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Chandra D, Saini S, Bhattacharya S, Bhaumik A, Kamata K, Hara M. Electronic Effect in a Ruthenium Catalyst Designed in Nanoporous N-Functionalized Carbon for Efficient Hydrogenation of Heteroarenes. ACS APPLIED MATERIALS & INTERFACES 2020; 12:52668-52677. [PMID: 33185087 DOI: 10.1021/acsami.0c15407] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Active metal catalysts are the key in chemical industry for sustainable production of multitude of chemical resources. Here, we report a new ruthenium (Ru) composite with a synergistically controlled nanostructure and electronic properties as a highly efficient hydrogenation catalyst which comprises stable small Ru nanoparticles (mean particle size, ca. 0.9 nm) in situ generated into a nanoporous N-functionalized carbon with high surface area (ca. 650 m2 g-1) and has strong electron-donating power of Ru sites of nanoparticles. The scalable and highly reusable catalyst, prepared from a self-assembled Ru complex, performs actively with low per metal usage under mild conditions (60-80 °C and 0.5-1.0 MPa H2) for selective hydrogenation of various quinolines and pyridines. The role of electron-donating properties of the new Ru nanohybrid for highly efficient catalysis was characterized by both experiments and computational studies. Density functional theory calculations reveal that weak adsorption energies of quinoline at the electron-rich Ru surface prevents poisoning caused by its strong coordination and provides excellent reusability of the catalyst, while low activation barriers for the hydrogenation steps of the N-heterocyclic ring correlate with high catalytic activity. Our catalyst exhibits 5-24-fold higher turnover frequency up to ca. 167 h-1 among the efficient noble metal catalysts reported for selective hydrogenation of quinoline to 1,2,3,4-tetrahydroquinoline.
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Wendisch F, Abazari M, Werner V, Barb H, Rey M, Goerlitzer ESA, Vogel N, Mahdavi H, Bourret GR. Spatioselective Deposition of Passivating and Electrocatalytic Layers on Silicon Nanowire Arrays. ACS APPLIED MATERIALS & INTERFACES 2020; 12:52581-52587. [PMID: 33169967 PMCID: PMC7705884 DOI: 10.1021/acsami.0c14013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 10/26/2020] [Indexed: 05/21/2023]
Abstract
Metal-silicon nanowire array photoelectrodes provide a promising architecture for water-splitting because they can afford high catalyst loading and decouple charge separation from the light absorption process. To further improve and understand these hybrid nanowire photoelectrodes, control of the catalyst amount and location within the wire array is required. Such a level of control is currently synthetically challenging to achieve. Here, we report the synthesis of cm2-sized hybrid silicon nanowire arrays with electrocatalytically active Ni-Mo and Pt patches placed at defined vertical locations within the individual nanowires. Our method is based on a modified three-dimensional electrochemical axial lithography (3DEAL), which combines metal-assisted chemical etching (MACE) to produce Si nanowires with spatially defined SiO2 protection layers to selectively cover and uncover specific areas within the nanowire arrays. This spatioselective SiO2 passivation yields nanowire arrays with well-defined exposed Si surfaces, with feature sizes down to 100 nm in the axial direction. Subsequent electrodeposition directs the growth of the metal catalysts at the exposed silicon surfaces. As a proof of concept, we report photoelectrocatalytic activity of the deposited catalysts for the hydrogen evolution reaction on p-type Si nanowire photocathodes. This demonstrates the functionality of these hybrid metal/Si nanowire arrays patterned via 3DEAL, which paves the way for investigations of the influence of three-dimensional geometrical parameters on the conversion efficiency of nanostructured photoelectrodes interfaced with metal catalysts.
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Kang JH, Lee J, Jung JW, Park J, Jang T, Kim HS, Nam JS, Lim H, Yoon KR, Ryu WH, Kim ID, Byon HR. Lithium-Air Batteries: Air-Breathing Challenges and Perspective. ACS NANO 2020; 14:14549-14578. [PMID: 33146514 DOI: 10.1021/acsnano.0c07907] [Citation(s) in RCA: 36] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Lithium-oxygen (Li-O2) batteries have been intensively investigated in recent decades for their utilization in electric vehicles. The intrinsic challenges arising from O2 (electro)chemistry have been mitigated by developing various types of catalysts, porous electrode materials, and stable electrolyte solutions. At the next stage, we face the need to reform batteries by substituting pure O2 gas with air from Earth's atmosphere. Thus, the key emerging challenges of Li-air batteries, which are related to the selective filtration of O2 gas from air and the suppression of undesired reactions with other constituents in air, such as N2, water vapor (H2O), and carbon dioxide (CO2), should be properly addressed. In this review, we discuss all key aspects for developing Li-air batteries that are optimized for operating in ambient air and highlight the crucial considerations and perspectives for future air-breathing batteries.
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Xia Q, Jin X, Zhang G, Liu M, Wang J, Li Y, Fang T, Ding J, Zhang D, Meng K, Chen X, Yang C. Catalytic Deoxygenation of Xylitol to Renewable Chemicals: Advances on Catalyst Design and Mechanistic Studies. CHEM REC 2020; 21:133-148. [PMID: 33180367 DOI: 10.1002/tcr.202000101] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Revised: 10/10/2020] [Accepted: 10/13/2020] [Indexed: 11/12/2022]
Abstract
Xylitol is commonly known as one of the top platform intermediates for biomass conversion. Catalytic deoxygenation of xylitol provides an atomic and energetic efficient way to produce a variety of renewable chemicals including ethylene glycol, 1,2-propanediol, lactic acid and 1,4-anhydroxylitol. Despite a few initial attempts in converting xylitol into those products, improving catalyst selectivity towards C-O and C-C cleavage reactions remains a grand challenge in this area. To our best knowledge, there is lack of comprehensive review to summarize the most recent advances on catalyst design and mechanisms in deoxygenation of xylitol, offering important perspective into future development of xylitol transformation technologies. Therefore, in this mini-review, we have critically discussed the conversion routes involved in xylitol deoxygenation over solid catalyst materials, the nanostructures of supported metal catalysts for C-H, C-C and C-O bond cleavage reactions, and mechanistic investigation for xylitol conversion. The outcome of this work provides new insights into rational design of effective deoxygenation catalyst materials for upgrading of xylitol and future process development in converting hemicellulosic biomass.
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Ghazvini M, Sheikholeslami-Farahani F, Shafiee S, Salimifard M, Eslami AA. ZnO-nano catalyst Promoted the Production of Imidazole Derivatives via four-component Reaction of Aminoacid: Study of Antioxidant and Antimicrobial Activity. Comb Chem High Throughput Screen 2020; 24:841-848. [PMID: 33109056 DOI: 10.2174/1386207323999200820163129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2020] [Revised: 06/23/2020] [Accepted: 07/22/2020] [Indexed: 11/22/2022]
Abstract
AIM AND OBJECTIVE In current research, imidazole derivatives are synthesized via a new process of four component reaction of trichloroacetonitrile, amides, alkyl bromides and amino acids catalyzed by zinc oxide nanoparticles (ZnO-NPs) as a simple and recyclable catalyst in water at room temperature. Among investigated compounds, compounds 5b have good results relative to butylated hydroxytoluene (BHT) and 2-tert-butylhydroquinone (TBHQ) as standard antioxidant. The achieved outcomes of disk diffusion experiment showed that these compounds avoided the growth of bacterial. MATERIALS AND METHODS In this research, all chemicals are purchased from Fluka (Buchs, Switzerland) and employed with any purification. For measuring infrared spectroscopy and melting point, a Shimadzu IR-460 spectrometer and Electrothermal 9100 apparatus are utilized respectively. BRUKER DRX-400 AVANCE spectrometer is used for giving the 1H, and 13CNMR spectra at 400.1 and 100 MHz respectively. For recording mass spectra, A FINNIGAN-MAT 8430 spectrometer with an ionization potential of 70 eV was utilized. The scanning electron microscopy (SEM) employing a Holland Philips XL30 microscope was used for determination of ZnO nanocomposites morphology. X-ray diffraction (XRD) analysis at room temperature using a Holland Philips Xpert X-ray powder diffractometer, with CuKα radiation (λ=0.15406 nm), with 2θ ranging from 20 to 80° was employed for characterization of crystalline structure of Fe3O4/CuO nanocomposites. Scherrer's formula; D= 0.9λ/β cosθ was employed for calculating the average crystallite size where D is the diameter of the nanoparticles, λ (CuKα) =1.5406 Å and β is the fullwidth at half-maximum of the diffraction lines. A general way to prepare of compounds 5 The trichloroacetonitrile 1 (2 mmol) and amides 2 (2 mmol) mixed with ZnO-NPs (10 mol%) in water (5 mL). after 45 min amino acids 3 (2 mmol) was added to previous mixture at room temperature. After 30 min α-haloketones 4 (2 mmol) was added to mixture and stirred for 3 h. After 3 h, the reaction is completed and TLC confirms progress of the reaction. At last, the solid residue was collected by filtration and cleaned with EtOAC to removing ZnO-NPs and after evaporating solvent and washing solid with Et2O compounds 5 afforded as pure product. RESULTS Without employing catalyst, these reactions have low yield and busy mixture. The synthesis of compound 5a as sample reaction and displayed the ZnO nanoparticles (10 mol%) is the best catalyst for sample reaction and H2O is the very better than other solvent in sample raection. Structures of 5 are confirmed by IR, 1H NMR, 13C NMR mass spectra. CONCLUSION In summary, imdazole derivatives were produced in excellent yield from the reaction of trichloroacetonitrile, amides, alkyl bromides and amino acids using ZnO-NPs in water at room temperature. In addition, the power of synthesized imidazole as antioxidant was determined by radical trapping of DPPH and power of reducing ferric analyzes. The tested imidazoles display good radical trapping of DPPH but exhibitted moderate FRAP relative to BHT and TBHQ as synthetic antioxidants.The outcomes of disk diffusion experiment exhibite that synthesized imidazole avoided the bacterial growth. The superiorities of this procedure are environmental, high yield of product and low amounts of catalyst and short time of reaction.
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Lv S. Silk Fibroin-Based Materials for Catalyst Immobilization. Molecules 2020; 25:E4929. [PMID: 33114465 PMCID: PMC7663501 DOI: 10.3390/molecules25214929] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Revised: 10/10/2020] [Accepted: 10/20/2020] [Indexed: 11/17/2022] Open
Abstract
Silk fibroin is a widely and commercially available natural protein derived from silkworm cocoons. Thanks to its unique amino acid composition and structure, which lead to localized nanoscale pockets with limited but sufficient hydration for protein interaction and stabilization, silk fibroin has been studied in the field of enzyme immobilization. Results of these studies have demonstrated that silk fibroin offers an important platform for covalent and noncovalent immobilization of enzymes through serving as a stabilization matrix/support with high retention of the biological activity of the enzymes of interest. In the hope of providing suggestions for potential future research directions, this review has been written to briefly introduce and summarize key advances in silk fibroin-based materials for immobilization of both enzymes/biocatalysts (including alkaline phosphatase, β-glucosidase, glucose oxidase, lipase, urease, uricase, horseradish peroxidase, catalase, xanthine oxidase, tyrosinase, acetylcholinesterase, neutral protease, α-chymotrypsin, amylase, organophosphorus hydrolase, β-galactosidase, carbonic anhydrase, laccase, zymolyase, phenylalanine ammonia-lyase, thymidine kinase, and several others) and non-enzymatic catalysts (such as Au, Pd, Fe, α-Fe2O3, Fe3O4, TiO2, Pt, ZnO, CuO, Cu2O, Mn3O4, and MnO2).
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Ahmed F, Kabir H, Xiong H. Dual Colorimetric Sensor for Hg 2+/Pb 2+ and an Efficient Catalyst Based on Silver Nanoparticles Mediating by the Root Extract of Bistorta amplexicaulis. Front Chem 2020; 8:591958. [PMID: 33195096 PMCID: PMC7642621 DOI: 10.3389/fchem.2020.591958] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 09/11/2020] [Indexed: 11/13/2022] Open
Abstract
Environmental pollution derivated from toxic metals and organic toxins is becoming a serious issue worldwide because of their harmful effects on the ecosystem and human health. Here we are reporting an extremely selective and cost-effective colorimetric sensor for simultaneous recognition of Hg2+ and Pb2+ by using green synthesized silver nanoparticles (AgNPs) mediated from the environmental friendly roots extract of Bistorta amplexicaulis. Biogenic synthesized AgNPs were well-characterized by various spectroscopic techniques e.g., UV-vis, FT-IR, XRD, AFM, and Zetasizer. The photophysical potential of synthesized AgNPs toward common metal cations was explored via absorption spectroscopy and colorimetric assay. The hypsochromic shift in the SPR band of AgNPs can easily be detected through naked eyes vision from dark brown to light yellow in the case of Hg2+. A substantial reduction in the absorbance of AgNPs was recorded upon mixing with Pb2+. AgNPs based colorimetric sensor is highly sensitive toward Hg2+ and Pb2+ with a limit of detection (LOD) of 8.0 × 10-7 M and 2.0 × 10-7 M for Hg2+ and Pb2+, respectively. Furthermore, AgNPs showed promising catalytic activity for the degradation of methyl orange dye. These results demonstrate that Bistorta amplexicaulis stabilized silver nanoparticles have potential applications as a colorimetric sensor and an effective catalyst for the degradation of methyl orange.
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Gao H, Shao Y, Shi R, Liu Y, Zhu J, Liu J, Zhu Y, Zhang J, Li L, Hu X. Effect of Few-Layer Ti 3C 2T x Supported Nano-Ni via Self-Assembly Reduction on Hydrogen Storage Performance of MgH 2. ACS APPLIED MATERIALS & INTERFACES 2020; 12:47684-47694. [PMID: 33044811 DOI: 10.1021/acsami.0c15686] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
For the first time, few-layer Ti3C2Tx (FL-Ti3C2Tx) supporting highly dispersed nano-Ni particles with an interconnected and interlaced structure was elaborated through a self-assembly reduction process. FL-Ti3C2Tx not only acts as a supporting material but also self-assembles with Ni2+ ions through the electrostatic interaction, assisting in the reduction of nano-Ni. After ball milling with MgH2, Ni30/FL-Ti3C2Tx (few-layer Ti3C2Tx supported 30 wt % nano-Ni via self-assembly reduction) shows superior catalytic activity for MgH2. For example, MgH2-5 wt % Ni30/FL-Ti3C2Tx can release approximately 5.83 wt % hydrogen within 1800 s at 250 °C and absorb 5 wt % hydrogen within 1700 s at 100 °C. The combined effects of finely dispersed nano-Ni in situ-grown on FL-Ti3C2Tx, large specific area of FL-Ti3C2Tx, multiple-valence Ti (Ti4+, Ti3+, Ti2+, and Ti0) derived from FL-Ti3C2Tx, and the electronic interaction between Ni and FL-Ti3C2Tx can explain the superb hydrogen storage performance. Our results will attract more attention to the elaboration of the metal/FL-Ti3C2Tx composite via self-assembly reduction and provide a guideline to design high-efficiency composite catalysts with MXene in hydrogen storage fields.
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Ptak S, Zarski A, Kapusniak J. The Importance of Ionic Liquids in the Modification of Starch and Processing of Starch-Based Materials. MATERIALS 2020; 13:ma13204479. [PMID: 33050342 PMCID: PMC7601111 DOI: 10.3390/ma13204479] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 10/02/2020] [Accepted: 10/06/2020] [Indexed: 11/16/2022]
Abstract
The main applications of ionic liquids in chemistry and material research on one of the most important natural polymers—starch—are presented in this review. A brief characterization of ionic liquids and the advantages and disadvantages of using them in the modification and processing of polysaccharides is presented. The latest reports on the use of various ionic liquids as solvents or co-solvents; as media for synthesizing starch derivatives in oxidation, etherification, esterification, and transesterification, with particular emphasis on biocatalyzed reactions; and as plasticizers or compatibilizers in the processing of starch-based polymers have been investigated. The current trends, possibilities, and limitations of using this type of compound for the production of functional starch-based materials are presented.
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Ahsan H, Islam SU, Ahmed MB, Lee YS, Sonn JK. Significance of Green Synthetic Chemistry from a Pharmaceutical Perspective. Curr Pharm Des 2020; 26:5767-5782. [PMID: 32988346 DOI: 10.2174/1381612826666200928160851] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 08/10/2020] [Indexed: 11/22/2022]
Abstract
BACKGROUND Conventional practices of synthesis, manufacturing, and processing have led to severe adverse consequences for living beings and the environment. OBJECTIVES Although medications cannot be replaced, the methods of synthesizing, manufacturing, and processing them can be changed and/or replaced. This paper explains the significance of green chemistry practices in the pharmaceutical industry. It emphasizes that we must replace conventional drug synthesis, processing, and manufacturing techniques with greener ones that are cost-effective, sustainable, environment-friendly, and profitable. DISCUSSION This paper comprises five sections. Section 1 is an introduction to green chemistry and its correlation with the pharmaceutical industry. Section 2 discusses the metrics necessary to measure the greenness of a process. Section 3 is about solvents used in the pharmaceutical industry, hazards, safety status, and environmental effects, including the ozone depletion potential. Section 4 explains catalytic amidation reactions because amides are one of the most commonly occurring functional groups with pharmacological activity. Section 5 discusses successful cases of converting conventional synthesis of active pharmaceutical ingredients and/or their intermediates to greener, sustainable alternatives. CONCLUSION A balance is necessary between profits, processes, consumers, and the environment to ensure the survival of all stakeholders and decrease the environmental burden of pharmaceuticals. Incentives such as green chemistry awards should be endorsed and encouraged, in addition to making green chemistry part of tertiary education. In addition, changes to rules and regulations for drug approval in the context of green chemistry principles are necessary in order to preserve our planet for future generations.
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Shetgaonkar SE, Singh FV. Hypervalent Iodine Reagents in Palladium-Catalyzed Oxidative Cross-Coupling Reactions. Front Chem 2020; 8:705. [PMID: 33134246 PMCID: PMC7553084 DOI: 10.3389/fchem.2020.00705] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2020] [Accepted: 07/09/2020] [Indexed: 01/12/2023] Open
Abstract
Hypervalent iodine compounds are valuable and versatile reagents in synthetic organic chemistry, generating a diverse array of useful organic molecules. Owing to their non-toxic and environmentally friendly features, these reagents find potential applications in various oxidative functionalization reactions. In recent years, the use of hypervalent iodine reagents in palladium-catalyzed transformations has been widely studied as they are strong electrophiles and powerful oxidizing agents. For instance, extensive work has been carried out in the field of C–H bond functionalization via Pd-catalysis using hypervalent iodine reagents as oxidants. In addition, nowadays, iodine(III) reagents have been frequently employed as arylating agents in Pd-catalyzed C–H arylation or Heck-type cross-coupling reactions. In this review, recent advancements in the area of palladium-catalyzed oxidative cross-coupling reactions using hypervalent iodine reagents are summarized in detail.
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Vijayakumar A, Zhao Y, Zou J, Wang K, Lee CY, MacFarlane DR, Wang C, Wallace GG. A Self-Assembled CO 2 Reduction Electro catalyst: Posy-Bouquet-Shaped Gold-Polyaniline Core-Shell Nanocomposite. CHEMSUSCHEM 2020; 13:5023-5030. [PMID: 32666707 DOI: 10.1002/cssc.202001248] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2020] [Revised: 06/15/2020] [Indexed: 06/11/2023]
Abstract
Here it was demonstrated that the decoration of gold (Au) with polyaniline is an effective approach in increasing its electrocatalytic reduction of CO2 to CO. The core-shell-structured gold-polyaniline (Au-PANI) nanocomposite delivered a CO2 -to-CO conversion efficiency of 85 % with a high current density of 11.6 mA cm-2 . The polyaniline shell facilitated CO2 adsorption, and the subsequent formation of reaction intermediates on the gold core contributed to the high efficiency observed.
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Thongpitak J, Pumas P, Pumas C. Paraquat Degradation by Biological Manganese Oxide (BioMnO x ) Catalyst Generated From Living Microalga Pediastrum duplex AARL G060. Front Microbiol 2020; 11:575361. [PMID: 33042090 PMCID: PMC7522373 DOI: 10.3389/fmicb.2020.575361] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 08/24/2020] [Indexed: 11/13/2022] Open
Abstract
Paraquat is a non-selective fast-acting herbicide used to control weeds in agricultural crops. Many years of extensive use has caused environmental pollution and food toxicity. This agrochemical degrades slowly in nature, adsorbs onto clay lattices, and may require environmental remediation. Studies have shown that biosynthesized manganese oxide (BioMnOx) successfully degraded toxic synthetic compounds such as bis-phenol A and diclofenac, thus it has potential for paraquat degradation. In this experiment, P. duplex AARL G060 generated low (9.03 mg/L) and high (42.41 mg/L) concentrations of BioMnOx. The precipitated BioMnOx was observed by scanning electron microscopy (SEM), and the elemental composition was identified as Mn and O by energy-dispersive x-ray spectroscopy (EDS). The potential for BioMnOx to act as a catalyst in the degradation of paraquat was evaluated under three treatments: (1) a negative control (deionized water), (2) living alga with low BioMnOx plus hydrogen peroxide, and (3) living alga with high BioMnOx plus hydrogen peroxide. The results indicate that BioMnOx served as a catalyst in the Fenton-like reaction that could degrade more than 50% of the paraquat within 72 h. A kinetic study indicated that paraquat degradation by Fenton-like reactions using BioMnOx as a catalyst can be described by pseudo-first and pseudo-second order models. The pH level of the BioMnOx catalyst was neutral at the end of the experiment. In conclusion, BioMnOx is a viable and environmentally friendly catalyst to accelerate degradation of paraquat and other toxic chemicals.
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Li P, Zhuang Z, Du C, Xiang D, Zheng F, Zhang Z, Fang Z, Guo J, Zhu S, Chen W. Insights into the Mo-Doping Effect on the Electrocatalytic Performance of Hierarchical Co xMo yS Nanosheet Arrays for Hydrogen Generation and Urea Oxidation. ACS APPLIED MATERIALS & INTERFACES 2020; 12:40194-40203. [PMID: 32805843 DOI: 10.1021/acsami.0c06716] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Energy-efficient, low-cost, and highly durable catalysts for the electrochemical hydrogen evolution reaction (HER) and urea oxidation reaction (UOR) are extremely important for related sustainable energy systems. In the present work, hierarchical coassembled cobalt molybdenum sulfide nanosheets deposited on carbon cloth (CC) were synthesized as catalysts for hydrogen evolution and urea oxidation. By adjusting the doping amount of Mo, 2D nanosheets with different morphologies and compositions (CoxMoyS-CC) can be obtained. The as-prepared nanosheet materials with abundant active sites exhibit superior properties on the electrochemical HER and UOR in alkaline medium. Significantly, the Mo-doping concentration and composition of the formed nanosheets have large effects on the electrocatalytic activity. The fabricated nanosheets with optimal Mo doping (Co3Mo1S-CC) illustrate the best catalytic properties for the HER in N2-saturated 1.0 M KOH. A small overpotential (85 mV) is needed to meet the current density of 10 mA/cm2. This study indicates that the doping of an appropriate amount of molybdenum into CoS2 nanosheets can efficiently improve the catalytic performance. Also, the nanosheet catalyst exhibits an extremely high electrocatalytic activity for the UOR, and the electrochemical results indicate that a relatively low cell voltage of 1.50 V is needed to obtain the current density of 10 mA/cm2. The present work demonstrates the potential application of CoMoS nanosheets in the energy electrocatalysis area and the insights into performance-boosting through heteroatom doping and optimization of the composition and structure.
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Khamkeaw A, Asavamongkolkul T, Perngyai T, Jongsomjit B, Phisalaphong M. Interconnected Micro, Meso, and Macro Porous Activated Carbon from Bacterial Nanocellulose for Superior Adsorption Properties and Effective Catalytic Performance. Molecules 2020; 25:E4063. [PMID: 32899569 PMCID: PMC7570849 DOI: 10.3390/molecules25184063] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 09/02/2020] [Accepted: 09/03/2020] [Indexed: 11/16/2022] Open
Abstract
The porous carbon (bacterial cellulose (BC)-activated carbon (AC)(BA)) prepared via two-step activation of bacterial nanocellulose by treatments with potassium hydroxide (KOH) and then phosphoric acid (H3PO4) solutions showed superior adsorption properties and effective performance as catalyst support. BC-AC(BA) had an open and interconnected multi-porous structure, consisting of micropores (0.23 cm3/g), mesopores (0.26 cm3/g), and macropores (4.40 cm3/g). The BET surface area and porosity were 833 m2/g and 91.2%, respectively. The methylene blue adsorption test demonstrated that BC-AC(BA) was superior in its mass transfer rate and adsorption capacities. Moreover, BC-AC(BA) modified by H3PO4 treatment showed a significant enhancement of catalytic performance for dehydration of ethanol. At the reaction temperature of 250-400 °C, 30P/BC-AC(BA) gave ethanol conversion at 88.4-100%, with ethylene selectivity of 82.6-100%, whereas, high selectivity for diethyl ether (DEE) at 75.2%, at ethanol conversion of 60.1%, was obtained at the reaction temperature of 200 °C.
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Yuan M, Cui X, Zhu W, Tang H. Development of Environmentally Friendly Atom Transfer Radical Polymerization. Polymers (Basel) 2020; 12:E1987. [PMID: 32878287 PMCID: PMC7563397 DOI: 10.3390/polym12091987] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Revised: 08/22/2020] [Accepted: 08/24/2020] [Indexed: 02/06/2023] Open
Abstract
Atom transfer radical polymerization (ATRP) is one of the most successful techniques for the preparation of well-defined polymers with controllable molecular weights, narrow molecular weight distributions, specific macromolecular architectures, and precisely designed functionalities. ATRP usually involves transition-metal complex as catalyst. As the most commonly used copper complex catalyst is usually biologically toxic and environmentally unsafe, considerable interest has been focused on iron complex, enzyme, and metal-free catalysts owing to their low toxicity, inexpensive cost, commercial availability and environmental friendliness. This review aims to provide a comprehensive understanding of iron catalyst used in normal, reverse, AGET, ICAR, GAMA, and SARA ATRP, enzyme as well as metal-free catalyst mediated ATRP in the point of view of catalytic activity, initiation efficiency, and polymerization controllability. The principle of ATRP and the development of iron ligand are briefly discussed. The recent development of enzyme-mediated ATRP, the latest research progress on metal-free ATRP, and the application of metal-free ATRP in interdisciplinary areas are highlighted in sections. The prospects and challenges of these three ATRP techniques are also described in the review.
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The roles of long-range proton-coupled electron transfer in the directionality and efficiency of [FeFe]-hydrogenases. Proc Natl Acad Sci U S A 2020; 117:20520-20529. [PMID: 32796105 DOI: 10.1073/pnas.2007090117] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
As paradigms for proton-coupled electron transfer in enzymes and benchmarks for a fully renewable H2 technology, [FeFe]-hydrogenases behave as highly reversible electrocatalysts when immobilized on an electrode, operating in both catalytic directions with minimal overpotential requirement. Using the [FeFe]-hydrogenases from Clostridium pasteurianum (CpI) and Chlamydomonas reinhardtii (CrHydA1) we have conducted site-directed mutagenesis and protein film electrochemistry to determine how efficient catalysis depends on the long-range coupling of electron and proton transfer steps. Importantly, the electron and proton transfer pathways in [FeFe]-hydrogenases are well separated from each other in space. Variants with conservative substitutions (glutamate to aspartate) in either of two positions in the proton-transfer pathway retain significant activity and reveal the consequences of slowing down proton transfer for both catalytic directions over a wide range of pH and potential values. Proton reduction in the variants is impaired mainly by limiting the turnover rate, which drops sharply as the pH is raised, showing that proton capture from bulk solvent becomes critical. In contrast, hydrogen oxidation is affected in two ways: by limiting the turnover rate and by a large overpotential requirement that increases as the pH is raised, consistent with the accumulation of a reduced and protonated intermediate. A unique observation having fundamental significance is made under conditions where the variants still retain sufficient catalytic activity in both directions: An inflection appears as the catalytic current switches direction at the 2H+/H2 thermodynamic potential, clearly signaling a departure from electrocatalytic reversibility as electron and proton transfers begin to be decoupled.
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Yamaguchi Y, Aono R, Hayashi E, Kamata K, Hara M. Template-Free Synthesis of Mesoporous β-MnO 2 Nanoparticles: Structure, Formation Mechanism, and Catalytic Properties. ACS APPLIED MATERIALS & INTERFACES 2020; 12:36004-36013. [PMID: 32805787 DOI: 10.1021/acsami.0c08043] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Mesoporous β-MnO2 nanoparticles were synthesized by a template-free low-temperature crystallization of Mn4+ precursors (low-crystallinity layer-type Mn4+ oxide, c-distorted H+-birnessite) produced by the reaction of MnO4- and Mn2+. The Mn starting materials, pH of the reaction solution, and calcination temperatures significantly affect the crystal structure, surface area, porous structure, and morphology of the manganese oxides formed. The pH conditions during the precipitation of Mn4+ precursors are important for controlling the morphology and porous structure of β-MnO2. Nonrigid aggregates of platelike particles with slitlike pores (β-MnO2-1 and -2) were obtained from the combinations of NaMnO4/MnSO4 and NaMnO4/Mn(NO3)2, respectively. On the other hand, spherelike particles with ink-bottle shaped pores (β-MnO2-3) were formed in NaMnO4/Mn(OAc)2 with pH adjustment (pH 0.8). The specific surface areas for β-MnO2-1, -2, and -3 were much higher than those for nonporous β-MnO2 nanorods synthesized using a typical hydrothermal method (β-MnO2-HT). On the other hand, c-distorted H+-birnessite precursors with a high interlayer metal cation (Na+ and K+) content led to the formation of α-MnO2 with a 2 × 2 tunnel structure. These mesoporous β-MnO2 materials acted as effective heterogeneous catalysts for the aerobic oxidation of 5-hydroxymethylfurfural (HMF) to 2,5-furandicarboxylic acid (FDCA) as a bioplastic monomer and for the transformation of aromatic alcohols to the corresponding aldehydes, where the catalytic activities of β-MnO2-1, -2, and -3 were approximately 1 order of magnitude higher than that of β-MnO2-HT. β-MnO2-3 exhibited higher catalytic activity (especially for larger molecules) than the other β-MnO2 materials, and this is likely attributed to the nanometer-sized spaces.
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Wei B, Shang C, Wang X, Zhou G. Conductive FeOOH as Multifunctional Interlayer for Superior Lithium-Sulfur Batteries. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2020; 16:e2002789. [PMID: 32715639 DOI: 10.1002/smll.202002789] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2020] [Revised: 06/12/2020] [Indexed: 06/11/2023]
Abstract
The commercial course of Li-S batteries (LSBs) is impeded by several severe problems, such as low electrical conductivity of S, Li2 S2 , and Li2 S, considerable volume variation up to 80% during multiphase transformation and severe intermediation lithium polysulfides (LiPSs) shuttle effect. To solve above problems, conductive FeOOH interlayer is designed as an effective trapper and catalyst to accelerate the conversion of LiPSs in LSBs. FeOOH nanorod is effectively affinitive to S that Fe atoms act as Lewis acid sites to capture LiPSs via strong chemical anchoring capability and dispersion interaction. The excellent electrocatalytic effect enables that reduced charging potential barrier and enhanced electron/ion transport is realized on the FeOOH interlayer to promote LiPSs conversion. Significantly, Li2 S oxidation process is improved on the FeOOH interlayer determined as a combination of reduced Li2 S decomposition energy barrier and enhanced Li-ion transport. Therefore, the multifunctional FeOOH interlayer with conductive and catalytic features show strong chemisorption with LiPSs and accelerated LiPSs redox kinetics. As a result, LSBs with FeOOH interlayer displays high discharge capacity of 1449 mAh g-1 at 0.05 C and low capacity decay of 0.05% per cycle at 1 C, as well as excellent rate capability (449 mAh g-1 at 2 C).
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Czylkowska A, Rogalewicz B, Raducka A, Błaszczyk N, Maniecki T, Wieczorek K, Mierczyński P. Synthesis, Spectroscopic, Thermal and Catalytic Properties of Four New Metal (II) Complexes with Selected N- and O-Donor Ligands. MATERIALS (BASEL, SWITZERLAND) 2020; 13:ma13143217. [PMID: 32698342 PMCID: PMC7411774 DOI: 10.3390/ma13143217] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2020] [Revised: 06/27/2020] [Accepted: 07/17/2020] [Indexed: 06/11/2023]
Abstract
Four solid compounds with formulae: Co(OAc)2(Im)·H2O (I), Ni(OAc)2(Im)1.5·2H2O (II), Cu2(OAc)4(Im) (III) and Zn(OAc)2(Im)·H2O (IV) (where: Im = 1H-Imidazole) were prepared and characterized by chemical and elemental analysis, powder X-ray diffraction patterns and FTIR spectroscopy. Catalytic properties of each complex for styrene oxidation reaction were investigated. Furthermore, thermal properties of compounds were studied using the TG-DTG and DSC techniques under dry air atmosphere. Additionally, volatile thermal decomposition and fragmentation products were also investigated using the TG-FTIR spectra in air.
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Calizzi M, Mutschler R, Patelli N, Migliori A, Zhao K, Pasquini L, Züttel A. CO 2 Hydrogenation over Unsupported Fe-Co Nanoalloy Catalysts. NANOMATERIALS (BASEL, SWITZERLAND) 2020; 10:E1360. [PMID: 32664610 PMCID: PMC7408123 DOI: 10.3390/nano10071360] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/19/2020] [Revised: 07/06/2020] [Accepted: 07/09/2020] [Indexed: 12/13/2022]
Abstract
The thermo-catalytic synthesis of hydrocarbons from CO2 and H2 is of great interest for the conversion of CO2 into valuable chemicals and fuels. In this work, we aim to contribute to the fundamental understanding of the effect of alloying on the reaction yield and selectivity to a specific product. For this purpose, Fe-Co alloy nanoparticles (nanoalloys) with 30, 50 and 76 wt% Co content are synthesized via the Inert Gas Condensation method. The nanoalloys show a uniform composition and a size distribution between 10 and 25 nm, determined by means of X-ray diffraction and electron microscopy. The catalytic activity for CO2 hydrogenation is investigated in a plug flow reactor coupled with a mass spectrometer, carrying out the reaction as a function of temperature (393-823 K) at ambient pressure. The Fe-Co nanoalloys prove to be more active and more selective to CO than elemental Fe and Co nanoparticles prepared by the same method. Furthermore, the Fe-Co nanoalloys catalyze the formation of C2-C5 hydrocarbon products, while Co and Fe nanoparticles yield only CH4 and CO, respectively. We explain this synergistic effect by the simultaneous variation in CO2 binding energy and decomposition barrier as the Fe/Co ratio in the nanoalloy changes. With increasing Fe content, increased activation temperatures for the formation of CH4 (from 440 K to 560 K) and C2-C5 hydrocarbons (from 460 K to 560 K) are observed.
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Bonilla-Landa I, López-Hernández E, Barrera-Méndez F, Salas NC, Olivares-Romero JL. Hafnium(IV) Chloride Catalyzes Highly Efficient Acetalization of Carbonyl Compounds. Curr Org Synth 2020; 16:913-920. [PMID: 31984912 DOI: 10.2174/1570179416666190715100505] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2018] [Revised: 03/14/2019] [Accepted: 04/12/2019] [Indexed: 11/22/2022]
Abstract
BACKGROUND Hafnium(IV) tetrachloride efficiently catalyzes the protection of a variety of aldehydes and ketones, including benzophenone, acetophenone, and cyclohexanone, to the corresponding dimethyl acetals and 1,3-dioxolanes, under microwave heating. Substrates possessing acid-labile protecting groups (TBDPS and Boc) chemoselectively generated the corresponding acetal/ketal in excellent yields. AIMS AND OBJECTIVES In this study. the selective protection of aldehydes and ketones using a Hafnium(IV) chloride, which is a novel catalyst, under microwave heating was observed. Hence, it is imperative to find suitable conditions to promote the protection reaction in high yields and short reaction times. This study was undertaken not only to find a novel catalyst but also to perform the reaction with substrates bearing acid-labile protecting groups, and study the more challenging ketones as benzophenone. MATERIALS AND METHODS Using a microwave synthesis reactor Monowave 400 of Anton Paar, the protection reaction was performed on a raging temperature of 100°C ±1, a pressure of 2.9 bar, and an electric power of 50 W. More than 40 substrates have been screened and protected, not only the aldehydes were protected in high yields but also the more challenging ketones such as benzophenone were protected. All the products were purified by simple flash column chromatography, using silica gel and hexanes/ethyl acetate (90:10) as eluents. Finally, the protected substrates were characterized by NMR 1H, 13C and APCI-HRMS-QTOF. RESULTS Preliminary screening allowed us to find that 5 mol % of the catalyst is enough to furnish the protected aldehyde or ketone in up to 99% yield. Also it was found that substrates with a variety of substitutions on the aromatic ring (aldehyde or ketone), that include electron-withdrawing and electrondonating group, can be protected using this methodology in high yields. The more challenging cyclic ketones were also protected in up to 86% yield. It was found that trimethyl orthoformate is a very good additive to obtain the protected acetophenone. Finally, the protection of aldehydes with sensitive functional groups was performed. Indeed, it was found that substrates bearing acid labile groups such as Boc and TBDPS, chemoselectively generated the corresponding acetal/ketal compound while keeping the protective groups intact in up to 73% yield. CONCLUSION Hafnium(IV) chloride as a catalyst provides a simple, highly efficient, and general chemoselective methodology for the protection of a variety of structurally diverse aldehydes and ketones. The major advantages offered by this method are: high yields, low catalyst loading, air-stability, and non-toxicity.
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Revealing the structure of a catalytic combustion active-site ensemble combining uniform nanocrystal catalysts and theory insights. Proc Natl Acad Sci U S A 2020; 117:14721-14729. [PMID: 32554500 DOI: 10.1073/pnas.2002342117] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Supported metal catalysts are extensively used in industrial and environmental applications. To improve their performance, it is crucial to identify the most active sites. This identification is, however, made challenging by the presence of a large number of potential surface structures that complicate such an assignment. Often, the active site is formed by an ensemble of atoms, thus introducing further complications in its identification. Being able to produce uniform structures and identify the ones that are responsible for the catalyst performance is a crucial goal. In this work, we utilize a combination of uniform Pd/Pt nanocrystal catalysts and theory to reveal the catalytic active-site ensemble in highly active propene combustion materials. Using colloidal chemistry to exquisitely control nanoparticle size, we find that intrinsic rates for propene combustion in the presence of water increase monotonically with particle size on Pt-rich catalysts, suggesting that the reaction is structure dependent. We also reveal that water has a near-zero or mildly positive reaction rate order over Pd/Pt catalysts. Theory insights allow us to determine that the interaction of water with extended terraces present in large particles leads to the formation of step sites on metallic surfaces. These specific step-edge sites are responsible for the efficient combustion of propene at low temperature. This work reveals an elusive geometric ensemble, thus clearly identifying the active site in alkene combustion catalysts. These insights demonstrate how the combination of uniform catalysts and theory can provide a much deeper understanding of active-site geometry for many applications.
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Romano L, Stampanoni M. Microfabrication of X-ray Optics by Metal Assisted Chemical Etching: A Review. MICROMACHINES 2020; 11:E589. [PMID: 32545633 PMCID: PMC7344591 DOI: 10.3390/mi11060589] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 06/08/2020] [Accepted: 06/10/2020] [Indexed: 11/19/2022]
Abstract
High-aspect-ratio silicon micro- and nanostructures are technologically relevant in several applications, such as microelectronics, microelectromechanical systems, sensors, thermoelectric materials, battery anodes, solar cells, photonic devices, and X-ray optics. Microfabrication is usually achieved by dry-etch with reactive ions and KOH based wet-etch, metal assisted chemical etching (MacEtch) is emerging as a new etching technique that allows huge aspect ratio for feature size in the nanoscale. To date, a specialized review of MacEtch that considers both the fundamentals and X-ray optics applications is missing in the literature. This review aims to provide a comprehensive summary including: (i) fundamental mechanism; (ii) basics and roles to perform uniform etching in direction perpendicular to the <100> Si substrate; (iii) several examples of X-ray optics fabricated by MacEtch such as line gratings, circular gratings array, Fresnel zone plates, and other X-ray lenses; (iv) materials and methods for a full fabrication of absorbing gratings and the application in X-ray grating based interferometry; and (v) future perspectives of X-ray optics fabrication. The review provides researchers and engineers with an extensive and updated understanding of the principles and applications of MacEtch as a new technology for X-ray optics fabrication.
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Ali NA, Sazelee N, Yahya MS, Ismail M. Influence of K 2NbF 7 Catalyst on the Desorption Behavior of LiAlH 4. Front Chem 2020; 8:457. [PMID: 32656179 PMCID: PMC7326030 DOI: 10.3389/fchem.2020.00457] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2020] [Accepted: 05/01/2020] [Indexed: 11/13/2022] Open
Abstract
In this study, the modification of the desorption behavior of LiAlH4 by the addition of K2NbF7 was explored for the first time. The addition of K2NbF7 causes a notable improvement in the desorption behavior of LiAlH4. Upon the addition of 10 wt.% of K2NbF7, the desorption temperature of LiAlH4 was significantly lowered. The desorption temperature of the LiAlH4 + 10 wt.% K2NbF7 sample was lowered to 90°C (first-stage reaction) and 149°C (second-stage reaction). Enhancement of the desorption kinetics performance with the LiAlH4 + 10 wt.% K2NbF7 sample was substantiated, with the composite sample being able to desorb hydrogen 30 times faster than did pure LiAlH4. Furthermore, with the presence of 10 wt.% K2NbF7, the calculated activation energy values for the first two desorption stages were significantly reduced to 80 and 86 kJ/mol; 24 and 26 kJ/mol lower than the as-milled LiAlH4. After analysis of the X-ray diffraction result, it is believed that the in situ formation of NbF4, LiF, and K or K-containing phases that appeared during the heating process promoted the amelioration of the desorption behavior of LiAlH4 with the addition of K2NbF7.
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