reduction by electrocatalysis and are attractive for the sustainable generation of fuels. Among the earth-abundant metals, copper is one of the cheapest but often the most neglected choice for the hydrogen evolution reaction (HER) due to its high overvoltage. Herein, for the first time we have tuned the overpotential of copper by tellurizing it by two different methodologies, viz.
View Article and Find Full Text PDFEffective hydrogen (H) production with surface engineering of less active catalysts by an innovative approach is followed here. In this work, a non-noble 2H phase of VS layers, which showed poor activity for hydrogen evolution reaction (HER) in 0.5 M HSO, was made highly active by decorating palladium (Pd) nanoparticles (NPs) over VS layers.
View Article and Find Full Text PDFZeolite imidazolate frameworks (ZIFs) are a subclass of metal organic frameworks (MOFs) and have been considered as a special finding in the current platform of the research arena. ZIFs have been comprised of metal ions with imidazolate linkers. In recent times, ZIFs have been predominately utilized for various applications.
View Article and Find Full Text PDFCatalyzing oxygen evolution reaction (OER) with the lowest possible overpotential is a key to ensure energy efficiency in the production of hydrogen from water electrochemically. In this report, we show the results that astonished us. Co hydroxide containing trivalent V was prepared chemically and screened for electrochemical water oxidation in rigorously Fe free 1 M KOH (pH 13.
View Article and Find Full Text PDFOne-dimensional (1D) based carbonaceous materials have wider applicability owing to flexibility over their properties. Electrospinning is one of the pioneering techniques that is being utilized predominantly for the synthesis of fibers. Fibrous material has their own advantages like, high porosity over its surface, mechanical stability and fascinating physicochemical properties.
View Article and Find Full Text PDF