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Facile and large‐scale production of Ag nanoparticles for selective electrochemical
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reduction reaction. B KOREAN CHEM SOC 2021. [DOI: 10.1002/bkcs.12393] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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ZHELTONOZHSKAYA Т, PERMYAKOVA N, FOMENKO A, KUNITSKAYA L, KLEPKO V, GRISHCHENKO L, KLYMCHUK D. FORMATION OF NICKEL NANOPARTICLES IN SOLUTIONS OF A HYDROPHILIC GRAFT COPOLYMER. Polym J 2021. [DOI: 10.15407/polymerj.43.02.079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A graft copolymer of poly(vinyl alcohol) and polyacrylamide (PVA-g-PAAm) with interacting main and grafted chains was synthesized by radical matrix polymerization of PAAm from the PVA backbone in an aqueous medium. Its basic molecular parameters including the number and length (molecular weight) of grafts were determined using elemental analysis, DTGA and viscometry. The copolymer macromolecules formed special monomolecular micelles of elipsoidal shape and length ~18-64 nm in aqueous solutions due to the formation of intramolecular polycomplexes between the main and grafted chains. This copolymer was used as a hydrophilic matrix for the in situ synthesis of nickel nanoparticles (NiNPs) in aqueous solutions.On the basis of UV-Vis spectroscopy, an original and simple method for monitoring the kinetics of the formation and yield of metal nanoparticles in systems in which a surface plasmon resonance band does not appear has been proposed and implemented. Using this approach, the kinetics of borohydride reduction of Ni-salt to NiNPs in pure water and PVA-g-PAAm solutions was studied depending on the concentrations of Ni-salt and copolymer matrices. An increase in the initial rate of accumulation and yield of NiNPs with an increase in the concentration of Ni-salt and a decrease in both parameters in copolymer solutions in comparison with pure water was established. At the same time, the accumulation rate and NiNP yield in a complex way was depended on the matrix concentration that was determined by the ratio of such factors as a decrease in the diffusion rate of NaBH4 molecules in copolymer solutions and the accumulation of Ni2+-ions in matrix particles due to complexation with active chemical groups at the first stage of reduction process. The morphology and main structural elements of the NiNPs/PVA-g-PAAm composition were revealed using TEM. It was shown that the in situ synthesis of NiNPs in copolymer matrices was accompanied by the “detachment” of PAAm grafts from the main PVA chains and led to the appearance of two new structures, such as “hairy coils” and “hairy rods”, containing small spherical NiNPs (d~0,5–12,0 nm) in isolated and chain states, respectively. The appearance of the latter structures was explained by the formation of coordination complexes of Ni2+-ions with active groups of both PVA and PAAm chains at the first stage of the reduction reaction.
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Kim T, Paul B, Kwon D, Nam SC, Jo C. Nickel Nanoparticles Supported on Nonreducible Mesoporous Materials: Effects of Framework Types on the Catalytic Decomposition of Methane. B KOREAN CHEM SOC 2020. [DOI: 10.1002/bkcs.12168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Taeho Kim
- Department of Chemistry and Chemical Engineering Inha University 100 Inha‐ro, Incheon 22212 South Korea
| | - Bappi Paul
- Department of Chemistry and Chemical Engineering Inha University 100 Inha‐ro, Incheon 22212 South Korea
| | - Dong‐il Kwon
- Department of Chemistry and Chemical Engineering Inha University 100 Inha‐ro, Incheon 22212 South Korea
| | - Sung Chan Nam
- Greenhouse Gas Laboratory Korea Institute of Energy Research 217 Gajeong‐ro, Daejeon 34129 South Korea
| | - Changbum Jo
- Department of Chemistry and Chemical Engineering Inha University 100 Inha‐ro, Incheon 22212 South Korea
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Potential Liquid-Organic Hydrogen Carrier (LOHC) Systems: A Review on Recent Progress. ENERGIES 2020. [DOI: 10.3390/en13226040] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The depletion of fossil fuels and rising global warming challenges encourage to find safe and viable energy storage and delivery technologies. Hydrogen is a clean, efficient energy carrier in various mobile fuel-cell applications and owned no adverse effects on the environment and human health. However, hydrogen storage is considered a bottleneck problem for the progress of the hydrogen economy. Liquid-organic hydrogen carriers (LOHCs) are organic substances in liquid or semi-solid states that store hydrogen by catalytic hydrogenation and dehydrogenation processes over multiple cycles and may support a future hydrogen economy. Remarkably, hydrogen storage in LOHC systems has attracted dramatically more attention than conventional storage systems, such as high-pressure compression, liquefaction, and absorption/adsorption techniques. Potential LOHC media must provide fully reversible hydrogen storage via catalytic processes, thermal stability, low melting points, favorable hydrogenation thermodynamics and kinetics, large-scale availability, and compatibility with current fuel energy infrastructure to practically employ these molecules in various applications. In this review, we present various considerable aspects for the development of ideal LOHC systems. We highlight the recent progress of LOHC candidates and their catalytic approach, as well as briefly discuss the theoretical insights for understanding the reaction mechanism.
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