Nanostructured Cobalt Research Articles

In situ formation of robust nanostructured cobalt oxyhydroxide/cobalt oxide oxygen evolution reaction electrocatalysts

The conversion of mixed metal sulfide precursors into active and robust metal oxide/hydroxide oxygen evolution reaction electrocatalysts is reported.

One-pot spray pyrolysis method for nanostructured cobalt sulfide–C composite microspheres using recovered cobalt sulfuric acid solution and their excellent properties as anode materials for potassium-ion batteries

A pioneering synthesis approach for nanostructured cobalt sulfide-C composites from waste materials is proposed. By combining recycling processes with one-pot spray pyrolysis, a cost-effective and efficient synthesis method is achieved.

(Keynote) Experimental and Computational Insights into Electronic Structure and Redox Properties of Bare and Doped Co3O4 Nanocrystals of Euhedral Morphology and Their Heterojunctions with Alien Oxides and Carbon Materials

One of the most attractive oxide materials with remarkable record of widespread applications are cobalt spinels and their derivatives obtained by doping with alien redox (3dn) and nonredox (Li) cations or via hybridization with other oxides (CeO2, TiO2, a-Al2O3) or carbon support. They have recently received a great deal of theoretical and practical attention because of an outstanding activity in many redox processes important for photo/electro/catalysis. Among many potential applications, their relevance as promising substitutes for platinum in oxygen reduction reaction (ORR) or oxygen evolution reaction (OER) can be mentioned, in particular. The properties of nanostructured cobalt spinel materials depend on their size, shape, doping and interfacing features. In this context, euhedral spinel nanocrystals that expose well defined crystallographic planes, allow for sensible investigations into establishment of the surface/bulk structure-redox reactivity relationships in real conditions.In this presentation application of S/TEM and inverse Wulff hull matching techniques supported by image simulation was discussed for elucidation the mechanism of hydrothermal synthesis of euhedral cobalt spinel nanocrystals the their shape retrieving. Periodic spin unrestricted DFT-PW91+U and hybrid DFT/HSE06 calculations were applied for modeling the morphology, structure and electronic properties (DOS structure) relevant for redox behavior of bare and doped cobalt spinel nanocrystals. The results allowed for thorough characterization of the structure and reconstruction of the exposed low index (100), (110), and (111) planes, and explain the influence of dopants. The effect of the valence state of lithium (Li+ or Li0), and its locus on the valence pining of the cobalt cations was determined. DFT calculations together with the ab initio thermodynamic modeling were used to study the electronic structure of the created defects, and stability of different terminations of cobalt spinel and Li-doped Co3O4 under various redox conditions. The associated electronic and spin relaxation processes were discussed as well. For the most stable stoichiometric (100) and (111) facets, the surface redox state diagrams in a wide stoichiometry range were constructed, and analyzed in detail. Intrinsic charge transfer processes involving electron (n-conductivity) and hole (p-conductivity) transfer between the octahedral and tetrahedral cobalt cations were modeled using a small polaron approximation (Marcus-Dupuis model). Formation of n-p junctions (Co3O4|CeO2, Li-Co3O4|CeO2) and MxCo3-xO4/carbon hybrids were analyzed by S/TEM, XPS spectroscopy (band alignment), contactless electronic conductivity and work function measurements, corroborated by DFT modeling. The redox properties of the interface and spinel faceting, and the role of electric conductivity and the nature of the carbon support functional groups were discussed in the context of the ORR, OER performance, and catalytic redox reactivity (activation of O2).AcknowledgmentsS.W. thanks for the financial support of the project “High-performance electrocatalyst for oxygen reduction reaction with low platinum content” carried on within the Program “Pearls of Science” of the Ministry of Education and Science of Poland.

The SYNTHESIS OF METAL NANOPARTICLES USING PLANTS TO ENHANCE THE GROWTH AND GERMINATION OF AGRICULTURAL CROPS

Nanoparticles of several metals obtained through biosynthesis have interesting pharmacological properties due to extract components' sorption on their surface, which broadens their application possibilities. For these reasons, the issue of metal nanoparticles synthesis biological ways optimization is highly important nowadays. Purpose of the work is to present experimental data on the synthesis of metal nanodispersions using plant extracts of Artemisia (wormwood), Psylliostachys (plantain), Achillea nobilis (yarrow) and use in growing crops. Methodology. A feature of this method is the use of a more environmentally friendly approach to the synthesis of nanoparticles by preparing extracts from plant materials. Plant raw materials for synthesis, synthesis conditions (temperature, pH value, ratio of metal salts: extract) were experimentally selected. It was found that in presence of extract from bitter wormwood nanoparticles formation occurs faster than in case of using Psylliostachys (plantain) or Achillea nóbilis (yarrow). Sythesized silver nanoparticles were studied using microscopy and spectroscopy. Results. Obtained particle sizes are between 70 and 100 µm, which proves nanostructured nickel and cobalt particles formed in synthesis. Average particle size is 80 µm. New growth stimulator М-Nitro-Ni,Co was used to increase annual grasses and vegetables growth and germination; as a result, they had stronger roots, thicker stems, dark-green leaves and larger size comparing to the test ones.

Non-Enzymatic Co3O4 Nanostructure-Based Electrochemical Sensor for H2O2 Detection

Abstract This article describes the synthesis of nanostructured cobalt oxide on iron wires and its application for the detection of hydrogen peroxide as working electrode for non-enzymatic electrochemical sensor. Cobalt oxide was obtained by the hydrothermal synthesis method using chloride and acetate anions. The resulting nanostructured coating obtained from the chloride precursor is a uniform homogeneous porous network of long nanofibers assembled into regular honeyсomb-like formations. In the case of an acetate precursor, instead of nanofibers, petal-like nanostructures assembled into honeycomb agglomerates are observed. The structure, surface, and composition of the obtained samples were studied using field-emission scanning electron microscopy along with energy-dispersive spectroscopy and X-ray diffractometry. The resultant nanostructured specimens were utilized to detect H2O2 electrochemically through cyclic voltammetry, differential pulse voltammetry, and i-t measurements. A comparative research has demonstrated that the nanostructures produced from the chloride precursor exhibit greater sensitivity to H2O2 and have a more appropriate morphology for designing a nanostructured sensor. A substantial linear correlation between the peak current and H2O2 concentration within the 20 to 1300 μM range was established. The Co3O4 electrode obtained exhibits a sensitivity of 505.11 μA·mM−1, and the electroactive surface area is calculated to be 4.684 cm2. Assuming a signal-to-noise ratio of 3, the calculated limit of detection is 1.05 μM. According to the interference study, the prevalent interfering agents, such as ascorbic acid, uric acid, NaCl, and glucose, do not influence the electrochemical reaction. The obtained results confirm that this sensor is suitable for working with complex analytes.The actual sample assessment demonstrated a recovery rate exceeding 95 %.

Transition Metal Catalysts for Atmospheric Heavy Metal Removal: A Review of Current Innovations and Advances.

Atmospheric heavy metal pollution presents a severe threat to public health and environmental stability. Transition metal catalysts have emerged as a potent solution for the selective capture and removal of these pollutants. This review provides a comprehensive summary of current advancements in the field, emphasizing the efficiency and specificity of nanostructured transition metals, including manganese, iron, cobalt, nickel, copper, and zinc. Looking forward, we delve into the prospective trajectory of catalyst development, underscoring the need for materials with enhanced stability, regenerability, and environmental compatibility. We project that advancements in computational materials science, nanotechnology, and green chemistry will be pivotal in discovering innovative catalysts that are economically and environmentally sustainable. The integration of smart technologies for real-time monitoring and adaptive control is anticipated to revolutionize heavy metal remediation, ensuring efficient and responsive pollution abatement strategies in the face of evolving industrial scenarios and regulatory landscapes.

Observation on structural and optical features of new nanostructured lead-free methylammonium zinc or cobalt iodide perovskites for solar cells applications

The toxicity of lead-based halide perovskites has become a significant drawback to be employed in optoelectronic devices. Therefore, developing other environmentally friendly candidates with tunable optoelectronic properties for highly efficient solar cells is indispensable. Lead-free perovskite solar cells (PSCs) are promising to have a crucial role in large-scale commercial non-toxic photovoltaic devices. Here, the microstructure and optoelectronic properties of 2D halide perovskites without pb (CH3NH3)2BI4 (where B = Zn or Co) have been investigated for use in solar cells. The synthesized samples are characterized by X-ray diffraction (XRD), Raman spectroscopy, FT-IR, FESEM, and TEM. The variation in the optical and photoluminescence (PL) is recognized. The results indicate that (CH3NH3)2ZnI4 and (CH3NH3)2CoI4 crystals demonstrate a wide band gap of about 2.42 and 1.87 eV, respectively. A comparative study is presented for the optical properties of Zn- versus Co-based perovskites. It is noticed that Co is a better candidate than Zn to be a good replacement choice for Pb as Co-containing compounds have lower optical bandgap than Zn-containing compounds. PCBM is employed as a hole transport material, and PEDOT:PSS as an electron transport layer. The p-i-n PSCs are fabricated, and the electrical parameters are measured, obtaining power conversion efficiencies (PCE) of 0.73 and 2.45% for (CH3NH3)2ZnI4 and (CH3NH3)2CoI4, respectively. This work opens the door for further investigations to increase the PCE of both devices.

Electrochemical synthesis and characterization of high-purity cobalt nanostructures from CoCl2·6H2O dissolved in ethylene glycol-based nonaqueous solutions

Electrochemical synthesis and characterization of high-purity cobalt nanostructures from CoCl2·6H2O dissolved in ethylene glycol-based nonaqueous solutions

Growth Dynamics‐Dependent Chemical Approach to Accomplish Nanostructured Cobalt Vanadium Oxide Thin Film Electrodes with Controlled Surface Area for High‐Performance Solid‐State Hybrid Supercapacitor Devices

Rational designing of electrode materials having high surface area can accomplish the enhanced charge‐storing ability of the electrochemical energy storage devices. Therefore, the surface area of cobalt vanadium oxide (CVO) material is controlled by changing growth dynamics in successive ionic layer adsorption and reaction methods. Structural analysis confirms the formation of hydrous cobalt vanadium oxide nanoparticles (Co3V2O8⋅nH2O) thin film electrodes, and alteration in the surface area with change in growth dynamics is observed in Brunauer–Emmett–Teller analysis. The CVO1:1 thin film electrode prepared at optimal growth dynamics illustrates high specific capacitance (Cs) (capacity) of 793 F g−1 (396.7 C g−1) at 0.5 A g−1, respectively. Moreover, aqueous hybrid supercapacitor devices constructed using CVO1:1 as cathode exhibit high Cs of 133.5 F g−1 at 1.1 A g−1, specific energy (SE) of 47.7 Wh kg−1 with specific power (SP) of 0.90 kW kg−1. The solid‐state hybrid supercapacitor devices also offer high Cs of 102.9 F g−1 at 0.3 A g−1, SE of 36.6 Wh kg−1 at SP of 0.30 kW kg−1. In the SILAR approach, the dipping time plays a critical role in improving the surface area of the material and, consequently, electrochemical performance, as the current work amply indicates.

Defect states in graphene oxide mixed nanostructured calcium cobalt oxide

Nanostructured materials of calcium cobalt oxide (Ca3Co4O9, CCO) is realized by mix-grinding the as-synthesized CCO with graphene oxide (GO) and investigated its influence on microstructure, crystallographic phase, thermal/chemical stability, molecular bonding, composition, and optical behaviour. Increasing GO weight percentage (wt%) from 0.1 to 10 in the CCO and GO mixture (CCO-GO) shows decrease in particle size with uniformly distributed sub-50 nm CCO particles and weight loss of ∼18.88% for 10 wt% GO. Structural and spectroscopic analysis of the resulting CCO-GO nanocomposites reveal coexistence of highly pure CCO and GO without comprising their inherent properties after mix-grinding. The tri-exponential behavior with weighted average lifetime of 1.21 ns in time resolved photoluminescence spectra suggest three different fundamental carrier recombination dynamics resulting from electronic transitions and photon emissions following various radiative and non-radiative processes in UV and visible range, and is attributed to the presence of defect states in CCO-GO nanostructures. The currently developed novel approach of achieving nanostructured CCO by mixing GO using an elementary and economical method of ball-milling, and conceptual understanding for presence of oxygen vacancy involved defect levels could be beneficial in developing new materials for utilization in highly efficient device applications.

Revealing electronic structure of nanostructured cobalt titanate via a combination of optical and electrochemical approaches toward water splitting and CO2 reduction

AbstractBackgroundThe shortage of clean energy has become a serious problem due to the rapid development of societies and the increasing consumption of fossil fuels. Metal oxide semiconductor nanomaterials have been studied as photo‐/electrocatalysts for water splitting in terms of clean energy generation. Applications of semiconductors depend on their electronic structures. Therefore, elucidating the electronic diagram is essential for determining the specific applications of novel semiconductors.ResultsHerein, we demonstrate using a combination of UV–visible diffuse reflectance spectroscopy (DRS) and Mott–Schottky analysis via electrochemical impedance spectroscopy for sketching the electronic diagram of nanostructured cobalt titanate (CoTiO3) prepared by the sol–gel method. UV–visible DRS studies reveal a band gap of 2.5 and 2.1 eV for direct and indirect transitions of prepared nanostructured materials, respectively. Mott–Schottky analysis shows a 0.8 V versus Ag/AgCl value for the flat band potential for CoTiO3. We further show the application of this diagram toward the interpretation of the electrochemical behavior of nanostructured CoTiO3 for electrochemical water splitting reactions and the electrochemical CO2 reduction reaction (eCO2RR).ConclusionThe presented electrochemical and photoelectrochemical studies demonstrate nanostructured CoTiO3 as an effective catalyst for electrochemical water oxidation and the eCO2RR. Moreover, our results provide valuable information for further investigation of water splitting and photovoltaic energy conversion. © 2023 Society of Chemical Industry (SCI).

The Effect of Full-Scale Exchange of Ca2+ with Co2+ Ions on the Crystal Structure and Phase Composition of CaHPO4·2H2O

The influence of ionic substitution in the Ca1−xCoxHPO4·nH2O compound was studied systematically for the first time. Among the fascinating features of these biomaterials is that they can be easily tailored for specific applications, for example, as biocements and bioceramics. Different molar concentrations of Co(NO3)2·6H2O, Ca(NO3)2·4H2O, and NaH2PO4·2H2O compounds were employed in determining the starting solutions utilized in the present study. The experimental findings reveal that, when the Co/Ca molar ratio is below 0.67 (BCo4), Co doping (the partial substitution of Ca by Co) takes place in brushite as a monophase. However, in the Co/Ca 0.67–1.5 molar ratio range (BCo4–BCo6), biphasic Co3(PO4)2·8H2O/CaHPO4·2H2O crystals start to precipitate. Full Ca replacement by Co results in the precipitation of nanostructured monoclinic cobalt phosphate and orthorhombic ammonium cobalt phosphate hydrate. Subsequent X-ray photoelectron spectroscopy (XPS), powdered X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) analyses, along with thermogravimetric analysis (TGA), confirmed that the starting solution ratio of Co/Ca had a significant influence on the material’s microstructure, while tuning this ratio ultimately tailored the desired properties of the material for the intended applications.

Highly efficient electrocatalytic hydrogen generation in neutral water by a nanostructured cobalt catalyst derived in-situ from ionic liquid tagged cobalt terpyridine

Electrocatalytic hydrogen production in a neutral aqueous medium is a promising, safe and economically viable technology to obtain clean and carbon-free fuel. Herein, we report the design and synthesis of ionic liquid (IL) tagged water soluble cobalt terpyridine (Co-ttpy-IL) and bis-terpyridine (Co-bisttpy-IL) complexes and their application towards electrocatalytic hydrogen generation in neutral water. The structure of Co-ttpy-IL complex was confirmed by single crystal XRD analysis. Initial electrochemical investigation on the prepared complexes by cyclic voltammetry (CV) revealed two sets of redox peaks corresponding to redox couples CoIII/CoII and CoII/CoI. Further, the electrocatalytic properties were investigated in organic medium with acetic acid acting as an external proton source, which revealed superior catalytic behaviour of the prepared complexes towards hydrogen evolution reaction (HER). Since, the complexes are water soluble, HER was performed by electrolysis at a fixed potential (−0.72 V vs RHE) for 10 h, during which evolution of H2 gas was observed. In the case of Co-ttpy-IL, deposition of certain electroactive nanostructured material on the electrode surface was observed after the electrolysis. This material was later identified as CoO nanoflakes, stabilized with the heteroatoms present in the ligand system and IL moiety. Interestingly, thus formed CoO/SPE demonstrated fascinating electrocatalytic activity towards HER, which produced hydrogen at −0.495 V (vs RHE) for 10 h without any loss in the activity (94% faradaic efficiency) in neutral water.

Fabrication of CuCo2S4 on composite interface materials made of polypyrrole and nitrogen-doped carbon nanotubes for use in supercapacitors

Due to their low cost, high conductivity, and synergistic impact, the ternary CuCo2S4 sulfides were thoroughly examined in this article as electrode materials for electrochemical properties. The hydrothermal reaction process for energy storage application was aided by the nanostructured copper cobalt sulfides (CuCo2S4) secured on multiwalled carbon nanotubes/polypyrrole composite via ultrasonication. By utilizing a 6 M KOH electrolyte, the produced composite electrode displays increased specific capacitances and cyclic stability. The structural, morphological, and surface properties of the composite materials were analyzed using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Energy-dispersive X-ray spectroscopy (EDS), X-ray photo electron spectroscopy (XPS), Field emission scanning electron microscopy (FE-SEM), the Brunauer-Emmett-Teller (BET) theory, and the Barrett, Joyner, For better supercapacitor use, the morphological characteristics of nanoscale CuCo2S4 on NMWCNT/PPy surface were confirmed. The synthesized CuCo2S4@NMWCNT and CuCo2S4@NMWCNT/PPy composite electrodes shown outstanding cyclic stability up to 5000 cycles and specific capacitances of 259 F/g, respectively, at 1 A/g. The synthesized ternary composite electrode's electrochemical impedance spectroscopy (EIS) characteristics reveal the lowest Rs (0.53 and 0.63) and charge transfer resistance (Rct) as 65.6 Ω, as well as reasonably outstanding retention of 90.5 % after 5000 cycles. Through the use of a three-electrode configuration, the increased surface and morphological features of the CuCo2S4 on NMWCNT/PPy composite boosted the electrochemical properties of the ternary composite electrode.

Loading nano-rod cobalt phthalocyanine onto nitrogen-doped graphene and its application in photodegradation reaction under visible-light

The preparation of nanostructure cobalt phthalocyanine/nitrogen-doped graphene (CoPc/NG) composite is described in this contribution. The products were characterized by X-ray diffraction (XRD), FT-IR, Raman spectrometer, X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and energy dispersive spectroscopy (EDS and Map). The photocatalytic activity of the final product was tested for degradation of 2,4-dichlorophenol (DCP), as a probe contaminant under visible-light irradiation. The result shows that the DCP degradation efficiency is increased with a hybrid of CoPc and nitrogen-doped graphene (NG). This composite could eliminate about 80% of DCP (50 mL, 40 mg L-1) within 135 min. The study of kinetic models showed that the DCP degradation process follows pseudo first-order kinetics. The prepared CoPc/NG composite containing an appropriate dose of nitrogen exhibited the highest reaction rate constant in comparison with other catalysts.

Sol-gel synthesis of nanostructured cobalt oxide in four different ionic liquids

In this paper we report on the sol-gel synthesis of cobalt oxide in four different ionic liquids with two different cations and anions. The employed ionic liquids are; 1-ethyl-3-methylimidazolium trifluoromethylsulfonate ([EMIm]TfO), 1-butyl-1-methylpyrrolidinium trifluoromethylsulfonate ([Py1,4]TfO), 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)amide ([EMIm]TFSA), and 1-butyl-1-methylpyrrolidiniumbis(trifluoromethylsulfonyl)amide ([Py1,4]TFSA). The influence of the cation and anion of the ionic liquids on the morphology of the synthesized oxides was explored. The results showed that octahydron-shaped Co3O4 nanoparticles with different average sizes depending on the type of the employed ionic liquid. The imidazolium cation was found to play a significant role in reducing the particle size of the synthesized Co3O4 nanoparticles. The samples prepared in the imidazolium-based ionic liquids showed smaller particle sizes than those of the samples prepared in the pyrrolidinium-based ionic liquids. The shape of the particles of the synthesized Co3O4 was not affected by the type of the ionic liquids.Graphical abstractSEM images of sol-gel synthesized cobalt oxide obtained from the ionic liquids [EMIm]TFSA, [EMIm]TfO, [Py1,4]TFSA and [Py1,4]TfO, and calcined at 500 °C.

Enhanced membraneless fuel cells by electrooxidation of ethylene glycol with a nanostructured cobalt metal catalyst

The advancement of effective and long-lasting electrocatalysts for energy storage devices is crucial to reduce the impact of the energy crisis. In this study, a two-stage reduction process was used to synthesize carbon-supported cobalt alloy nanocatalysts with varying atomic ratios of cobalt, nickel and iron. The formed alloy nanocatalysts were investigated using energy-dispersive X-ray spectroscopy, X-ray diffraction, and transmission electron microscopy to determine their physicochemical characterization. According to XRD results, Cobalt-based alloy nanocatalysts form a face-centered cubic solid solution pattern, illustrating thoroughly mixed ternary metal solid solutions. Transmission electron micrographs also demonstrated that samples of carbon-based cobalt alloys displayed homogeneous dispersion at particle sizes ranging from 18 to 37 nm. Measurements of cyclic voltammetry, linear sweep voltammetry, and chronoamperometry revealed that iron alloy samples exhibited much greater electrochemical activity than non-iron alloy samples. The alloy nanocatalysts were evaluated as anodes for the electrooxidation of ethylene glycol in a single membraneless fuel cell to assess their robustness and efficiency at ambient temperature. Remarkably, in line with the results of cyclic voltammetry and chronoamperometry, the single-cell test showed that the ternary anode works better than its counterparts. The significantly higher electrochemical activity was observed for alloy nanocatalysts containing iron than for non-iron alloy catalysts. Iron stimulates nickel sites to oxidize cobalt to cobalt oxyhydroxides at lower over-potentials, which contributes to the improved performance of ternary alloy catalysts containing iron.

Understanding magnetic interactions and reversal mechanisms in a spinodally decomposed cobalt ferrite using first order reversal curves

Cobalt ferrites exhibit widely varied magnetic behaviour due to the presence of a miscibility gap leading to the formation of periodic self-assembled nanostructures via spinodal decomposition. Periodicity and amplitude of the compositional fluctuations can be controlled by thermodynamic and kinetic processing parameters which allows for careful tuning of the magnetic properties. Although reports have shown evidence of spinodal decomposition, there is a lack of detailed characterization of the magnetic interactions and reversal mechanisms in these materials. In this work we use high-resolution first order reversal curves (FORC) measurements to understand the underlying magnetic processes occurring in a cobalt ferrite with a nominal composition of Co1.8Fe1.2O4 before (calcined) and after spinodal decomposition (annealed). Additionally, FORC measurements with preconditioning fields were conducted to separate the interaction signatures at low coercive fields by biasing the sample in positive and negative mean fields. Microstructural characterization using TEM combined with EDS showed uniform chemistry in the calcined sample and the presence of Fe rich and Co rich regions in the annealed sample, due to spinodal decomposition. Signs of positive exchange interactions were observed in both calcined and annealed samples. This work presents the first detailed magnetic characterization of magnetic interactions in a nanostructured cobalt ferrite, and provides an example of magnetic characterization of nanostructured ferrites using FORC.

Development of a General and Selective Nanostructured Cobalt Catalyst for the Hydrogenation of Benzofurans, Indoles and Benzothiophenes

AbstractThe selective hydrogenation of benzofurans in the presence of a heterogeneous non‐noble metal catalyst is reported. The developed optimal catalytic material consists of cobalt‐cobalt oxide core–shell nanoparticles supported on silica, which has been prepared by the immobilization and pyrolysis of cobalt‐DABCO‐citric acid complex on silica under argon at 800 °C. This novel catalyst allows for the selective hydrogenation of simple and functionalized benzofurans to 2,3‐dihydrobenzofurans as well as related heterocycles. The versatility of the reported protocol is showcased by the reduction of selected drugs and deuteration of heterocycles. Further, the stability, recycling, and reusability of the Co‐nanocatalyst are demonstrated.

Development of a general and selective nanostructured cobalt catalyst for the hydrogenation of benzofurans, indoles and benzothiophenes.

The first selective hydrogenation of benzofurans in the presence of a heterogeneous non-noble metal catalyst is reported. The developed optimal catalytic material consists of cobalt-cobalt oxide core-shell nanoparticles supported on silica, which has been prepared by the immobilization and pyrolysis of cobalt-DABCO-citric acid complex on silica under argon at 800 °C. This novel catalyst allows for the selective hydrogenation of simple and functionalized benzofurans to 2,3-dihydrobenzofurans as well as related heterocycles. The versatility of the reported protocol is showcased by the reduction of selected drugs and deuteration of heterocycles. Further, the stability, recycling, and reusability of the Co-nanocatalyst are demonstrated.