Dispersed Cobalt Research Articles

Oxygen Reduction Reaction Catalysts for Zinc-Air Batteries Featuring Single Cobalt Atoms in a Nitrogen-Doped 3D-Interconnected Porous Graphene Framework.

Single-atom catalysts (SACs) with high activity and efficient atom utilization for oxygen reduction reactions (ORRs) are imperative for rechargeable Zinc-air batteries (ZABs). However, it is still a prominent challenge to construct a noble-metal-free SAC with low cost but high efficiency. Herein, a novel nitrogen-doped graphene (NrGO) based SAC, immobilized with atomically dispersed single cobalt (Co) atoms (Co-NrGO-SAC), is reported for ORRs. In this 3D NrGO, the Co-N4 sites endow high-efficiency ORR activity, and the 3D-interconnected porous architectures of NrGOs guarantee numberous active sites accessibility. Compared to commercial Pt/C catalyst (≈5.8mA cm-2), as-prepared Co-NrGO-SACs presents considerable limiting current density of ≈5.9mA cm-2, prominent half-wave potential of ≈0.84V, onset potential of ≈1.05V, and as well as superior methanol resistance. Particularly, ZABs with Co-NrGO-SACs deliver remarkable power density (≈240mW cm-2), super durability of over 233h at 5mA cm-2, outperforming noble-metal-based benchmarks. This work provides an effective noble-metal free carbon-based SAC nano-engineering for superdurable ZABs.

Salt template-assisted polymer tethering strategy to achieve high dispersed cobalt single atoms/clusters on porous carbon catalysts for effective Fenton-like reactions

The exploration of the synthesis of porous carbon-supported metal nanocatalysts with high metal loading and dispersion for the development of heterogenous catalysts is important. However, this remains a challenging subject. In this paper, a salt template-assisted polymer tethering strategy was proposed to prepare Co single atom and ultrafine cluster anchored on porous carbon (Co-NPC) with a high-loading of 16.9wt%, thereby exposing high density of reaction sites. The obtained Co-NPC catalyst exhibited excellent catalytic performance for almost 100% degradation of bisphenol A (BPA) within 20min, which is much faster than the CoSA-NPC catalyst with only single atom sites and Co-NC without salt template added. Radical quenching experiments and electron paramagnetic resonance tests verified that both the nonradical oxidation pathway by 1O2, the electron transfer and radical oxidation pathway by •OH, SO4•- appeared during the degradation process. After 3 cycles, the removal rate of BPA did not decrease significantly. The fixed bed experiment revealed that Co-NPC could realize the continuous degradation of methylene blue (MB) with almost 100% degradation efficiency. This research indicated that the strategy by pyrolyzing metal coordinated polymer is a potential method for the synthesis of high metal loading catalyst at gram scale, meeting the requirement of practical applications.

Tracing the Structure-Activity Correlation in Cobalt-Doped Heteroatom-Enriched Nanoporous Material for CO2 Electroreduction

The electrochemical CO2 reduction reaction (CO2RR) to value added chemicals (CO, HCOOH, CH4, CH3OH, C2H5OH etc.) utilizing renewable energy sources has attracted considerable attention to close carbon cycle. [1,2] It has several advantages over other approaches such as 1) CO2 could be reduced under mild temperature and pressure conditions, 2) process could be controlled by adjusting the various reaction parameters such as potential etc., and 3) process is compact and feasible for scale up application. [1-3] However, this process has some limitations such as high overpotential, low selectivity & faradaic efficiency for products. Therefore, the designing of highly active electrocatalysts is required to improve catalytic efficiency. Among various reported catalysts, cobalt doped nitrogen enriched materials with atomically dispersed Co–N sites have displayed superior activities and selectivity in electrochemical process for the reduction of CO2. [1-4] However, the effect of synthesis conditions and composition of active species on product selectivity is not rigorously studied yet.In this research, a series of Co-doped multifunctional nitrogen-enriched nanoporous polymer (n-Co@MNENP) with amine and hydroxyl functionalities has been synthesized by condensation of 2-hydroxy-1,3,5-benzenetricarbaldehyde and melamine with calculated amount of cobalt chloride hexahydrate for incorporating n% (n = 10, 50 and 100) of Co content followed by pyrolysis at temperature 550 (designated as n-Co@MNENP-550) and 700 °C (designated as n-Co@MNENP-700). The structure of the synthesized in-situ and pyrolyzed specimens was confirmed by spectroscopic investigations such as FT-IR, and XPS. The Co content was estimated from ICP analysis. The thermal stability of the specimen was investigated using TGA/DTG. The FE-SEM and EDAX revealed almost spherical agglomerated nanoparticles with homogeneous distribution of Co species. PDF and total scattering (TS) analysis confirmed the presence of Co-N species in 10% and 100% samples while 50% sample has metallic Co(fcc/hcp) and CoO/N active species. Further, synthesized specimens have been explored for CO2RR. Among all the electrocatalysts, n-Co@MNENP-700 have shown the higher activity in CO2RR in which 10-Co@MNENP-700 and 100-Co@MNENP-700 could only produce CO, while 50-Co@MNENP-700 results in CO and C2H5OH production. These results reveal that atomically dispersed cobalt–nitrogen sites are responsible for CO generation while CoO, metallic Co species in combination with Co-N sites are responsible for CO and C2H5OH generation which confirmed that the compositions of Co-based catalysts greatly influence CO2RR activity and selectivity.

Ammonia Decomposition via MOF-Derived Photothermal Catalysts.

Three cobalt-based metal-organic framework (MOF)-derived catalysts were developed for photothermal hydrogen production via ammonia decomposition. The selected MOFs were from distinct families, featuring carboxylate and imidazole linkers, and diverse in terms of porosity. The resulting catalysts consisted of uniform and homogeneously dispersed cobalt nanoparticles embedded within a carbon matrix. The carboxylate-based MOF-74 derived catalyst showed the highest initial activity, but gradually deactivated. ZIF-67 derived catalyst, however, demonstrated stable performance. The synergy between photo and thermal effects was confirmed. Additionally, this catalyst was found to be also effective in ammonia synthesis, potentially closing the loop for sustainable ammonia utilization.

Near-Unity Photothermal CO2 Hydrogenation to Methanol Based on a Molecule/Nanocarbon Hybrid Catalyst.

Solar-driven CO2-to-methanol conversion provides an intriguing route for both solar energy storage and CO2 mitigation. For scalable applications, near-unity methanol selectivity is highly desirable to reduce the energy and cost endowed by low-value byproducts and complex separation processes, but so far has not been achieved. Here we demonstrate a molecule/nanocarbon hybrid catalyst composed of carbon nanotube-supported molecularly dispersed cobalt phthalocyanine (CoPc/CNT), which synergistically integrates high photothermal conversion capability for affording an optimal reaction temperature with homogeneous and intrinsically-efficient active sites, to achieve a catalytic activity of 2.4 mmol gcat -1 h-1 and selectivity of ~99 % in direct photothermal CO2 hydrogenation to methanol reaction. Both theoretical calculations and operando characterizations consistently confirm that the unique electronic structure of CoPc and appropriate reaction temperature cooperatively enable a thermodynamic favorable reaction pathway for highly selective methanol production. This work represents an important milestone towards the development of advanced photothermal catalysts for scalable and cost-effective CO2 hydrogenation.

Optimizing Materials to Boost the Valorization of CO2: Tuning Cobalt-Cobalt Interactions on In2O3-Based Photothermal Catalysts.

The valorization of CO2 is an important challenge within the current panorama, since this molecule is probably the main contributor to climate change. In this study, the synthesis of materials based on a nanostructured batonnet-type indium oxide is carried out. In them, different amounts of Co are introduced, varying between 2 and 8% mol. It is verified that the most active sample in the transformation of carbon dioxide to carbon monoxide contains 6 mol %. of Co. This sample's activity under dual excitation exceeds the thermal counterpart by more than 30%. After carrying out a complete physical and chemical characterization with the help of X-ray absorption spectroscopy and other techniques, it is shown that catalysts with amounts of cobalt equal to or below 4 mol % contain isolated single-atom species, while those with higher amounts of metal display a Co-Co interaction which triggers the evolution of the samples under reaction conditions. The optimum control of this Co-Co interaction and the nature of the final cobalt-containing species determine dual photothermal catalytic properties. This work establishes a structure-activity relationship to interpret the catalytic behavior of highly dispersed subnanometric cobalt species, and thus an avenue to optimize the photothermal valorization of carbon dioxide.

Fabrication of polyoxometalate dispersed cobalt oxide nanowires for electrochemically monitoring superoxide radicals from Hela cell mitochondria

An ultrasensitive electrochemical sensor is constructed by electrostatically adsorbing negatively charged hourglass-shape Cu-Polyoxometalate (POM) onto a positively charged CoO nanowires modified carbon cloth. The petaloid CoO nanowires have a large specific surface area that can well disperse open-structured Cu-POM to form Cu-POM@CoONWs@CC, which can maximumly expose catalytic active centers (Co2+ and Cu2+) and accelerate mass/charge transfer. In addition to the above advantages, the excellent electron exchange ability of Cu-POM and good conductivity of CoONWs@CC endow the sensor with good detection capability to H2O2 including a linear detection range of 0.05–1.4 μA μM−1, a low detection limit of 0.022 μM, high sensitivity of 110.48 μA μM−1, good selectivity and long-term stability. Due to the fast transformation of superoxide anion (O2∙‐) to H2O2, the sensor can indirectly monitor the electron leakage resulting in the formation of O2∙‐ via detecting H2O2. Afterwards, Hela cell mitochondria were extracted from the living cells that cultured with different mitochondrial inhibitors and the release of O2∙‐ from the corresponding mitochondrial complexes was monitored by the sensor. Through comparing the current signals, we determined that complex I is probably the main electron leakage site. This work could provide meaningful information for the diagnosis of certain oxidative stress diseases.

Exploring the Impact of Oxygen Vacancies in Co/Pr-CeO2 Catalysts on H2 Production via the Water-Gas Shift Reaction.

In this study, we utilized various Pr-doped CeO2 catalysts (Pr=5, 10, 20, and 30 wt.%) as a support medium for the dispersion of cobalt (Co) nanoparticles, aiming to investigate the impact of oxygen vacancies on the water-gas shift (WGS) reaction. Different characterization techniques were employed to understand the insights into the structure-activity relationship governing the performance of Pr doped ceria supported Co catalysts towards WGS reaction. Our findings reveal that Co/Pr-CeO2 catalysts at optimum Pr loading (10 wt.%) exhibit a superior CO conversion (88 %) facilitated by the presence of more oxygen vacancies induced by Pr doping into the CeO2 lattice, as opposed to the performance of the pure Co/CeO2 catalytic system. It was also found that the highest activity was obtained at increased intrinsic oxygen vacancies and strong synergy between Co and Pr/CeO2 support, fostering more favorable CO activation at the interfacial sites, thus accounting for the observed enhanced activity.

Improved photocatalytic performance of cobalt doped ZnS decorated with graphene nanostructures under ultraviolet and visible light for efficient hydrogen production

Highly dispersed Cobalt doped ZnS nanostructures were successfully fabricated on the surfaces of graphene sheets via a simple hydrothermal method. X-ray diffraction (XRD), X-ray photocurrent spectroscopy (XPS), Raman spectroscopy (RS), Fourier transform infrared spectroscopy (FTIR) and Scanning electron microscopy (SEM) were utilized to analyze the structural characteristics of the cobalt doped ZnS decorated with graphene CoxZn1-xS\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\rm Co}_x{\\rm Zn}_{1-x}{\\rm S}$$\\end{document} rGO nanostructures (NSs). UV-visible optical absorption (UV-vis) studies were conducted to investigate their optical properties. In laboratory studies utilizing water and visible light, the photocatalytic activity of CoxZn1-xS\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\rm Co}_x{\\rm Zn}_{1-x}S$$\\end{document}rGO NSs at (x = 0, 1, 2, 4 and 6 atm.%) were evaluated. Graphite Oxide (GO) was successfully transformed into sheets of graphene and CoxZn1-xSrGO\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\rm Co}_x{\\rm Zn}_{1-x}{\\rm S \\, rGO}$$\\end{document} NSs possessed a crystalline structure according to the findings of XRD, RS and FTIR analysis. SEM investigation showed graphene sheets enhanced with ZnS NSs possessed cuboidal, spheroidal form of structure and displayed a paper like appearance. UV-vis confirmed a noticeable rapid increase in transmittance along the UV wavelength area and confirmed a highly transparent NSs in the wavelength range of (180-800 nm). Calculations using density functional theory (DFT) revealed that the Co NSs have more negative conduction bands than ZnS, allowing for effective electron transfer from cobalt to ZnS and exhibiting a band gap decrease as Co content increased. The Co0.04Zn0.96S\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\rm Co}_{0.04}{\\rm Zn}_{0.96}S$$\\end{document} rGO NSs sample had the highest photocatalytic activity, measured at 7648.9μmolh-1\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$7648.9 \\, \\upmu {\\rm mol} \\, {\\rm h}^{-1}$$\\end{document}. A combination of improved dispersion properties, greater surface area, increased absorption and enhanced transfer of photogenerated electrons, CoxZn1-xS\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${\\rm Co}_x{\\rm Zn}_{1-x}S$$\\end{document} rGO NSs increased the photocatalytic hydrogen generation activity.

Substrate-Assisted Atomic Dispersion of Cobalt for Alkaline Water Electrolysis.

Atomically dispersed single-atom catalysts have recently attracted broad research interest due to their high atom efficiency and unique catalytic performance. In this study, atomic dispersion of cobalt is achieved using a chemical bath deposition method on a highly stable alkali titanate film (Ti/KTiO). These films were characterized using a variety of techniques, with atomic dispersion confirmed via grazing incidence X-ray absorption spectroscopy and ab initio modeling of single-atom systems. This modeling indicated that the alkali ion incorporated into the film facilitates atomic dispersion. Experimentally, the Ti/KTiO-supported Co(OH)2 catalysts exhibited remarkable electrochemical performance, with an overpotential of 163 mV to achieve a current density of 10 mA cm-2 with a catalyst loading of ∼0.1 mg cm-2 and high stability. These results show the potential of Ti/KTiO/Co(OH)2 catalysts for atomically efficient hydrogen production.

Unlocking solid waste utilization: Fly ash-supported cobalt catalyzed transformation of 5-hydroxymethylfurfural into biofuel 2,5-dimethylfuran

5-Hydroxymethylfurfural is a crucial platform molecule derived from biomass, and its selective conversion to furan chemicals holds significant importance for the high-value utilization of biomass. In this study, acid-modified coal fly ash was used as a support for non-precious metal cobalt to prepare a novel catalyst (Co/CFA), which demonstrated excellent performance in the selective hydrodeoxygenation of 5-hydroxymethylfurfural to 2,5-dimethylfuran. By investigating the catalyst preparation conditions, it was found that with a 30wt% cobalt loading, the selectivity of 2,5-dimethylfuran can reach 98.1 %, and the conversion of 5-hydroxymethylfurfural is 99.0 %. A series of characterization showed that the acid modification treatment increased the pore structure and specific surface area of the coal fly ash, was conducive to the dispersion of cobalt, and improved the activity of the Co/CFA catalyst. This innovative approach harnesses the potential of waste materials, emphasizing resource efficiency and sustainability in catalyst development.

Oxidative Upcycling of Polyethylene to Long Chain Diacid over Co‐MCM‐41 Catalyst

AbstractPlastic pollution is an emerging global threat due to lack of effective methods for transforming waste plastics into useful resources. Here, we demonstrate a direct oxidative upcycling of polyethylene into high‐value and high‐volume saturated dicarboxylic acids in high carbon yield of 85.9 % in which the carbon yield of long chain dicarboxylic (C10‐C20) acids can reach 58.9% over cobalt‐doped MCM‐41 molecular sieves, in the absence of any solvent or precious metal catalyst. The distribution of the dicarboxylic acids can be controllably adjusted from short‐chain (C4‐C10) to long‐chain ones (C10‐C20) through changing cobalt loading of MCM‐41 under nanoconfinement. Highly and sparsely dispersed cobalt along with confined space of mesoporous structure enables complete degradation of polyethylene and high selectivity of dicarboxylic acid in mild condition. So far, this is the first report on highly selective one‐step preparation of long chain dicarboxylic acids. The approach provides an attractive solution to tackle plastic pollution and a promising alternative route to long chain diacids.

The solvation environment of molecularly dispersed cobalt phthalocyanine determines methanol selectivity during electrocatalytic CO2 reduction

The solvation environment of molecularly dispersed cobalt phthalocyanine determines methanol selectivity during electrocatalytic CO2 reduction

Elucidating the role of embedding dispersed cobalt sites in nitrogen-doped carbon frameworks in Si-based anodes for stable and superior storage

Unsatisfactory conductivity and volume effects have hindered the commercial application of silicon-based materials as advanced anode materials for high-performance lithium-ion batteries. Herein, nitrogen doped carbon silicon matrix composite with atomically dispersed Co sites (Si/Co-N-C) is obtained via the design of the frame structure loaded with nano-components and the multi-element hybrid strategy. Co atoms are uniformly fixed to the N-C frame and tightly packed with nanoscale silicon particles as an activation and protection building block. The mechanism of the N-C framework of loaded metal Co in the Si alloying process is revealed by electrochemical kinetic analysis and ex situ characterization tests. Impressively, the nitrogen-doped Co site activates the intercalation of the outer carbon matrix to supplement the additional capacity. The Co nanoparticles with high conductivity and support enhance the conductivity and structural stability of the composite, accelerating the Li+/Na+ diffusion kinetics. Density functional theory (DFT) calculation confirms that the hetero-structure Si/Co-N-C adjusts the electronic structure to obtain good lithium-ion adsorption energy, reduces the Li+/Na+ migration energy barrier. This work provides meaningful guidance for the development of high-performance metal/non-metal modified anode materials.

Furfural Hydrogenation Over Reduced Pure (LaBO3) and Substituted (LaB0.5B'0.5O3) (B, B': Fe, Co, Ni) Perovskites

AbstractA series of pure and 50 % substituted Fe‐containing (LaFeO3, LaFe0.5Ni0.5O3 and LaFe0.5Co0.5O3) and Co/Ni‐containing (LaCoO3, LaNiO3, and LaCo0.5Ni0.5O3) perovskites were used as precursors to synthesize metallic reduced catalysts to be tested for the liquid hydrogenation of furfural. The catalytic reaction was carried out in a batch reactor at 200 °C and 3.0 MPa of H2 pressure. The calcined perovskites and reduced catalysts were characterized by X‐ray diffraction (XRD), N2 physisorption at 77 K, temperature programmed reduction (H2‐TPR), temperature programmed CO2 and NH3 desorption (CO2‐TPD and NH3‐TPD), Atomic Absorption Spectroscopy (AAS) and X‐ray photoelectron spectroscopy (XPS) techniques. The LaCo0.5Ni0.5O3 reduced catalyst display the highest activity in furfural conversion, which was attributed to a cooperative effect between highly dispersed nickel and cobalt metal nanoparticles after reduction process. The effect of the nature of B‐cation have a high impact on the products selectivity in the hydrogenation of furfural, suggesting that enriched‐Ni metal surface was selectivity to tetrahydrofurfuryl alcohol, meanwhile enriched‐Co metal surface was selective to furfuryl alcohol formation, which was also supported with adsorption mode of furfural over the active sites obtained by quantum calculation.

Pomelo peel biomass derived highly active advanced-oxidation-process catalyst: Complete elimination of organic pollutants

The advanced oxidation process (AOPs) is playing an important role in the elimination of hazardous organic pollutants, but the development of inexpensive and highly active advanced catalysts is facing challenges. In this study, a low-cost and readily available agricultural waste resource pomelo peel-flesh (PPF) biomass was used as the basic raw material, and the uniformly dispersed small cobalt nanoparticles were effectively anchored in the biochar derived from pomelo peel-flesh (BDPPF) by impregnation adsorption/complexation combined with heat treatment. Co/BDPPF (BDPPF embedded with Co) can effectively activate peroxymonosulfate (PMS) to SO4·-, ·OH and 1O2 reactive oxygen species, and achieve nearly 100% degradation of tetracycline persistent organic pollutant. Co/BDPPF can not only degrade tetracycline efficiently in complex water environment, but also degrade most organic pollutants universally, and has long-term stability, which solves the problem of poor universality and stability of heterogeneous catalysts to a certain extent. Importantly, Co/BDPPF derived from waste biomass was also innovatively designed as the core of an integrated continuous purification device to achieve continuous purification of organic wastewater. In this study, agricultural waste resources were selected as biomass raw materials to achieve efficient capture of Co2+, and finally developed advanced AOPs catalyst with excellent performance to achieve the purification of organic wastewater. It also provides a promising solution for the preparation of simple, low-cost, large-scale production of AOPs catalysts that can be put into actual production.

Highly dispersed cobalt clusters/nanoparticles embedded in cellulose nanocrystal derived carbon aerogel as efficient sulfur host for high performance lithium sulfur batteries

Exploring multifunctional sulfur host materials with high immobilization ability and catalytic activity is of great significance for realizing high-performance Lithium-sulfur (Li–S) batteries. Recently, cellulose nanocrystals (CNCs) receive extensive attention for advanced energy storage applications owing to their intrinsically exceptional physical/chemical properties and natural abundance. Herein, a highly dispersed cobalt clusters/nanoparticles embedded into CNC derived carbon aerogel composite (CA/Co-2) is for the first time synthesized. Benefiting from the interconnected hierarchical porous structure, homogeneously anchored Co clusters/nanoparticles and N-doped species, the designed CA/Co-2 could enable rapid electron/ion transport, efficient sulfur utilization, effective suppression of the shuttle effect and fast catalytic conversion of polysulfides, thereby contributing to outstanding electrochemical performance. Consequently, CA/Co-2@S cathode delivers high initial discharge capacity (1553.1 mAh g−1 at 0.1C) and superior cycle stability. Moreover, a remarkable rate performance of 681.4 mAh g−1 at 5.0C and exceptional long-term cycling stability with an ultralow capacity decay of 0.028 % per cycle at 5.0C over 1000 cycles could be achieved when coupled with carbon paper interlayer. This work develops a workable strategy for fabricating multifunctional sulfur host derived from the fascinating bio-nanomaterial of CNC, which provides valuable guidance for the future design of high-performance Li–S batteries.

Synergistic role of Co and CoP on highly dispersed cobalt nanoparticles embeded in porous carbon for efficient PH3 decomposition

Efficient resourceful treatment of phosphine tail gas is a huge challenge. In this study, a series of cobalt nanoparticles embeded in porous carbon (Co@C) catalysts were obtained via pyrolysis of Co-based MOF as precursor for catalytic decomposition of phosphine (PH3) by regulating the ratio of reactants of MOFs. The composition, morphology and structure of the catalysts were characterized by inductively coupled plasma, X-ray diffraction, scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy and BET measurement. The effect of Co@C catalysts with different reactant ratio on the catalytic decomposition of PH3 was tested, and the catalysts before and after the reaction were compared. It was found that the catalyst with MOF as the precursor after pyrolysis can still retain the porosity and large specific surface area of MOF. The metal cobalt nanoparticles and its oxides can be uniformly distributed in time under high loading, which is conducive to the reaction with phosphine to form metal phosphide (CoP), and the rapid and efficient decomposition of PH3 was completed under the synergistic effect of the two kinds of active sites of Co and CoP. The best catalytic decomposition efficiency is Co@C-5 catalyst, which can achieve 100 % decomposition efficiency at 350 °C and has good stability.

Influence of the type of support on the physicochemical properties of cobalt catalysts

The article presents the results of studies of the physicochemical properties of cobalt catalysts on a zeolite support. For research, BET methods were used. The nature of the influence of the nature of the support on the structural (specific surface area, dispersion of metal cobalt, size of metal crystallites) and chemical (degree of cobalt reduction) properties of catalysts has been established.

Multicomponent Reductive Coupling for Selective Access to Functional γ-Lactams by a Single-Atom Cobalt Catalyst.

Despite their significant importance to numerous fields, the difficulties in direct and diverse synthesis of α-hydroxy-γ-lactams pose substantial obstacles to their practical applications. Here, we designed a nitrogen and TiO2 co-doped graphitic carbon-supported material with atomically dispersed cobalt sites (CoSA-N/NC-TiO2), which was successfully applied as a multifunctional catalyst to establish a general method for direct construction of α-hydroxy-γ-lactams from cheap and abundant nitro(hetero)arenes, aldehydes, and H2O with alkynoates. The striking features of operational simplicity, broad substrate and functionality compatibility (>100 examples), high step and atom efficiency, good selectivity, and exceptional catalyst reusability highlight the practicality of this new catalytic transformation. Mechanistic studies reveal that the active CoN4 species and the dopants exhibit a synergistic effect on the formation of key acid-masked nitrones; their subsequent nucleophilic addition to the alkynoates followed by successive reduction, alkenyl hydration, and intramolecular ester ammonolysis delivers the desired products. In this work, the concept of reduction interruption leading to new reaction route will open a door to further develop useful transformations by rational catalyst design.