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Stability and activity of nickel catalysts supported on diatomite for dry reforming of methane: Role of cerium and boron promoters

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Journal of the Energy Institute 2025年 120卷

作者： Azevedo, Amanda L. Melo, Dulce M.A. Silva, Yuri K.R.O. Oliveira, Ângelo A.S. Favacho, Vanessa S.S. Souza, Lalyson M.L.R. Rocha, Amanda R.C.C. braga, Renata M. Postgraduate Program in Chemistry Federal University of Rio Grande do Norte Natal Brazil Postgraduate Program in Materials Science and Engineering Federal University of Rio Grande do Norte Natal Brazil Postgraduate Program in Petroleum Science and Engineering Federal University of Rio Grande Do Norte Natal Brazil Agricultural School of Jundiaí Federal University of Rio Grande do Norte RN Macaíba Brazil

This study evaluates the activity and stability of nickel-based catalysts supported on diatomite and promoted with 1 or 2 wt% of cerium or boron for the dry reforming of methane (DRM). Diatomite, a naturally abundant and low-cost support, requires no complex synthesis procedures and remains relatively underexplored in DRM applications. Given the economic viability of using this material, the incorporation of promoters such as cerium and boron can enhance its catalytic properties, including resistance to coke formation, thermal stability, and activity at both low and high temperatures, thereby increasing its potential for industrial application. The support composition was analyzed by X-ray fluorescence (XRF), and its morphology was examined using scanning electron microscopy (SEM). The catalysts were characterized by SEM, X-ray diffraction (XRD), nitrogen physisorption, H2 temperature-programmed reduction (H2-TPR), thermogravimetric analysis (TGA), and Raman spectroscopy. The catalytic performance results indicated that cerium addition enhanced CO2 and CH4 conversion, with 2 wt% Ce-promoted catalyst stands out due to its significantly higher conversion rates and lower coke formation, as observed in TGA. The 2 wt% boron-promoted catalyst exhibited greater stability, with significant resistance to coke formation, despite showing lower CH4 conversion. SEM analysis revealed the presence of carbon filaments, particularly in the catalysts without boron, whereas boron-promoted catalysts showed reduced filamentous carbon formation. The activation energies derived from the Arrhenius plot further corroborate these findings, demonstrating that boron-promoted catalysts exhibited satisfactory performance at high temperatures (>800 °C), where the reaction is thermodynamically controlled. In turn, cerium-promoted catalysts achieved superior catalytic performance at ≤ 700 °C and performed similarly to boron-containing catalysts at higher temperatures. Therefore, both promoters impa

关键词： Thermogravimetric analysis

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Estimation of the main air pollutants from different biomasses under combustion atmospheres by artificial neural networks

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Chemosphere 2024年 352卷 141484页

作者： Monteiro, Thalyssa Oliveira Alves, Pedro Augusto Araújo da Silva de Almeida Nava barradas Filho, Alex Oliveira Villa-Vélez, Harvey Alexander Cruz, Glauber Postgraduate Program in Mechanical Engineering (PPGMEC) Department of Mechanics and Materials Federal Institute of Education Science and Technology of Maranhão (IFMA) Maranhão São Luís Brazil Postgraduate Program in Computer Science and Computational Mathematics (PPG-CCMC) Department of Computer Science University of São Paulo (USP) São Carlos São Paulo Brazil Data Analysis and Artificial Intelligence Laboratory (DARTi) Department of Computational Engineering Federal University of Maranhão (UFMA) Maranhão São Luís Brazil Department of Chemical Engineering Federal University of Maranhão (UFMA) Maranhão São Luís Brazil Processes and Thermal Systems Laboratory (LPSisTer) Department of Mechanical Engineering Federal University of Maranhão (UFMA) Maranhão São Luís Brazil

The production of biofuels to be used as bioenergy under combustion processes generates some gaseous emissions (CO, CO2, NOx, SOx, and other pollutants), affecting living organisms and requiring careful assessments. H... 详细信息

The production of biofuels to be used as bioenergy under combustion processes generates some gaseous emissions (CO, COb>2b>, NOb>xb>, SOb>xb>, and other pollutants), affecting living organisms and requiring careful assessments. However, obtaining such information experimentally for data evaluation is costly and time-consuming and its in situ obtaining for regional biomasses (e.g., those from Northeast brazil (NEb) is still a major challenge. This paper reports on the application of artificial neural networks (ANNs) for the prediction of the main air pollutants (CO, COb>2b>, NO, and SOb>2b>) produced during the direct biomass combustion (Nb>2b>/Ob>2b>:80/20%) with the use of ultimate analysis (carbon, hydrogen, nitrogen, sulfur, and oxygen). 116 worldwide biomasses were used as input data, which is a relevant alternative to overcome the lack of experimental resources in NEb and obtain such information. Cross-validation was conducted with k-fold to optimize the ANNs and performance was analyzed with the use of statistical errors for accuracy assessments. The results showed an acceptable statistical performance for all architectures of ANNs, with 0.001–12.41% MAPE, 0.001–5.82 mg Nm⁻³ MAE, and 0.03–52.30 mg Nm⁻³ RMSE, highlighting the high precision of the emissions studied. On average, the differences between predicted and real values for CO, COb>2b>, NO, and SOb>2b> emissions from NEb biomasses were approximately 0.01%, 10⁻⁶%, 0.14%, and 0.05%, respectively. Pearson coefficient provided consistent results of concentration of the ultimate analysis in relation to the emissions studied and effectiveness of the test set in the developed models. © 2024 Elsevier Ltd

关键词： brazilian northeastern Environmental statistics Evaluation metrics Gaseous emissions Predictive models Thermoconversion

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Pressure-driven homogenization of lithium disilicate glasses

arXiv

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arXiv 2023年

作者： bakhouch, Yasser buchner, Silvio Silveira, Rafael Abel Resende, Leonardo Pereira, Altair Soria Hasnaoui, Abdellatif Atila, Achraf LS2ME Faculté Polydisciplinaire Khouribga Sultan Moulay Slimane University of Beni Mellal B.P 145 Khouribga25000 Morocco Graduate Program in Materials Science Federal University of Rio Grande do Sul Porto Alegre Brazil Department of Material Science and Engineering Saarland University Saarbrücken66123 Germany

Lithium disilicate glasses and glass-ceramics are good potential candidates for biomedical applications and solid-state batteries, and serve as models of nucleation and crystal growth. Moreover, these glasses exhibit a phase separation that influences their nucleation and crystallization behavior. The atomistic mechanisms of the phase separation and their pressure dependence are unclear so far. Here, we used molecular dynamics simulations supported by experiments to assess the spatial heterogeneity of lithium disilicate glasses prepared under pressure. We show that the glass heterogeneity decreases with increasing the cooling pressure and almost disappears at pressures around 30 GPa. The origin of the heterogeneity is due to the attraction between Li cations to form clustering channels, which decreases with pressure. Through our results, we hope to provide valuable insights and guidance for making glass-ceramics with controlled crystallization. Copyright © 2023, The Authors. All rights reserved.

关键词： Phase separation

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Micromobility: Progress, benefits, challenges, policy and regulations, energy sources and storage, and its role in achieving sustainable development goals

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International Journal of Thermofluids 2023年 17卷

作者： Olabi, A.G. Wilberforce, Tabbi Obaideen, Khaled Sayed, Enas Taha Shehata, Nabila Alami, Abdul Hai Abdelkareem, Mohammad Ali Dept. of Sustainable and Renewable Energy Engineering University of Sharjah P.O. Box 27272 Sharjah United Arab Emirates Mechanical Engineering and Design Aston University School of Engineering and Applied Science Birmingham Aston TriangleB4 7ET United Kingdom Center for Advanced Materials Research University of Sharjah PO Box 27272 Sharjah United Arab Emirates Faculty of Engineering Minia University Elminia Egypt Environmental Science and Industrial Development Department Faculty of Postgraduate Studies for Advanced Sciences Beni-Suef University Beni-Suef Egypt

Micromobility is dominant in urban areas, enhancing the transportation sustainability and assisting in fulfilling the United Nations Sustainable Development Goals (SDGs). This work provides an overall assessment of micromobility: its role under SDGs, policy options, micromobility regulations, emerging technologies, utilisation determinants, energy source, and energy storage. The analysis shows that micromobility could play a major role in achieving the SDGs, specifically SDG 3 (Good Health and Well-being) by lowering toxic gas emissions and reducing projected traffic accidents. Also, the effect on SDG 8 (Decent Work and Economic Growth) by reducing the transportation footprint, on SDG 11 (Sustainable Cities and Communities) by increasing transposition accessibility, reducing traffic congestion and improving the air quality, and equally on SDG 12 (Responsible Consumption and Production) by reducing transportation footprint and increase the sources efficiency. Moreover, micromobility affects SDG 13 (Climate Action) by reducing the greenhouse gases. Furthermore, the analysis shows a clear gap in literature and publications on micromobility, especially in energy management and energy storage area. This review shows that new technology of renewable energy and energy storage could play a significant role in achieving the sustainability of micromobility therefore achieving the SDGs. © 2023

关键词： Sustainable development

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Computational Characterization of the Recently Synthesized Pristine and Porous 12-Atom-Wide Armchair Graphene Nanoribbon

arXiv

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arXiv 2025年

作者： da Gomes, Djardiel S. Felix, Isaac M. Radel, Willian F. Dias, Alexandre C. Ribeiro Junior, Luiz A. Pereira Junior, Marcelo L. State University of Campinas Gleb Wataghin Institute of Physics Department of Applied Physics Campinas São Paulo13083-859 Brazil University of Brasília Faculty UnB Planaltina Materials Science Postgraduate Program Federal District Brasília Brazil Center for Agri-food Science and Technology Federal University of Campina Grande Paraíba Pombal58840-000 Brazil University of Brasília Institute of Physics Physics Postgraduate Program Federal District Brasília70910900 Brazil Institute of Physics International Center of Physics University of Brasília Federal District Brasília70910-900 Brazil Institute of Physics University of Brasília Federal District Brasília70910-900 Brazil Computational Materials Laboratory University of Brasília Federal District Brasília70910900 Brazil University of Brasília College of Technology Department of Electrical Engineering Federal District Brasília70910-900 Brazil

Recently synthesized Porous 12-Atom-Wide Armchair Graphene Nanoribbons (12-AGNRs) [Nano Lett. 2024, 24, 10718-10723]exhibit tunable properties through periodic porosity, enabling precise control over their electronic, optical, thermal, and mechanical behavior. This work presents a comprehensive theoretical characterization of pristine and porous 12-AGNRs based on density functional theory (DFT) and molecular dynamics (MD) simulations. DFT calculations reveal substantial electronic modifications, including band gap widening and the emergence of localized states. Analyzed within the bethe–Salpeter equation (bSE) framework, optical properties highlight strong excitonic effects and significant absorption shifts. Thermal transport simulations indicate a pronounced reduction in conductivity due to enhanced phonon scattering at nanopores. At the same time, MD-based mechanical analysis shows decreased stiffness and strength while maintaining structural integrity. Despite these modifications, porous 12-AGNRs remain mechanically and thermally stable. These findings establish porosity engineering as a powerful strategy for tailoring graphene nanoribbons’ functional properties, reinforcing their potential for nanoelectronic, optoelectronic, and thermal management *** Codes 00-xx © 2025, CC bY.

关键词： Nanoribbons

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Comparison of Cu−Al−Ni−Mn−Zr shape memory alloy prepared by selective laser melting and conventional powder metallurgy

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Transactions of Nonferrous Metals Society of China 2020年第12期30卷 3322-3332页

作者： Dennis GERA Jonadabe SANTOS Cláudio SKIMINAMI Piter GARGARELLA Postgraduate Program in Materials Science and Engineering Federal University of São CarlosSão CarlosBrazil Materials Engineering Department Federal University of São CarlosR.Washington Luískm 235-SP 310São CarlosBrazil

This work aimed to investigate and critically analyze the differences in microstructural features and thermal stability of Cu−11.3Al−3.2Ni−3.0Mn−0.5Zr shape memory alloy processed by selective laser melting(SLM)and conventional powder *** specimens were produced by sintering 106−180μm pre-alloyed powders under an argon atmosphere at 1060°C without secondary *** specimens were consolidated through melting 32−106μm pre-alloyed powders on a Cu−10Sn *** properties were measured through Vickers hardness *** scanning calorimetry was conducted to assess the martensitic transformation temperatures.X-ray diffraction patterns were collected to identify the metallurgical *** and scanning electron microscopy was used to analyze the microstructural features.b′1 martensite was found,irrespective of the processing route,although coarser martensitic variants were present in *** conventional powder metallurgy samples,intergranular eutectoid constituents and stabilized austenite also formed at room ***-specimens showed similar average hardness values to the SLM-specimens,albeit with high standard deviation linked to the *** specimens processed by SLM showed reversible martensitic transformation(T0=171°C).PM-processed specimens did not show shape memory effects.

关键词： shape memory alloys powder metallurgy additive manufacturing selective laser melting Cu-based alloys

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Synthesis and characterization of ba and Sr celsian ceramics from zeolites obtained from amazonian bauxite waste clay

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Applied Clay science 2025年 275卷

作者： Nayara Aparecida Fonseca Couto bruno Apolo Miranda Figueira Igor Alexandre Rocha barreto Patricia Teresa Souza da Luz Oscar Jesus Choque Fernandez Marcondes Lima da Costa Postgraduate Program in Materials Engineering Federal Institute of Education Science and Technology of Pará 66093-020 Belém Brazil Institute of Geosciences Federal University of Pará 66075-110 Belém Brazil

This study explored the use of bauxite washing clay (bWC), a mining residue from the Amazon region, as a raw material for the synthesis of zeolites, followed by their conversion into barium and strontium celsian ceramics. The bWC, rich in gibbsite and kaolinite, demonstrated significant potential due to its high aluminum and silicon content. Zeolites were synthesized through alkaline activation with 1 M NaOH at 350 °C for 4 h, followed by hydrothermal treatment at 100 °C for 24 h. Ion exchange with ba 2+ and Sr 2+ cations was then performed, and the obtained materials were thermally treated at 1200 °C. The results showed the formation of monoclinic barium celsian with high crystallinity, while Sr-celsian exhibited partial conversion, retaining nepheline as a secondary phase. Monoclinic barium celsian exhibited superior mechanical properties, achieving a compressive strength of 15.9 MPa in compositions with lower silica content, whereas Sr-celsian reached 11.94 MPa. In conclusion, this study highlights the potential of bWC as a valuable and sustainable precursor for advanced ceramic production.

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boosting the Photocatalytic Activity of G-C3n4/Zno Heterojunctions Through Optimal Control of Mass Ratio

SSRN

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SSRN 2022年

作者： da Silva, Fausthon Fred da Silva, Rodolfo bezerra Silva, Thayse R. de Macedo, Daniel Araujo Su, bo Biomaterials Engineering Bristol Dental School University of Bristol Lower Maudlin Street BristolBS1 2LY United Kingdom PB João Pessoa58051-900 Brazil RN Mossoró59610-090 Brazil Materials Science and Engineering Postgraduate Program UFPB João Pessoa58051-900 Brazil

Carbon nitride (CN, g-C3N4) has emerged as a promising high-activity photocatalyst, despite some disadvantages like fast electron-hole recombination. The formation of CN-based heterojunctions is a viable strategy to overcome unwanted recombination processes. However, the precise control of the experimental parameters during the heterojunction formation is still needed to boost the photocatalytic efficiency. Herein, the influence of the mass ratio on the photocatalytic performance of CN/ZnO heterojunctions was investigated. The samples were obtained at room temperature via impregnation method and ultrasonic treatment. Heterojunctions were characterised by XRD and FT-IR, and interactions between the components were evidenced by the shifts in the diffraction patterns and vibrational spectra. The morphologies were investigated via SEM/TEM, confirming the formation of heterojunction interfaces. A strong influence of the CN/ZnO ratio was found on bandgaps, crystallite sizes. Photocatalytic activity was evaluated using rhodamine b dye in aqueous solution. High photocatalytic performances were obtained for CN/ZnO ≥ 1, and the best ratio was 2. The control of mass ratio changed the formation mechanism from type II heterojunction (CN/ZnO © 2022, The Authors. All rights reserved.

关键词： Carbon nitride

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Influence of submerged arc welding slag content variation on cementitious materials: A sustainable alternative

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Construction and building materials 2025年 483卷

作者： Castro-Lopes, S. Rodrigues, V.D. Marden, Sandro Peña-Garcia, R. Padrón-Hernández, E. berenguer, Romildo Federal Institute of Education Science and Technology of Pará PA Altamira Brazil Laboratory of Composite Materials and Structural Integrity Corrosion and Biocorrosion - CompoLab/LBC Federal University of Pernambuco PE Recife Brazil Federal University of Paraiba Department of Mechanical Engineering PB Joao Pessoa Brazil Federal Rural University of Pernambuco Postgraduate Program in Physics Engineering Academic Unit of Cabo de Santo Agostinho Cabo de Santo PE Agostinho Brazil Federal University of Pernambuco Department of Physics PE Recife Brazil Polytechnic School University of Pernambuco PE Recife Brazil Federal University of Pernambuco Department of Mechanical Engineering PE Recife Brazil

This study evaluates the effects of submerged arc welding (SAW) slag as a partial replacement for Portland cement in cementitious materials. Cement pastes with 5 %, 10 %, 15 %, 20 %, 25 %, and 30 % SAW slag were tested for compressive strength, tensile strength, carbonation resistance, phase formation, and environmental impact. The results revealed that up to 10 % SAW slag significantly enhanced compressive strength, with the 5 % replacement showing a 20.10 % increase in strength at 28 days compared to the control. The mechanical improvement was attributed to the formation of the CSH phase, which was confirmed by X-ray diffraction (XRD) and thermogravimetric analysis (TGA). Carbonation tests indicated that the 5 % SAW samples reduced carbonation by 5 % compared to the control, while the 10 % SAW samples showed a 1 % reduction. This suggests that SAW slag enhances the resistance of cementitious materials to CO2 attack, improving long-term durability. XRD analysis also identified an increase in amorphous phases in the SAW samples, particularly in the 5 % addition, further supporting the pozzolanic activity of SAW slag. Pozzolanic effectiveness coefficient analysis revealed synergistic effects for SAW slag blends, with optimal performance observed at 5 % replacement, in line with microstructural evidence of enhanced CSH gel formation. Environmental analysis demonstrated that replacing 10 % of Portland cement with SAW slag could reduce CO2 emissions by approximately 4564 kg annually, while a 15 % replacement could lead to a reduction of 6846 kg of CO2. These results underscore the potential of SAW slag as a sustainable and performance-enhancing alternative to conventional cement in concrete production. © 2025 Elsevier Ltd

关键词： Compressive strength

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A Review of Carbon dots (CDs) Application in Sensing and Removing Medical Waste 5

A Review of Carbon dots (CDs) Application in Sensing and Rem...

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5th International Conference on Energy, Environmental and Information System, ICENIS 2020

作者： Alkian, Ilham Sutanto, Heri Aprimanti Utami, bella Rafika Duri, Inten A'Yuni, Dewi Qurrota Hadiyanto, H Master Program of Environmental Science School of Postgraduate Studies Diponegoro University Semarang Indonesia Department of Physics Faculty of Science and Mathematics Diponegoro University Semarang Indonesia Department of Chemical Engineering Faculty of Engineering Diponegoro University Semarang Indonesia Smart Materials Research Center Diponegoro University Semarang Indonesia

Carbon dots materials (CDs) have the capability in the management of medical waste problem because of its advantage in the detection and degradation of pollutants. The synthesized CDs through various processes and raw materials have been applied to medical wastes, especially antibiotics such as tetracycline (TC), amoxicillin (AMX), para-Nitrophenol (p-NP), doxycycline (DC), ciprofloxacin (CIP), and oxytetracycline (OTC). These antibiotics are detected by utilizing changes in the luminescence property of CDs from the turn-off and turn-on mechanisms. Afterward, the degradation process is conducted using CDs as support materials agent semiconductors in the photosynthesis scheme. In general, CDs can be referred to as multifunction smart materials with the ability to detecting the presence of the antibiotics in simple, sensitive, and selective ways, and potency of medical pollutant removal clearly and effectively. © The Authors, published by EDP sciences, 2020.

关键词： Antibiotics

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