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Deactivation/Regeneration Studies in Structured Monolithic Ni-Based Catalysts Applied in Dry Reforming of Methane

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SSRN 2022年

作者： de Araújo, Ítalo R.S. Ribeiro, André T.S. Garcia, Ramón R.P. Sales, Deivson C.S. Almeida, Luciano C. Department of Chemical Engineering Technology and Geoscience Center Federal University of Pernambuco PE Recife50740-521 Brazil Polytechnic School of Pernambuco University of Pernambuco Rua Benfica 455 Madalena PE Recife50720-001 Brazil Materials Science and Engineering Graduate Program Federal University of Piauí PI Teresina Brazil Federal Rural University of Pernambuco Academic Unit of Cabo de Santo Agostinho PE Cabo de Santo Agostinho Brazil

In this work, the Ni/γ-Al2O3 (Ni/Al) and Ni/LA2O3-γ-Al2O3 (Ni/La-Al) catalysts were synthesized by the all-in-one method and used in the Dry Reforming of Methane (DRM). The catalysts were characterized and a smaller Ni crystallite size for the La-promoted catalyst was observed. The effects of the feed ratio (CH4:CO2), the use of La as a promoter of the catalyst support, and the use of the structured system in DRM reaction were investigated. Raman spectroscopy, scanning electron microscopy (SEM), and X-ray diffraction (XRD) were applied to investigate the catalytic deactivation effects. The deactivation of the structured catalysts was also evaluated by applying different weight hourly space velocities (WHSV): 20, 30, and 40 L gcat-1 h-1. Besides that, the regeneration of the catalysts was developed through the comparison of the treatment with CO2 and H2 atmospheres. The catalytic study of the powder samples showed that the lower the CH4:CO2 ratio the higher reactants conversion for both catalysts. It was also noted that the CH4:CO2 feed ratio of 4 provided a conversion 10 % higher for the Ni/La-Al catalyst in comparison with the Ni/Al catalyst. The analogy between the powder and structured systems implied greater conversion for the structured system. Furthermore, the greater and the lower deactivation of the structured systems were identified for the WHSV values of 40 and 20 L gcat-1 h-1, respectively. Finally, the regeneration treatment with CO2 showed to be more efficient than the treatment with H2 © 2022, The Authors. All rights reserved.

关键词： Carbon dioxide

Bioplastics from orange processing waste and poly(lactic acid)

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Future Foods

Future Foods 2025年 11卷

作者： Laís T. Possari Marina S. de Paula George F. Nunes Iago A. Reis Marcos V. Basaglia Caio G. Otoni Sílvia H.P. Bettini Federal University of São Carlos (UFSCar) Graduate Program in Materials Science and Engineering (PPGCEM) São Carlos SP 13565-905 Brazil Federal University of São Carlos (UFSCar) Department of Materials Engineering (DEMa) São Carlos SP 13565-905 Brazil University of Campinas (UNICAMP) Institute of Chemistry Campinas SP 13083-862 Brazil

Bioplastics have the potential to mitigate the aggravating crisis of plastic pollution. Valorizing agri-food side streams for such a purpose is particularly beneficial as it valorizes massively produced waste, thus contributing to the shift towards circular and regenerative productive chains. In this work, citrus pulp (CP) obtained as a by-product from orange juice production was upcycled into thermoplastic compounds via extrusion-assisted plasticization with glycerol. Compounds with poly(lactic acid) (PLA) were then produced by extrusion melt blending. An experimental 2² factorial design with a central point was performed to evaluate their mechanical, thermal, and biodegradation behavior. The levels for the variables plasticized CP (PCP) and glycerol contents were 30 and 70 % for PCP, and 40 and 60 % for glycerol. Calorimetry showed that PCP increased PLA free volume and chain mobility. Still, the different fractions of PCP and glycerol did not alter the melting behavior of the compounds significantly. PCP led to a progressive toughening effect on PLA. Mass loss after 90 d of soil burial reached 53–64 % for the formulations containing 70 % PCP, and PLA chain scission was accelerated at 30 % PCP with 60 % glycerol, and 70 % PCP with 40 % glycerol. This work opens new pathways to citrus biomass valorization by exploring CP, a scarcely investigated residue, and a novel processing strategy. The produced compounds can be applied as bio-based semi-rigid packaging and utensils.

关键词： Biodegradable plastic PLA Biomass Food waste Upcycling Citrus sinensis

Terahertz Landau Polaritons in Nano-slots: Ultrastrong Coupling under Extreme Spatial Confinement

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Terahertz Landau Polaritons in Nano-slots: Ultrastrong Coupl...

International Conference on Infrared and Millimeter Waves

作者： Dasom Kim Sunghwan Kim Dukhyung Lee Shuang Liang Fuyang Tay Michael J. Manfra Dai-Sik Kim Junichiro Kono Department of Electrical and Computer Engineering Rice University Houston TX USA Applied Physics Graduate Program Smalley-Curl Institute Rice University Houston TX USA Department of Physics Long-wavelength Nanotechnology Laboratory and Quantum Photonics Institute Ulsan National Institute of Science and Technology (UNIST) Ulsan South Korea Department of Physics and Astronomy Purdue University West Lafayette IN USA Birck Nanotechnology Center Purdue University West Lafayette IN USA Elmore Family School of Electrical and Computer Engineering Purdue University West Lafayette IN USA School of Materials Engineering Purdue University West Lafayette IN USA Department of Physics and Astronomy Rice University Houston TX USA Department of Material Science and NanoEngineering Rice University Houston TX USA

We report ultrastrong coupling of the cyclotron resonance of a two-dimensional electron gas in a GaAs quantum well to terahertz cavity photons under extreme confinement to the nanometer scale. This was realized by an array of nano-slots fabricated close to the quantum well layer on the GaAs substrate. Our terahertz magnetospectroscopic measurements revealed two polariton branches as a function of applied magnetic field. While the photon-like part of the two polariton branches was clearly observed, the matter-like part was generally elusive. Our electromagnetic simulations quantitatively reproduce our observation for the upper-polariton branch. However, for the lower-polariton branch, our simulations predict a pronounced resonance, which was absent in experimental spectra. This discrepancy may be a consequence of the breakdown of the dipole approximation in this extreme confinement situation.

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Effect of Tio2 Support for Co Nanoparticle Catalysts for Hydrogen Generation from Nabh4 Hydrolysis

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SSRN 2022年

作者： Altaf, Cigdem Tuc Colak, Tuluhan O. Minkina, Valentina G. Shabunya, Stanislav I. Sankir, Mehmet Demirci Sankir, Nurdan Kalinin, Vladimir I. Micro and Nanotechnology Graduate Program TOBB University of Economics and Technology Sogutozu Caddesi No 43 Sogutozu Ankara06560 Turkey A.V. Luikov Heat and Mass Transfer Institute The National Academy of Sciences of Belarus P. Brovka 15 Minsk220072 Belarus Department of Materials Science and Nanotechnology Engineering TOBB University of Economics and Technology Sogutozu Caddesi No 43 Sogutozu Ankara06560 Turkey

The influence of the structural differences in TiO2 (Degussa P25 and Mesh 325) as supporting materials for Co nanoparticles has been revealed in aqueous and alkaline NaBH4 hydrolysis. The activation energies for TiO2 (Mesh 325)/Co and Co/TiO2 (P25)/Co catalysts in aqueous solution of NaBH4 were 64.3 kJ . mol-1 and 56.76 kJ . mol-1, respectively. On the other hand, the activation energy values of the hydrolysis process in alkaline NaBH4 solutions using TiO2 (Mesh 325)/Co and TiO2 (P25)/Co catalysts have been calculated as 55 kJ . mol-1 and 45.2 kJ . mol-1, respectively. Consequently, hydrogen generation rate (HGR) for TiO2(Mesh 325)/Co and TiO2(P25)/Co in an aqueous-alkaline solution are 145 and 363 ml . min . gcat-1, respectively which are twice higher in that of aqueous NaBH4 hydrolysis reaction. © 2022, The Authors. All rights reserved.

关键词： Hydrolysis

Tailoring the Microstructure of a Cu-0.7cr-0.07zr Alloy Submitted to Ecap at Cryogenic Temperature for Improved Thermal Stability

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SSRN 2022年

作者： Oliveira, Pedro H.F. Magalhães, Danielle Cristina Camilo Unti, Luiz Fernando K. Cintho, O.M. Kliauga, Andrea M. Sordi, Vitor Luiz Federal University of São Carlos Graduate Program in Materials Science and Engineering Rod. Washington Luís km 235 São Carlos SP CEP 13565-905 Brazil Federal University of São Carlos Department of Materials Engineering Rod. Washington Luís km 235 São Carlos SP CEP 13565-905 Brazil Department of Mechanical Engineering Aeronautics Institute of Technology Praça Marechal Eduardo Gomes 50 SP São José dos CamposCEP 12228-900 Brazil Department of Materials Engineering State University of Ponta Grossa Av. General Carlos Cavalcanti PR Ponta GrossaCEP 84030-900 Brazil

Severe Plastic Deformation (SPD) routes, such as Equal Channel Angular Pressing (ECAP), are capable of producing ultrafine-grained (UFG) materials with outstanding mechanical properties. Although grain refinement and the increase in mechanical processing could be enhanced through ECAP processing at cryogenic temperatures, this route presents the drawback of microstructural instability, which is responsible for reversing the gain in mechanical properties and microstructural refinement when the material is stored at room temperature or submitted to relatively high temperatures. Aiming to design severely deformed and stable microstructures, this study investigated pure copper (Cu) and a commercial ITER-grade Cu-0.7Cr-0.07Zr alloy submitted to ECAP at 298 and 123 K followed by annealing heat treatments. ECAP processing introduced a high density of dislocations and vacancy concentration in the materials assessed. Pure Cu showed poor microstructural stability when long-term stored at room temperature after ECAP processing at cryogenic temperatures, and when submitted to annealing post-ECAP processing. In contrast, the Cu-0.7Cr-0.07Zr alloy submitted to cryo-ECAP showed outstanding thermal stability even when submitted to annealing at 673 K for 120 min. For this alloy, the fine Cr-rich precipitates were responsible for preventing static recovery and preserving a grain size of ~6.6 μm and an area fraction of recrystallized grains of 6.2%. Finally, it was possible to pave the way for the design of refined and stable microstructures after cryo-SPD processing. © 2022, The Authors. All rights reserved.

关键词： Equal channel angular pressing

Photoactivated theranostic nanomaterials based on aggregation-induced emission luminogens for cancer photoimmunotherapy

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Responsive Materials

Responsive materials 2024年第2期2卷

作者： Yuqi Tang Xing Wang Shilin Chen Quan Li Institute of Advanced Materials and School of Chemistry and Chemical Engineering Southeast University Nanjing China Department of Thoracic Surgery The Affiliated Cancer Hospital of Nanjing Medical University Jiangsu Cancer Hospital and Jiangsu Institute of Cancer Research Nanjing China Materials Science Graduate Program Kent State University Kent Ohio USA

In this study, a series of high liposoluble near-infrared emissive aggregation-induced emission luminogens with triphenylamine derivatives as donor units and 1-indanone as electron acceptor units are developed. Specifically, MTTOI has promising lipid droplets targeting ability and viscosity-response characteristics, and it can monitor the viscosity fluctuations in living cells in real time. It is found that MTTOI is able to fulfill the activation of the apoptosis-related signaling pathways under white light, and it can also activate the ferroptosis to synergize apoptosis resulting in tumor elimination. Interestingly, the occurrence of ferroptosis is positively related to the enhancement of immunogenic cell-death effect, thus boosting the tumor infiltration of CD8 + T cells and reducing the proportion of regulatory T cells by cooperating with dendritic cells, which can not only carry out primary antitumor treatment, but also prevent tumor metastasis through strong immunological memory effect. Moreover, in vivo experimental results confirm that MTTOI successfully effectuates fatty liver tissue imaging. MTTOI fluorescence signals can be captured at the tumor site after 3 days of administration due to its high fat-solubility and ease of fusion with tumors. This classic example could promote the further development of phototherapeutic agents in preclinical research and clinical applications.

关键词： cancer photoimmunotherapy ferroptosis near-infrared aggregation-induced emission luminogen photoactivated theranostic nanomaterial viscosity response

Influence of Crystallization on Corrosion and Mechanical Properties of Two Novel Fecrmonbb and Fecrmonib Amorphous Alloys

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SSRN 2022年

作者： Batalha, Weverson Capute Roche, Virginie Champion, Yannick Mantel, Marc Verdier, Marc Martin, Vincent Kiminami, Claudio Shyint Jorge Junior, Alberto Moreira Moreira Univ. Grenoble Alpes Univ. Savoie Mont Blanc CNRS Grenoble INP LEPMI Grenoble38000 France Institute of Engineering and Management Univ. Grenoble Alpes France Univ. Grenoble Alpes Univ. Savoie Mont Blanc CNRS Grenoble INP SIMAP Grenoble38000 France Graduate Program of Materials Science and Engineering Federal University of São Carlos DEMa São Carlos13565-905 Brazil

The influence of thermally induced devitrification on microstructure, corrosion, and mechanical properties of two novel Fe-based amorphous alloys has been investigated in this work (FeCrMoXB, where X=Nb, Ni). Hence, providing an overview of the perspectives for using these new alloys as coatings. Ribbons were produced by melt spinning. Samples were characterized using X-ray diffraction (XRD), differential scanning calorimetry (DSC), and transmission electron microscopy (TEM), accompanied by chemical analysis via energy dispersive spectroscopy (EDS). As-cast ribbons were amorphous. Considering DSC data of such ribbons, they were heat-treated under an Ar protective atmosphere to simulate crystallization that may occur during coating processing. The mechanical behavior was evaluated by nanoindentation. High hardness (around 14 GPa) and elastic modulus (>220 GPa) were identified for both compositions. Corrosion properties were analyzed by potentiodynamic polarization in seawater at three different pHs. Both compositions in the amorphous state exhibited outstanding corrosion resistance, forming a broad passivation plateau in the various media analyzed. After devitrification, the Nb-containing alloy preserved excellent corrosion behavior, with a slight decrease in corrosivity up to 720°C, better than the Ni-containing alloy that exhibited lower corrosion resistance with good corrosivity kept only up to 690°C. Results indicate outstanding corrosion behavior and wear resistance, indicating that these materials are promising for coating application through different techniques. © 2022, The Authors. All rights reserved.

关键词： Corrosion resistance

Local and global measures of the shear moduli of jammed disk packings

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arXiv

arXiv 2023年

作者： Zhang, Shiyun Jin, Weiwei Wang, Dong Xu, Ding Zhang, Jerry Shattuck, Mark D. O’Hern, Corey S. Department of Physics University of Science and Technology of China Anhui Hefei230026 China Department of Mechanical Engineering and Materials Science Yale University New HavenCT06520 United States Benjamin Levich Institute and Physics Department The City College of New York New YorkNY10031 United States Department of Physics Yale University New HavenCT06520 United States Department of Applied Physics Yale University New HavenCT06520 United States Graduate Program in Computational Biology and Bioinformatics Yale University New HavenCT06520 United States

Strain-controlled isotropic compression gives rise to jammed packings of repulsive, frictionless disks with either positive or negative global shear moduli. We carry out computational studies to understand the contributions of the negative shear moduli to the mechanical response of jammed disk packings. We first decompose the ensemble-averaged, global shear modulus as hGi = (1 − F−)hG+i + F−hG−i, where F− is the fraction of jammed packings with negative shear moduli and hG+i and hG−i are the average values from packings with positive and negative moduli, respectively. We show that hG+i and h|G−|i obey different power-law scaling relations above and below pN2 ∼ 1. For pN2 > 1, both hG+iN and h|G−|iN ∼ (pN2)β, where β ∼ 0.5 for repulsive linear spring interactions. Despite this, hGiN ∼ (pN2)β0 with β0 & 0.5 due to the contributions from packings with negative shear moduli. We show further that the probability distribution of global shear moduli P(G) collapses at fixed pN2 and different values of p and N. We calculate analytically that P(G) is a Gamma distribution in the pN2 1 limit. As pN2 increases, the skewness of P(G) decreases and P(G) becomes a skew-normal distribution with negative skewness in the pN2 1 limit. We also partition jammed disk packings into subsystems using Delanunay triangulation of the disk centers to calculate local shear moduli. We show that the local shear moduli defined from groups of adjacent triangles can be negative even when G > 0. The spatial correlation function of local shear moduli C(~r) displays weak correlations for pn2sub −2, where nsub is the number of particles within each subsystem. However, C(~r) begins to develop long-ranged spatial correlations with four-fold angular symmetry for pn2sub & 10−2 © 2023, CC BY-NC-ND.

关键词： Elastic moduli

Magnetically Tuned Continuous Transition from Weak to Strong Coupling in Terahertz Magnon Polaritons

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arXiv

arXiv 2022年

作者： Baydin, Andrey Hayashida, Kenji Makihara, Takuma Tay, Fuyang Ma, Xiaoxuan Ren, Wei Ma, Guohong Noe, G. Timothy Katayama, Ikufumi Takeda, Jun Nojiri, Hiroyuki Cao, Shixun Bamba, Motoaki Kono, Junichiro Department of Electrical and Computer Engineering Rice University HoustonTX77005 United States The Smalley-Curl Institute Rice University HoustonTX77005 United States Division of Applied Physics Graduate School of Engineering Hokkaido University Hokkaido Sapporo060-8628 Japan Department of Physics and Astronomy Rice University HoustonTX77005 United States Applied Physics Graduate Program Smalley-Curl Institute Rice University HoustonTX77005 United States Department of Physics International Center of Quantum and Molecular Structures Materials Genome Institute Shanghai University Shanghai200444 China Department of Physics Graduate School of Engineering Science Yokohama National University Yokohama240-8501 Japan Institute for Materials Research Tohoku University Sendai980-8577 Japan The Hakubi Center for Advanced Research Kyoto University Kyoto606-8502 Japan Department of Physics I Kyoto University Kyoto606-8502 Japan PRESTO Japan Science and Technology Agency Kawaguchi332-0012 Japan Department of Materials Science and NanoEngineering Rice University HoustonTX77005 United States

Depending on the relative rates of coupling and dissipation, a light-matter coupled system is either in the weak- or strong-coupling regime. Here, we present a unique system where the coupling rate continuously increases with an externally applied magnetic field while the dissipation rate remains constant, allowing us to monitor a weak-to-strong coupling transition as a function of magnetic field. We observed a Rabi splitting of a terahertz magnon mode in yttrium orthoferrite above a threshold magnetic field of ∼14 T. Based on a microscopic theoretical model, we show that with increasing magnetic field the magnons transition into magnon polaritons through an exceptional point, which will open up new opportunities for in situ control of non-Hermitian systems. Copyright © 2022, The Authors. All rights reserved.

关键词： Polariton