Flávio Pinheiro Valois, Kelly Christina Alves Bezerra, F. P. C. Assunção, Lucas Pinto Bernar, Simone Patrícia Aranha da Paz, Marcelo Costa Santos, Waldeci Paraguassu Feio, Renan Marcelo Pereira Silva, Neyson Mendonça, Douglas Alberto Rocha de Castro, Sergio Duvoisin Jr., Antônio Rafael Quadros Gomes, Victor Ricardo Costa Sousa, Marta Chagas Monteiro, N. Machado
Biomass-derived products are a promising way to substitute the necessity for petroleum-derived products, since lignocellulosic material is widely available in our atmosphere and contributes to the reduction of greenhouse gases (GHGs), due to zero net emissions of CO2. This study explores the impact of temperature and molarity on the pyrolysis of açaí seeds (Euterpe oleracea, Mart.) activated with KOH and subsequently on the yield of bio-oil, hydrocarbon content of bio-oil, antioxidant activity of bio-oil, and chemical composition of the aqueous phase. The experiments were carried out at 350, 400, and 450 °C and 1.0 atmosphere, with 2.0 M KOH, and at 450 °C and 1.0 atmosphere, with 0.5 M, 1.0 M, and 2.0 M KOH, at laboratory scale. The composition of bio-oils and the aqueous phase were determined by GC-MS, while the acid value, a physicochemical property of fundamental importance in biofuels, was determined by AOCS methods. The antioxidant activity of bio-oils was determined by the TEAC method. The solid phase (biochar) was characterized by X-ray diffraction (XRD). The diffractograms identified the presence of Kalicinite (KHCO3) in biochar, and those higher temperatures favor the formation peaks of Kalicinite (KHCO3). The pyrolysis of açaí seeds activated with KOH show bio-oil yields from 3.19 to 6.79 (wt.%), aqueous phase yields between 20.34 and 25.57 (wt.%), solid phase yields (coke) between 33.40 and 43.37 (wt.%), and gas yields from 31.85 to 34.45 (wt.%). The yield of bio-oil shows a smooth exponential increase with temperature. The acidity of bio-oil varied between 12.3 and 257.6 mg KOH/g, decreasing exponentially with temperature, while that of the aqueous phase varied between 17.9 and 118.9 mg KOH/g, showing an exponential decay behavior with temperature and demonstrating that higher temperatures favor not only the yield of bio-oil but also bio-oils with lower acidity. For the experiments with KOH activation, the GC-MS of bio-oil identified the presence of hydrocarbons (alkanes, alkenes, cycloalkanes, cycloalkenes, and aromatics) and oxygenates (carboxylic acids, phenols, ketones, and esters). The concentration of hydrocarbons varied between 10.19 and 25.71 (area.%), increasing with temperature, while that of oxygenates varied between 52.69 and 72.15 (area.%), decreasing with temperature. For the experiments with constant temperature, the concentrations of hydrocarbons in bio-oil increased exponentially with molarity, while those of oxygenates decreased exponentially, showing that higher molarities favor the formation of hydrocarbons in bio-oil. The antioxidant activity of bio-oils decreases with increasing temperature, as the content of phenolic compounds decreases, and it decreases with increasing KOH molarity, as higher molarities favor the formation of hydrocarbons. Finally, it can be concluded that chemical activation of açaí seeds with KOH favors not only the yield of bio-oil but also the content of hydrocarbons. The study of process
{"title":"Improving the Antioxidant Activity, Yield, and Hydrocarbon Content of Bio-Oil from the Pyrolysis of Açaí Seeds by Chemical Activation: Effect of Temperature and Molarity","authors":"Flávio Pinheiro Valois, Kelly Christina Alves Bezerra, F. P. C. Assunção, Lucas Pinto Bernar, Simone Patrícia Aranha da Paz, Marcelo Costa Santos, Waldeci Paraguassu Feio, Renan Marcelo Pereira Silva, Neyson Mendonça, Douglas Alberto Rocha de Castro, Sergio Duvoisin Jr., Antônio Rafael Quadros Gomes, Victor Ricardo Costa Sousa, Marta Chagas Monteiro, N. Machado","doi":"10.3390/catal14010044","DOIUrl":"https://doi.org/10.3390/catal14010044","url":null,"abstract":"Biomass-derived products are a promising way to substitute the necessity for petroleum-derived products, since lignocellulosic material is widely available in our atmosphere and contributes to the reduction of greenhouse gases (GHGs), due to zero net emissions of CO2. This study explores the impact of temperature and molarity on the pyrolysis of açaí seeds (Euterpe oleracea, Mart.) activated with KOH and subsequently on the yield of bio-oil, hydrocarbon content of bio-oil, antioxidant activity of bio-oil, and chemical composition of the aqueous phase. The experiments were carried out at 350, 400, and 450 °C and 1.0 atmosphere, with 2.0 M KOH, and at 450 °C and 1.0 atmosphere, with 0.5 M, 1.0 M, and 2.0 M KOH, at laboratory scale. The composition of bio-oils and the aqueous phase were determined by GC-MS, while the acid value, a physicochemical property of fundamental importance in biofuels, was determined by AOCS methods. The antioxidant activity of bio-oils was determined by the TEAC method. The solid phase (biochar) was characterized by X-ray diffraction (XRD). The diffractograms identified the presence of Kalicinite (KHCO3) in biochar, and those higher temperatures favor the formation peaks of Kalicinite (KHCO3). The pyrolysis of açaí seeds activated with KOH show bio-oil yields from 3.19 to 6.79 (wt.%), aqueous phase yields between 20.34 and 25.57 (wt.%), solid phase yields (coke) between 33.40 and 43.37 (wt.%), and gas yields from 31.85 to 34.45 (wt.%). The yield of bio-oil shows a smooth exponential increase with temperature. The acidity of bio-oil varied between 12.3 and 257.6 mg KOH/g, decreasing exponentially with temperature, while that of the aqueous phase varied between 17.9 and 118.9 mg KOH/g, showing an exponential decay behavior with temperature and demonstrating that higher temperatures favor not only the yield of bio-oil but also bio-oils with lower acidity. For the experiments with KOH activation, the GC-MS of bio-oil identified the presence of hydrocarbons (alkanes, alkenes, cycloalkanes, cycloalkenes, and aromatics) and oxygenates (carboxylic acids, phenols, ketones, and esters). The concentration of hydrocarbons varied between 10.19 and 25.71 (area.%), increasing with temperature, while that of oxygenates varied between 52.69 and 72.15 (area.%), decreasing with temperature. For the experiments with constant temperature, the concentrations of hydrocarbons in bio-oil increased exponentially with molarity, while those of oxygenates decreased exponentially, showing that higher molarities favor the formation of hydrocarbons in bio-oil. The antioxidant activity of bio-oils decreases with increasing temperature, as the content of phenolic compounds decreases, and it decreases with increasing KOH molarity, as higher molarities favor the formation of hydrocarbons. Finally, it can be concluded that chemical activation of açaí seeds with KOH favors not only the yield of bio-oil but also the content of hydrocarbons. The study of process ","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":"18 5","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139441538","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Chakarova, N. Drenchev, M. Mihaylov, K. Hadjiivanov
The interaction between O2 and reduced ceria nanocubes was mainly investigated using FTIR spectroscopy. Nanorods and nanoparticles were also studied for comparison. Adsorption of O2 at 100 K on unreduced ceria produces only O2 molecularly adsorbed on Ce4+ sites. The Ce3+ cations on ceria reduced by H2 at 773 K were monitored using the 2F5/2 → 2F7/2 electronic transition band at 2133–2095 cm−1. This band possesses a fine structure well resolved at 100 K. The positions of the individual components depend on the Ce3+ environment, including the presence of nearby species such as OH groups. Even at 100 K, adsorption of O2 on reduced ceria leads to fast oxidation of about half of the Ce3+ cations, including all Ce3+ sites bound to OH groups and carbonates, and the simultaneous formation of superoxo (O2−) and peroxo (O22−) species. The remaining Ce3+ sites disappear upon heating up to 348 K. At higher temperatures, the peroxo species decompose directly, yielding lattice oxygen. Superoxides are converted to hydroperoxides, which then decompose into terminal OH groups. Reduced samples evacuated at T < 773 K contain sorbed H2. Part of this hydrogen is also fast oxidized even at 100 K.
傅立叶变换红外光谱主要研究了氧气与还原铈纳米立方体之间的相互作用。此外，还对纳米棒和纳米颗粒进行了比较研究。在 100 K 时，未还原铈上吸附的 O2 只在 Ce4+ 位点上产生分子吸附的 O2。通过 2133-2095 cm-1 处的 2F5/2 → 2F7/2 电子转变带，对 773 K 下被 H2 还原的铈上的 Ce3+ 阳离子进行了监测。各个成分的位置取决于 Ce3+ 环境，包括附近物种（如 OH 基团）的存在。即使在 100 K 时，还原铈上吸附的 O2 也会导致大约一半的 Ce3+ 阳离子快速氧化，包括与 OH 基团和碳酸盐结合的所有 Ce3+ 位点，并同时形成超氧（O2-）和过氧（O22-）物种。在更高温度下，过氧化物直接分解，生成晶格氧。过氧化物转化为氢过氧化物，然后分解为末端羟基。在温度小于 773 K 时抽空的还原样品含有吸附的 H2。其中部分氢即使在 100 K 时也会被快速氧化。
{"title":"Interaction of O2 with Reduced Ceria Nanoparticles at 100–400 K: Fast Oxidation of Ce3+ Ions and Dissolved H2","authors":"K. Chakarova, N. Drenchev, M. Mihaylov, K. Hadjiivanov","doi":"10.3390/catal14010045","DOIUrl":"https://doi.org/10.3390/catal14010045","url":null,"abstract":"The interaction between O2 and reduced ceria nanocubes was mainly investigated using FTIR spectroscopy. Nanorods and nanoparticles were also studied for comparison. Adsorption of O2 at 100 K on unreduced ceria produces only O2 molecularly adsorbed on Ce4+ sites. The Ce3+ cations on ceria reduced by H2 at 773 K were monitored using the 2F5/2 → 2F7/2 electronic transition band at 2133–2095 cm−1. This band possesses a fine structure well resolved at 100 K. The positions of the individual components depend on the Ce3+ environment, including the presence of nearby species such as OH groups. Even at 100 K, adsorption of O2 on reduced ceria leads to fast oxidation of about half of the Ce3+ cations, including all Ce3+ sites bound to OH groups and carbonates, and the simultaneous formation of superoxo (O2−) and peroxo (O22−) species. The remaining Ce3+ sites disappear upon heating up to 348 K. At higher temperatures, the peroxo species decompose directly, yielding lattice oxygen. Superoxides are converted to hydroperoxides, which then decompose into terminal OH groups. Reduced samples evacuated at T < 773 K contain sorbed H2. Part of this hydrogen is also fast oxidized even at 100 K.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":"1 5","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-01-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139443653","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. N. Subramaniam, Jiaojiao Zheng, Zhentao Wu, Pei Sean Goh, Guangru Zhang
Researchers are actively pursuing the development of highly functional photocatalyst materials using environmentally friendly and sustainable resources. In this study, wheat straw biochar (BC), a by-product of biomass pyrolysis, was explored as a green, porous substrate and a carbon-based sensitizer to activate Fe-based photocatalysts under visible light. The research also delved into the impact of doping copper (Cu), chromium (Cr), and zinc (Zn) to enhance the photocatalytic activity of BC-Fe-based catalysts for the removal of methylene orange (MO) from water. Characterization results revealed a more than twofold increase in surface area and greater porosity, contributing to improved radical generation. BC demonstrated its dual functionality as a high surface area substrate and an electron sink, facilitating multistep electron movement and enhancing the photoactivity of the composite catalyst. Photodegradation experiments indicated that the combination of BC with Fe and Zn exhibited the highest performance, removing over 80% of MO within 120 min. Parametric studies highlighted the preference for an alkali pH, and the photocatalyst demonstrated efficient performance up to 30 ppm of dye. Radical scavenging experiments identified •OH and h+ as the most generated radicals. This study establishes that the green and sustainable BC holds promise as a material in the quest for more sustainable photocatalysts.
{"title":"Visible Light-Driven Organic Pollutant Removal Using Fe-Based Photocatalysts Supported by Wheat Straw Biochar","authors":"M. N. Subramaniam, Jiaojiao Zheng, Zhentao Wu, Pei Sean Goh, Guangru Zhang","doi":"10.3390/catal14010043","DOIUrl":"https://doi.org/10.3390/catal14010043","url":null,"abstract":"Researchers are actively pursuing the development of highly functional photocatalyst materials using environmentally friendly and sustainable resources. In this study, wheat straw biochar (BC), a by-product of biomass pyrolysis, was explored as a green, porous substrate and a carbon-based sensitizer to activate Fe-based photocatalysts under visible light. The research also delved into the impact of doping copper (Cu), chromium (Cr), and zinc (Zn) to enhance the photocatalytic activity of BC-Fe-based catalysts for the removal of methylene orange (MO) from water. Characterization results revealed a more than twofold increase in surface area and greater porosity, contributing to improved radical generation. BC demonstrated its dual functionality as a high surface area substrate and an electron sink, facilitating multistep electron movement and enhancing the photoactivity of the composite catalyst. Photodegradation experiments indicated that the combination of BC with Fe and Zn exhibited the highest performance, removing over 80% of MO within 120 min. Parametric studies highlighted the preference for an alkali pH, and the photocatalyst demonstrated efficient performance up to 30 ppm of dye. Radical scavenging experiments identified •OH and h+ as the most generated radicals. This study establishes that the green and sustainable BC holds promise as a material in the quest for more sustainable photocatalysts.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":"51 5","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-01-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139447955","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Ahmed T. Mosleh, Fatemah F. Al-Harbi, Soumaya M. Gouadria, S. Zyoud, H. Zahran, Mai S. A. Hussien, I. S. Yahia
Historically, the photocatalytic efficacy of graphitic carbon nitride (g-C3N4) has been constrained by a rapid charge recombination rate and restricted sensitivity to visible light. To overcome these limitations and enhance the performance of g-C3N4, the strategic formation of heterojunctions with semiconductor materials is deemed the optimal approach. The present study employed a facile sonication-assisted pyrolysis method to synthesize a g-C3N4@ZrO2 nanocomposite photocatalyst. This hybrid material was characterized extensively using a comprehensive suite of analytical techniques, including XRD, SEM, EDX, FTIR, and UV-Vis DRS. A comparative analysis of photocatalytic applications under identical conditions was conducted for all synthesized materials, wherein they were subjected to UVc light irradiation. The photocatalytic degradation of various dye models, such as MB, EY, and a combination of dyes, was assessed using the prepared nanocomposites. The g-C3N4@ZrO2 photocatalysts showcased superior photocatalytic performance, with a particular variant, g-CNZ6, exhibiting remarkable activity. With a bandgap energy of 2.57 eV, g-CNZ6 achieved impressive degradation efficiencies of 96.5% for MB and 95.6% for EY within 40 min. Following previous studies, the superoxide radical anions (O2−. and h+) were largely accountable for the degradation of MB. Therefore, the observed efficacy of the g-C3N4@ZrO2 nanocomposite photocatalyst can be attributed to the increased generation of these reactive species.
{"title":"Photodegradation of Wastewater Containing Organic Dyes Using Modified G-C3N4-Doped ZrO2 Nanostructures: Towards Safe Water for Human Beings","authors":"Ahmed T. Mosleh, Fatemah F. Al-Harbi, Soumaya M. Gouadria, S. Zyoud, H. Zahran, Mai S. A. Hussien, I. S. Yahia","doi":"10.3390/catal14010042","DOIUrl":"https://doi.org/10.3390/catal14010042","url":null,"abstract":"Historically, the photocatalytic efficacy of graphitic carbon nitride (g-C3N4) has been constrained by a rapid charge recombination rate and restricted sensitivity to visible light. To overcome these limitations and enhance the performance of g-C3N4, the strategic formation of heterojunctions with semiconductor materials is deemed the optimal approach. The present study employed a facile sonication-assisted pyrolysis method to synthesize a g-C3N4@ZrO2 nanocomposite photocatalyst. This hybrid material was characterized extensively using a comprehensive suite of analytical techniques, including XRD, SEM, EDX, FTIR, and UV-Vis DRS. A comparative analysis of photocatalytic applications under identical conditions was conducted for all synthesized materials, wherein they were subjected to UVc light irradiation. The photocatalytic degradation of various dye models, such as MB, EY, and a combination of dyes, was assessed using the prepared nanocomposites. The g-C3N4@ZrO2 photocatalysts showcased superior photocatalytic performance, with a particular variant, g-CNZ6, exhibiting remarkable activity. With a bandgap energy of 2.57 eV, g-CNZ6 achieved impressive degradation efficiencies of 96.5% for MB and 95.6% for EY within 40 min. Following previous studies, the superoxide radical anions (O2−. and h+) were largely accountable for the degradation of MB. Therefore, the observed efficacy of the g-C3N4@ZrO2 nanocomposite photocatalyst can be attributed to the increased generation of these reactive species.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":"24 17","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-01-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139448659","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A series of Zn salts were used as catalysts for the reaction of glycerol and urea to produce glycerol carbonate and it was found that ZnSO4 showed the highest catalytic activity. Furthermore, the effects of reaction parameters on the glycerol conversion and glycerol carbonate yield were studied in detail. The results indicated that the glycerol conversion and glycerol carbonate yield were increased with the reaction temperature, reaction time, and catalyst amount while the optimal reaction conditions were 140 °C, 240 min, catalyst amount of 5 wt% (based on the glycerol weight), and urea-to-glycerol molar ratio of 1.1:1. During the reaction, the ZnSO4 catalyst is transformed into Zn(NH3)2SO4 at the initial stage of the reaction and then further transformed into Zn(C3H6O3). Zn(C3H6O3) and (NH4)2SO4 may be the true active species for the activation of urea and glycerol, respectively. The reaction mechanism is proposed in this article. Based on the experimental results, a reaction kinetics model considering the change in volume of the reaction system was also established, and the model parameters were obtained by fitting the experimental data. The statistical results showed that the established kinetics model is accurate.
{"title":"Reaction Kinetics and Mechanism for the Synthesis of Glycerol Carbonate from Glycerol and Urea Using ZnSO4 as a Catalyst","authors":"Huajun Wang, Jingjing Ma","doi":"10.3390/catal14010041","DOIUrl":"https://doi.org/10.3390/catal14010041","url":null,"abstract":"A series of Zn salts were used as catalysts for the reaction of glycerol and urea to produce glycerol carbonate and it was found that ZnSO4 showed the highest catalytic activity. Furthermore, the effects of reaction parameters on the glycerol conversion and glycerol carbonate yield were studied in detail. The results indicated that the glycerol conversion and glycerol carbonate yield were increased with the reaction temperature, reaction time, and catalyst amount while the optimal reaction conditions were 140 °C, 240 min, catalyst amount of 5 wt% (based on the glycerol weight), and urea-to-glycerol molar ratio of 1.1:1. During the reaction, the ZnSO4 catalyst is transformed into Zn(NH3)2SO4 at the initial stage of the reaction and then further transformed into Zn(C3H6O3). Zn(C3H6O3) and (NH4)2SO4 may be the true active species for the activation of urea and glycerol, respectively. The reaction mechanism is proposed in this article. Based on the experimental results, a reaction kinetics model considering the change in volume of the reaction system was also established, and the model parameters were obtained by fitting the experimental data. The statistical results showed that the established kinetics model is accurate.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":"51 11","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139449455","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Muhammad Yousaf Arshad, Anam Suhail Ahmad, Jakub Mularski, Aleksandra Modzelewska, M. Jackowski, H. Pawlak-Kruczek, Lukasz Niedzwiecki
The advancement of plasma technology is intricately linked with the utilization of computational fluid dynamics (CFD) models, which play a pivotal role in the design and optimization of industrial-scale plasma reactors. This comprehensive compilation encapsulates the evolving landscape of plasma reactor design, encompassing fluid dynamics, chemical kinetics, heat transfer, and radiation energy. By employing diverse tools such as FLUENT, Python, MATLAB, and Abaqus, CFD techniques unravel the complexities of turbulence, multiphase flow, and species transport. The spectrum of plasma behavior equations, including ion and electron densities, electric fields, and recombination reactions, is presented in a holistic manner. The modeling of non-thermal plasma reactors, underpinned by precise mathematical formulations and computational strategies, is further empowered by the integration of machine learning algorithms for predictive modeling and optimization. From biomass gasification to intricate chemical reactions, this work underscores the versatile potential of plasma hybrid modeling in reshaping various industrial processes. Within the sphere of plasma catalysis, modeling and simulation methodologies have paved the way for transformative progress. Encompassing reactor configurations, kinetic pathways, hydrogen production, waste valorization, and beyond, this compilation offers a panoramic view of the multifaceted dimensions of plasma catalysis. Microkinetic modeling and catalyst design emerge as focal points for optimizing CO2 conversion, while the intricate interplay between plasma and catalysts illuminates insights into ammonia synthesis, methane reforming, and hydrocarbon conversion. Leveraging neural networks and advanced modeling techniques enables predictive prowess in the optimization of plasma-catalytic processes. The integration of plasma and catalysts for diverse applications, from waste valorization to syngas production and direct CO2/CH4 conversion, exemplifies the wide-reaching potential of plasma catalysis in sustainable practices. Ultimately, this anthology underscores the transformative influence of modeling and simulation in shaping the forefront of plasma-catalytic processes, fostering innovation and sustainable applications.
{"title":"Pioneering the Future: A Trailblazing Review of the Fusion of Computational Fluid Dynamics and Machine Learning Revolutionizing Plasma Catalysis and Non-Thermal Plasma Reactor Design","authors":"Muhammad Yousaf Arshad, Anam Suhail Ahmad, Jakub Mularski, Aleksandra Modzelewska, M. Jackowski, H. Pawlak-Kruczek, Lukasz Niedzwiecki","doi":"10.3390/catal14010040","DOIUrl":"https://doi.org/10.3390/catal14010040","url":null,"abstract":"The advancement of plasma technology is intricately linked with the utilization of computational fluid dynamics (CFD) models, which play a pivotal role in the design and optimization of industrial-scale plasma reactors. This comprehensive compilation encapsulates the evolving landscape of plasma reactor design, encompassing fluid dynamics, chemical kinetics, heat transfer, and radiation energy. By employing diverse tools such as FLUENT, Python, MATLAB, and Abaqus, CFD techniques unravel the complexities of turbulence, multiphase flow, and species transport. The spectrum of plasma behavior equations, including ion and electron densities, electric fields, and recombination reactions, is presented in a holistic manner. The modeling of non-thermal plasma reactors, underpinned by precise mathematical formulations and computational strategies, is further empowered by the integration of machine learning algorithms for predictive modeling and optimization. From biomass gasification to intricate chemical reactions, this work underscores the versatile potential of plasma hybrid modeling in reshaping various industrial processes. Within the sphere of plasma catalysis, modeling and simulation methodologies have paved the way for transformative progress. Encompassing reactor configurations, kinetic pathways, hydrogen production, waste valorization, and beyond, this compilation offers a panoramic view of the multifaceted dimensions of plasma catalysis. Microkinetic modeling and catalyst design emerge as focal points for optimizing CO2 conversion, while the intricate interplay between plasma and catalysts illuminates insights into ammonia synthesis, methane reforming, and hydrocarbon conversion. Leveraging neural networks and advanced modeling techniques enables predictive prowess in the optimization of plasma-catalytic processes. The integration of plasma and catalysts for diverse applications, from waste valorization to syngas production and direct CO2/CH4 conversion, exemplifies the wide-reaching potential of plasma catalysis in sustainable practices. Ultimately, this anthology underscores the transformative influence of modeling and simulation in shaping the forefront of plasma-catalytic processes, fostering innovation and sustainable applications.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":"49 6","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139449597","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The morphology of catalysts in microchannels plays a crucial role in the orbital maneuvering and networking applications of micro/nano satellites using hydrogen peroxide as a unit propellant. In this paper, a microfluidic reaction chip was designed and fabricated to detect the reaction rate of the catalytic decomposition of hydrogen peroxide solution by a microchannel catalytic bed. In addition, a silver thin film prepared by constant-current electroplating was used as a substrate for the microchannel catalyst. The results show that the ratio of surface area to area of silver film and the average particle size of silver particles have a significant positive correlation on the reaction rate of catalytic decomposition, while the thickness, silver content, and surface roughness of the silver film have no significant effect on the reaction rate of catalytic decomposition. The catalytic performance of the microchannel catalytic bed of silver thin film is greatly influenced by the conditions of electroplating, namely, the electroplating temperature (T), time (t), and current (I). And when I = 0.3 mA, t = 180 s, and T = 60 °C, the microchannel catalytic bed of the silver film prepared by electroplating reaches the optimal reaction rate for the catalytic decomposition of hydrogen peroxide solution. This study has the best process parameters for the design and optimization of heterogeneous catalysts applied to microfluidic reactors.
{"title":"Structure and Microchannel Catalytic Bed Performance of Silver Thin Films Prepared by Electroplating","authors":"Yong Yang, Y. Ye, Rui-qi Shen","doi":"10.3390/catal14010039","DOIUrl":"https://doi.org/10.3390/catal14010039","url":null,"abstract":"The morphology of catalysts in microchannels plays a crucial role in the orbital maneuvering and networking applications of micro/nano satellites using hydrogen peroxide as a unit propellant. In this paper, a microfluidic reaction chip was designed and fabricated to detect the reaction rate of the catalytic decomposition of hydrogen peroxide solution by a microchannel catalytic bed. In addition, a silver thin film prepared by constant-current electroplating was used as a substrate for the microchannel catalyst. The results show that the ratio of surface area to area of silver film and the average particle size of silver particles have a significant positive correlation on the reaction rate of catalytic decomposition, while the thickness, silver content, and surface roughness of the silver film have no significant effect on the reaction rate of catalytic decomposition. The catalytic performance of the microchannel catalytic bed of silver thin film is greatly influenced by the conditions of electroplating, namely, the electroplating temperature (T), time (t), and current (I). And when I = 0.3 mA, t = 180 s, and T = 60 °C, the microchannel catalytic bed of the silver film prepared by electroplating reaches the optimal reaction rate for the catalytic decomposition of hydrogen peroxide solution. This study has the best process parameters for the design and optimization of heterogeneous catalysts applied to microfluidic reactors.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":"36 14","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-01-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139382579","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Niloofar Mohammadpour, H. Kierzkowska‐Pawlak, J. Balcerzak, P. Uznański, J. Tyczkowski
Addressing the challenges associated with the highly exothermic nature of CO2 methanation, there is considerable interest in innovative catalyst designs on structural metallic supports. One promising solution in this regard involves thin films containing cobalt oxide within a carbon matrix, fabricated using the cold plasma deposition method (PECVD). The objective of this study was to search for a relationship between the molecular structure, nanostructure, and electronic structure of such films and their catalytic activity. The investigations employed various techniques, including X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), X-ray diffraction (XRD), UV-VIS absorption, and catalytic tests in the CO2 methanation process. Three types of films were tested: untreated as-deposited (ad-CoO), thermally post-treated (TT-CoO), and argon plasma post-treated (PT-CoO) films. Among these, TT-CoO exhibited the most favorable catalytic properties, demonstrating a CO2 conversion rate of 83%, CH4 selectivity of 98% at 400 °C, and stability during the catalytic process. This superior performance was attributed to the formation of nanoscale heterojunctions in the TT-CoO film, where p-type CoO nanocrystallites interacted with the n-type carbon matrix. This work provides compelling evidence highlighting the key role of nanoscale heterojunctions in shaping the properties of nanocatalysts in thermal catalysis. These findings suggest promising prospects for designing new catalytic systems by manipulating interactions at the nanoscale.
为了应对二氧化碳甲烷化的高放热性所带来的挑战，人们对金属结构支撑物上的创新催化剂设计产生了浓厚的兴趣。这方面一个很有前景的解决方案是使用冷等离子体沉积法（PECVD）在碳基质中制造含有氧化钴的薄膜。本研究的目的是寻找此类薄膜的分子结构、纳米结构和电子结构与其催化活性之间的关系。研究采用了多种技术，包括 X 射线光电子能谱 (XPS)、紫外光电子能谱 (UPS)、X 射线衍射 (XRD)、紫外可见吸收以及二氧化碳甲烷化过程中的催化测试。测试了三种类型的薄膜：未经处理的沉积薄膜（ad-CoO）、热后处理薄膜（TT-CoO）和氩等离子体后处理薄膜（PT-CoO）。其中，TT-CoO 表现出最有利的催化特性，二氧化碳转化率达到 83%，400 °C 时的甲烷选择性达到 98%，并且在催化过程中保持稳定。这种优异的性能归功于 TT-CoO 薄膜中形成的纳米级异质结，其中 p 型 CoO 纳米晶与 n 型碳基质相互作用。这项工作提供了令人信服的证据，凸显了纳米级异质结在热催化中塑造纳米催化剂特性的关键作用。这些发现为通过操纵纳米尺度的相互作用来设计新型催化系统提供了广阔的前景。
{"title":"Plasma-Deposited CoO–(Carbon Matrix) Thin-Film Nanocatalysts: The Impact of Nanoscale p-n Heterojunctions on Activity in CO2 Methanation","authors":"Niloofar Mohammadpour, H. Kierzkowska‐Pawlak, J. Balcerzak, P. Uznański, J. Tyczkowski","doi":"10.3390/catal14010038","DOIUrl":"https://doi.org/10.3390/catal14010038","url":null,"abstract":"Addressing the challenges associated with the highly exothermic nature of CO2 methanation, there is considerable interest in innovative catalyst designs on structural metallic supports. One promising solution in this regard involves thin films containing cobalt oxide within a carbon matrix, fabricated using the cold plasma deposition method (PECVD). The objective of this study was to search for a relationship between the molecular structure, nanostructure, and electronic structure of such films and their catalytic activity. The investigations employed various techniques, including X-ray photoelectron spectroscopy (XPS), ultraviolet photoelectron spectroscopy (UPS), X-ray diffraction (XRD), UV-VIS absorption, and catalytic tests in the CO2 methanation process. Three types of films were tested: untreated as-deposited (ad-CoO), thermally post-treated (TT-CoO), and argon plasma post-treated (PT-CoO) films. Among these, TT-CoO exhibited the most favorable catalytic properties, demonstrating a CO2 conversion rate of 83%, CH4 selectivity of 98% at 400 °C, and stability during the catalytic process. This superior performance was attributed to the formation of nanoscale heterojunctions in the TT-CoO film, where p-type CoO nanocrystallites interacted with the n-type carbon matrix. This work provides compelling evidence highlighting the key role of nanoscale heterojunctions in shaping the properties of nanocatalysts in thermal catalysis. These findings suggest promising prospects for designing new catalytic systems by manipulating interactions at the nanoscale.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":"52 2","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-01-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139386568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Min Zheng, Xiangzhou Li, Dulin Yin, Steven R. Kirk, Hui Li, Peng Zhou, Yanhong Yang
Carveol is a rare fine chemical with specific biological activities and functions in nature. The artificial synthesis of carveol from plentiful and cheap turpentine is expected to further improve development of pharmaceutical and industrial applications. A new green catalytic system for the preparation of high-value carveol from α-epoxypinane is presented. A novel ammonium salt solid acid (AC-COIMI-NH4PW) was obtained from phosphotungstic acid bonded with imidazole basic site on nitrogen-doped activated carbon which, after ammonia fumigation, presented an excellent catalytic performance for the selective rearrangement of α-epoxypinane to carveol in DMF as solvent under mild reaction conditions. At 90 °C for 2 h, the conversion of α-epoxypinane could reach 98.9% and the selectivity of carveol was 50.6%. The acidic catalytic sites exhibited superior durability and the catalytic performance can be restored by supplementing the lost catalyst. Based on the investigation of catalytic processes, a parallel catalytic mechanism for the main product was proposed from the rearrangement of α-epoxypinane on AC-COIMI-NH4PW.
{"title":"Ammonium Phosphotungstate Bonded on Imidazolized Activated Carbon for Selective Catalytic Rearrangement of α-Epoxypinane to Carveol","authors":"Min Zheng, Xiangzhou Li, Dulin Yin, Steven R. Kirk, Hui Li, Peng Zhou, Yanhong Yang","doi":"10.3390/catal14010036","DOIUrl":"https://doi.org/10.3390/catal14010036","url":null,"abstract":"Carveol is a rare fine chemical with specific biological activities and functions in nature. The artificial synthesis of carveol from plentiful and cheap turpentine is expected to further improve development of pharmaceutical and industrial applications. A new green catalytic system for the preparation of high-value carveol from α-epoxypinane is presented. A novel ammonium salt solid acid (AC-COIMI-NH4PW) was obtained from phosphotungstic acid bonded with imidazole basic site on nitrogen-doped activated carbon which, after ammonia fumigation, presented an excellent catalytic performance for the selective rearrangement of α-epoxypinane to carveol in DMF as solvent under mild reaction conditions. At 90 °C for 2 h, the conversion of α-epoxypinane could reach 98.9% and the selectivity of carveol was 50.6%. The acidic catalytic sites exhibited superior durability and the catalytic performance can be restored by supplementing the lost catalyst. Based on the investigation of catalytic processes, a parallel catalytic mechanism for the main product was proposed from the rearrangement of α-epoxypinane on AC-COIMI-NH4PW.","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":"30 2","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-01-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139451507","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Chenxuan Zhu, M. Guo, Ziqi Wang, Jiang He, Jiaqi Qiu, Yuxuan Guo, Yunfei Yan, Jingyu Ran, Zhongqing Yang
Carbon nitride MXene exhibits good metal conductivity, high photothermal conversion, carrier mobility, and high exposure of active sites, which makes it a promising co-catalyst for photothermal synergistic transformation of CO2. In this paper, Ti3CN/TiO2 heterojunction was constructed in situ using Ti3CN as TiO2 precursor to investigate the performance of Ti3CN MXene in photothermal synergistic transformation of CO2, and then the monolayer structure was utilized to enhance the interfacial charge transfer and improve the photothermal catalytic activity of Ti3CN. The catalysts were characterized by SEM, XRD, XPS, and UV-Vis DRS, and it was found the heterojunction constructed by monolayer MXene had a narrower bandgap and a higher carrier generation mobility, which, combined with the catalytic activity test, proved the single monolayer Ti3CN MXene had better photothermal synergistic conversion efficiency of CO2, and the heterojunction yield was 11.36 μmol·g−1·h−1 after layering, compared with that before layering (9.41%), which was 1.2 times higher than that before layering (9.41 μmol·g−1·h−1).
{"title":"Enhancement of Carrier Migration by Monolayer MXene Structure in Ti3CN/TiO2 Heterojunction to Achieve Efficient Photothermal Synergistic Transformation of CO2","authors":"Chenxuan Zhu, M. Guo, Ziqi Wang, Jiang He, Jiaqi Qiu, Yuxuan Guo, Yunfei Yan, Jingyu Ran, Zhongqing Yang","doi":"10.3390/catal14010035","DOIUrl":"https://doi.org/10.3390/catal14010035","url":null,"abstract":"Carbon nitride MXene exhibits good metal conductivity, high photothermal conversion, carrier mobility, and high exposure of active sites, which makes it a promising co-catalyst for photothermal synergistic transformation of CO2. In this paper, Ti3CN/TiO2 heterojunction was constructed in situ using Ti3CN as TiO2 precursor to investigate the performance of Ti3CN MXene in photothermal synergistic transformation of CO2, and then the monolayer structure was utilized to enhance the interfacial charge transfer and improve the photothermal catalytic activity of Ti3CN. The catalysts were characterized by SEM, XRD, XPS, and UV-Vis DRS, and it was found the heterojunction constructed by monolayer MXene had a narrower bandgap and a higher carrier generation mobility, which, combined with the catalytic activity test, proved the single monolayer Ti3CN MXene had better photothermal synergistic conversion efficiency of CO2, and the heterojunction yield was 11.36 μmol·g−1·h−1 after layering, compared with that before layering (9.41%), which was 1.2 times higher than that before layering (9.41 μmol·g−1·h−1).","PeriodicalId":9794,"journal":{"name":"Catalysts","volume":"32 8","pages":""},"PeriodicalIF":3.9,"publicationDate":"2024-01-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139389760","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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