Pub Date : 2023-01-01DOI: 10.1595/205651324x16963284171824
José R. Serrano, J. Javier López, Jaime Martín, Gabriela Bracho
Oxy-combustion is a promising concept to achieve an extremely clean combustion, independently of the fuel type, because, on the one hand, it is a NOx-free combustion and, on the other hand, the CO2 produced during combustion can be easily captured once the water vapor is removed from the exhaust gases stream, consequently allowing also carbon neutral operation. An existing 0D, mixing-controlled combustion model, developed for a standard diesel combustion scenario, has been adapted to the oxy-fuel combustion scenario. Initially, the model over-predicted the heat release at the end of the combustion process. The main model adaptation was to modify the relationship between the average YO2 and the effective YO2 (i.e. the one of the charge actually entrained by the spray), to be consistent with the significant increase in compression ratio needed in the oxy-fuel context. As a result, a model able to correctly predict the combustion behaviour at any operating condition has been obtained, which finally represents a very suitable tool to assist in the concept development.
{"title":"Extension of a Zero-Dimensional Mixing-Controlled Combustion Model for the Development of a NOx–Free System Based on the Oxy-Combustion Concept","authors":"José R. Serrano, J. Javier López, Jaime Martín, Gabriela Bracho","doi":"10.1595/205651324x16963284171824","DOIUrl":"https://doi.org/10.1595/205651324x16963284171824","url":null,"abstract":"Oxy-combustion is a promising concept to achieve an extremely clean combustion, independently of the fuel type, because, on the one hand, it is a NOx-free combustion and, on the other hand, the CO2 produced during combustion can be easily captured once the water vapor is removed from the exhaust gases stream, consequently allowing also carbon neutral operation. An existing 0D, mixing-controlled combustion model, developed for a standard diesel combustion scenario, has been adapted to the oxy-fuel combustion scenario. Initially, the model over-predicted the heat release at the end of the combustion process. The main model adaptation was to modify the relationship between the average YO2 and the effective YO2 (i.e. the one of the charge actually entrained by the spray), to be consistent with the significant increase in compression ratio needed in the oxy-fuel context. As a result, a model able to correctly predict the combustion behaviour at any operating condition has been obtained, which finally represents a very suitable tool to assist in the concept development.","PeriodicalId":14807,"journal":{"name":"Johnson Matthey Technology Review","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135913819","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1595/205651324x16963489202714
José Rodríguez-Fernández, Ángel Ramos, Víctor M. Domínguez, Blanca Giménez, Miriam Reyes, Juan J. Hernández
Recent progress has been made towards decarbonization of transport, which accounts for one quarter of the global carbon dioxide emissions. For the short-medium term, new EU and national energy and climate plans agree on a strategy based on the combination of increasing shares of electric vehicles with the promotion of sustainable fuels, especially if produced from residual feedstock and routes with low or zero net carbon emission. Hydrogen stands out among these fuels for its unique properties. This work analyses the potential of using hydrogen in a dual-fuel, compression-ignition engine running with three diesel-like fuels (conventional fossil diesel, advanced biodiesel and hydrotreated vegetable oil-HVO) and different hydrogen energy substitution ratios. The results were confronted with conventional diesel operation, revealing that dual-fuel combustion with hydrogen demands higher EGR rates and more advance combustion, leading to a remarked reduction of NOx emission at the expense of a penalty in energy consumption due mainly to unburnt hydrogen and wall heat losses. Unreacted hydrogen was ameliorated at high load. At low load, the use of biodiesel dual combustion permitted higher hydrogen substitution ratios and higher efficiencies than diesel and HVO.
{"title":"Hydrogen Use in a Dual-Fuel Compression-Ignition Engine with Alternative Biofuels","authors":"José Rodríguez-Fernández, Ángel Ramos, Víctor M. Domínguez, Blanca Giménez, Miriam Reyes, Juan J. Hernández","doi":"10.1595/205651324x16963489202714","DOIUrl":"https://doi.org/10.1595/205651324x16963489202714","url":null,"abstract":"Recent progress has been made towards decarbonization of transport, which accounts for one quarter of the global carbon dioxide emissions. For the short-medium term, new EU and national energy and climate plans agree on a strategy based on the combination of increasing shares of electric vehicles with the promotion of sustainable fuels, especially if produced from residual feedstock and routes with low or zero net carbon emission. Hydrogen stands out among these fuels for its unique properties. This work analyses the potential of using hydrogen in a dual-fuel, compression-ignition engine running with three diesel-like fuels (conventional fossil diesel, advanced biodiesel and hydrotreated vegetable oil-HVO) and different hydrogen energy substitution ratios. The results were confronted with conventional diesel operation, revealing that dual-fuel combustion with hydrogen demands higher EGR rates and more advance combustion, leading to a remarked reduction of NOx emission at the expense of a penalty in energy consumption due mainly to unburnt hydrogen and wall heat losses. Unreacted hydrogen was ameliorated at high load. At low load, the use of biodiesel dual combustion permitted higher hydrogen substitution ratios and higher efficiencies than diesel and HVO.","PeriodicalId":14807,"journal":{"name":"Johnson Matthey Technology Review","volume":"290 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135914177","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1595/205651324x16964141254874
Bowen Zhang, Rencheng Zhu, Yunjing Wang
The article places emphasis on the latest advancements in this field, particularly focusing on indoor and outdoor microplastic (MP) pollution, including their emission, behavior, and potential health hazards. Gaining an in-depth understanding of these factors is crucial for devising effective strategies to mitigate the impact of microplastics (MPs) on human health and the environment. Indoor MP abundance is generally higher than outdoor levels, with textiles serving as a primary source of indoor airborne MPs. Traffic-derived MP particles, MP fibers in residential areas, agricultural plastic mulch, marine MPs, and landfill sites appear to be contributors to outdoor atmospheric MP pollution. Factors such as wind direction, wind speed, precipitation, and snowfall, along with the physical characteristics and secondary suspension of MPs, collectively influence their behavior, distribution, and fate. Inhalation and ingestion constitute the main exposure pathways for airborne MPs, potentially leading to health issues like respiratory inflammation. Therefore, gaining a deeper insight into the behavior and impact mechanisms of atmospheric MPs aids in formulating effective risk management strategies to safeguard human health and maintain environmental sustainability.
{"title":"A Review of the Sources, Environmental Behaviors, and Human Health of Atmospheric Microplastics","authors":"Bowen Zhang, Rencheng Zhu, Yunjing Wang","doi":"10.1595/205651324x16964141254874","DOIUrl":"https://doi.org/10.1595/205651324x16964141254874","url":null,"abstract":"The article places emphasis on the latest advancements in this field, particularly focusing on indoor and outdoor microplastic (MP) pollution, including their emission, behavior, and potential health hazards. Gaining an in-depth understanding of these factors is crucial for devising effective strategies to mitigate the impact of microplastics (MPs) on human health and the environment. Indoor MP abundance is generally higher than outdoor levels, with textiles serving as a primary source of indoor airborne MPs. Traffic-derived MP particles, MP fibers in residential areas, agricultural plastic mulch, marine MPs, and landfill sites appear to be contributors to outdoor atmospheric MP pollution. Factors such as wind direction, wind speed, precipitation, and snowfall, along with the physical characteristics and secondary suspension of MPs, collectively influence their behavior, distribution, and fate. Inhalation and ingestion constitute the main exposure pathways for airborne MPs, potentially leading to health issues like respiratory inflammation. Therefore, gaining a deeper insight into the behavior and impact mechanisms of atmospheric MPs aids in formulating effective risk management strategies to safeguard human health and maintain environmental sustainability.","PeriodicalId":14807,"journal":{"name":"Johnson Matthey Technology Review","volume":"7 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135954183","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1595/205651323x16933888986996
Maila Danielis, Sara Colussi, Núria J. Divins, Lluís Soler, Alessandro Trovarelli, Jordi Llorca
In this review, we report on recent advances in the use of mechanochemistry to synthesize new catalytic materials. We report recent results obtained by our groups where a rational design of the milling parameters led to the synthesis of advanced materials with novel properties such as unconventional arrangements of metals on the surface of oxide support materials, highly dispersed metals or the stabilization of species in particular oxidation states. These properties resulted in superior catalytic performances of the mechanochemically-synthesized catalysts compared to their counterparts prepared by traditional impregnation methods. To illustrate these advances, we review the progress made in two important fields of catalysis where noble metals are used: (i) emission-control catalysis using Pd-based materials, and (ii) the development of photocatalysts to produce hydrogen based on Au and Pd materials.
{"title":"Mechanochemistry: A Green and Fast Method to Prepare A New Generation of Metal Supported Catalysts","authors":"Maila Danielis, Sara Colussi, Núria J. Divins, Lluís Soler, Alessandro Trovarelli, Jordi Llorca","doi":"10.1595/205651323x16933888986996","DOIUrl":"https://doi.org/10.1595/205651323x16933888986996","url":null,"abstract":"In this review, we report on recent advances in the use of mechanochemistry to synthesize new catalytic materials. We report recent results obtained by our groups where a rational design of the milling parameters led to the synthesis of advanced materials with novel properties such as unconventional arrangements of metals on the surface of oxide support materials, highly dispersed metals or the stabilization of species in particular oxidation states. These properties resulted in superior catalytic performances of the mechanochemically-synthesized catalysts compared to their counterparts prepared by traditional impregnation methods. To illustrate these advances, we review the progress made in two important fields of catalysis where noble metals are used: (i) emission-control catalysis using Pd-based materials, and (ii) the development of photocatalysts to produce hydrogen based on Au and Pd materials.","PeriodicalId":14807,"journal":{"name":"Johnson Matthey Technology Review","volume":"19 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135057166","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1595/205651323x16686891950941
Drasti Patel, H. Reid, Sarah Ball, D. Brett, P. Shearing
In Part I (1), the failure response of a 1 Ah layered pouch cell with a commercially available nickel manganese cobalt (NMC) cathode and graphite anode at 100% state of charge (SOC) (4.2 V) was investigated for two failure mechanisms: thermal and mechanical. The architectural changes to the whole-cell and deformations of the electrode layers are analysed after failure for both mechanisms. A methodology for post-mortem cell disassembly and sample preparation is proposed and demonstrated to effectively analyse the changes to the electrode surfaces, bulk microstructures and particle morphologies. Furthermore, insights into critical architectural weak points in LIB pouch cells, electrode behaviours and particle cracking are provided using invasive and non-invasive X-ray computed tomography techniques. The findings in this work demonstrate methods by which LIB failure can be investigated and assessed.
{"title":"X-Ray Computed Tomography for Failure Mechanism Characterisation within Layered Pouch Cells: Part II","authors":"Drasti Patel, H. Reid, Sarah Ball, D. Brett, P. Shearing","doi":"10.1595/205651323x16686891950941","DOIUrl":"https://doi.org/10.1595/205651323x16686891950941","url":null,"abstract":"In Part I (1), the failure response of a 1 Ah layered pouch cell with a commercially available nickel manganese cobalt (NMC) cathode and graphite anode at 100% state of charge (SOC) (4.2 V) was investigated for two failure mechanisms: thermal and mechanical. The architectural changes to the whole-cell and deformations of the electrode layers are analysed after failure for both mechanisms. A methodology for post-mortem cell disassembly and sample preparation is proposed and demonstrated to effectively analyse the changes to the electrode surfaces, bulk microstructures and particle morphologies. Furthermore, insights into critical architectural weak points in LIB pouch cells, electrode behaviours and particle cracking are provided using invasive and non-invasive X-ray computed tomography techniques. The findings in this work demonstrate methods by which LIB failure can be investigated and assessed.","PeriodicalId":14807,"journal":{"name":"Johnson Matthey Technology Review","volume":"1 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67351502","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1595/205651324x16965074891718
Seung Woo Lee, Hong-kil Baek, Kyeonghyeon Lee
CO2 regulations are becoming very stringent due to the goal of reducing greenhouse gases and achieving carbon neutrality. It has already become a common situation that electric vehicles are emerging as eco-friendly power systems rather than vehicles equipped with conventional internal combustion engines, and their share in the market is increasing. However, even with an internal combustion engine, CO2 can be drastically reduced if a carbon-free fuel such as hydrogen is used. Raw NOx emissions can be overcome to a certain level through ultra-lean burn operation, but in order to balance the amount of hydrogen and air in the limited space of combustion chamber, a drop in the engine's maximum output should be accepted. Hyundai Motor Company also previously developed an engine using hydrogen fuel, but was unable to progress to mass production. Since then, hybrid technology has become popular, and with the development of hydrogen injection devices, an era has arrived where the possibility of mass production can be increased. and for this reason, various studies on internal combustion engines using hydrogen fuel based on existing SI engines or CI engines are rapidly increasing recently. In this study, a hydrogen fuel engine was designed and manufactured based on the mass produced gasoline spark ignition engine. CO2 level was confirmed from initial performance evaluation, and it is found that raw NOx levels and maximum power were in a trade-off relationship with each other under same air-charging system application. In addition, the method to improve maximum engine torque was verified while maintaining the raw NOx level, and the maximum engine power improvement level was confirmed when raw NOx emissions were allowed to increase. Thereby it was shown that the potential of the carbon-neutral internal combustion engine.
{"title":"Potential of Hydrogen Internal Combustion Engine for the Decarbonized Passenger Vehicle","authors":"Seung Woo Lee, Hong-kil Baek, Kyeonghyeon Lee","doi":"10.1595/205651324x16965074891718","DOIUrl":"https://doi.org/10.1595/205651324x16965074891718","url":null,"abstract":"CO2 regulations are becoming very stringent due to the goal of reducing greenhouse gases and achieving carbon neutrality. It has already become a common situation that electric vehicles are emerging as eco-friendly power systems rather than vehicles equipped with conventional internal combustion engines, and their share in the market is increasing. However, even with an internal combustion engine, CO2 can be drastically reduced if a carbon-free fuel such as hydrogen is used. Raw NOx emissions can be overcome to a certain level through ultra-lean burn operation, but in order to balance the amount of hydrogen and air in the limited space of combustion chamber, a drop in the engine's maximum output should be accepted. Hyundai Motor Company also previously developed an engine using hydrogen fuel, but was unable to progress to mass production. Since then, hybrid technology has become popular, and with the development of hydrogen injection devices, an era has arrived where the possibility of mass production can be increased. and for this reason, various studies on internal combustion engines using hydrogen fuel based on existing SI engines or CI engines are rapidly increasing recently. In this study, a hydrogen fuel engine was designed and manufactured based on the mass produced gasoline spark ignition engine. CO2 level was confirmed from initial performance evaluation, and it is found that raw NOx levels and maximum power were in a trade-off relationship with each other under same air-charging system application. In addition, the method to improve maximum engine torque was verified while maintaining the raw NOx level, and the maximum engine power improvement level was confirmed when raw NOx emissions were allowed to increase. Thereby it was shown that the potential of the carbon-neutral internal combustion engine.","PeriodicalId":14807,"journal":{"name":"Johnson Matthey Technology Review","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135953834","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1595/205651323x16813753335431
Christopher Egan-Morriss, R. Kimber, N. A. Powell, J. Lloyd
The biosynthesis of Pd nanoparticles supported on microbial cells (bio-Pd) has attracted much recent interest, but the effect of solution chemistry on the process remains poorly understood. Biological buffers can be used to maintain physiological pH during the bioreduction of Pd(II) to Pd(0) by microbial cells, however, buffer components have the potential to complex Pd(II), and this may affect the subsequent microbe-metal interaction. In this study, a range of Pd(II) salts and biological buffers were selected to assess the impact of the solution chemistry on the rate of bioreduction of Pd(II) by Geobacter sulfurreducens, and the resulting biogenic Pd nanoparticles. The different buffer and Pd(II) combinations resulted in changes in the dominant Pd(II) species in solution, and this affected the amount of Pd recovered from solution by the microbial cells. The physical properties of the bio-Pd nanoparticles were altered under different solution chemistries; only slight variations were observed in the mean particle size (< 6 nm), but significant variations in particle agglomeration, the extent of Pd(II) bioreduction, and subsequent catalytic activity for the reduction of 4-nitrophenol were observed. The combination of sodium tetrachloropalladate and bicarbonate buffer resulted in bio-Pd with the smallest mean particle size, and the fastest initial rate of reaction for 4-NP reduction (0.33 min-1). Other solution chemistries appeared to damage the cells and result in bio-Pd with relatively poor catalytic performance. This work emphasises that future studies into bio-Pd synthesis should consider the importance of solution chemistry in controlling the speciation of Pd(II) and its impact on both the bioreduction process and the resulting properties of the nanoparticles produced, in order to maximize Pd(II) biorecovery and optimize catalytic properties.
{"title":"Impact of Solution Chemistry on the Biotechnological Synthesis and Properties of Palladium Nanoparticles","authors":"Christopher Egan-Morriss, R. Kimber, N. A. Powell, J. Lloyd","doi":"10.1595/205651323x16813753335431","DOIUrl":"https://doi.org/10.1595/205651323x16813753335431","url":null,"abstract":"The biosynthesis of Pd nanoparticles supported on microbial cells (bio-Pd) has attracted much recent interest, but the effect of solution chemistry on the process remains poorly understood. Biological buffers can be used to maintain physiological pH during the bioreduction of Pd(II) to Pd(0) by microbial cells, however, buffer components have the potential to complex Pd(II), and this may affect the subsequent microbe-metal interaction. In this study, a range of Pd(II) salts and biological buffers were selected to assess the impact of the solution chemistry on the rate of bioreduction of Pd(II) by Geobacter sulfurreducens, and the resulting biogenic Pd nanoparticles. The different buffer and Pd(II) combinations resulted in changes in the dominant Pd(II) species in solution, and this affected the amount of Pd recovered from solution by the microbial cells. The physical properties of the bio-Pd nanoparticles were altered under different solution chemistries; only slight variations were observed in the mean particle size (< 6 nm), but significant variations in particle agglomeration, the extent of Pd(II) bioreduction, and subsequent catalytic activity for the reduction of 4-nitrophenol were observed. The combination of sodium tetrachloropalladate and bicarbonate buffer resulted in bio-Pd with the smallest mean particle size, and the fastest initial rate of reaction for 4-NP reduction (0.33 min-1). Other solution chemistries appeared to damage the cells and result in bio-Pd with relatively poor catalytic performance. This work emphasises that future studies into bio-Pd synthesis should consider the importance of solution chemistry in controlling the speciation of Pd(II) and its impact on both the bioreduction process and the resulting properties of the nanoparticles produced, in order to maximize Pd(II) biorecovery and optimize catalytic properties.","PeriodicalId":14807,"journal":{"name":"Johnson Matthey Technology Review","volume":"1 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67352122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1595/205651323x16748145957998
D. Kadaifçiler, T. Unsal, E. Ilhan‐Sungur
Fungi commonly found in municipal water can participate in the natural biofilm formation on the surfaces of galvanized steel despite the toxic effect of Zn, and also depending on the age of the biofilm, fungal diversity may vary. To examine this hypothesis, natural biofilm formation was allowed on galvanized steel surfaces over 6 months in a model recirculating water system. Fungal colonies with different morphologies were obtained monthly from biofilm and water samples and then identified by both morphological and molecular approaches. In addition, the biofilm layer was examined by electrochemistry impedance spectroscopy (EIS) analyses and scanning electron microscopy. It was determined that the fungi were included in the natural aging biofilm formed on the galvanized steel surfaces over the experiment. The diversity and the number of fungi in the biofilm and water changed over the experiment. All of the fungi isolated from the biofilm and water were found to be members of the Ascomycota phylum. F. oxysporum was the first fungus to be involved in the biofilm formation process and also it is one of the main inhabitants of the biofilm together with Penicillium spp. In addition, EIS data showed that the structure of the biofilm changed as it ages. The results of this study may lead to a better understanding of natural aging biofilms involving fungi in municipal water systems, as well as the development of new strategies for effective disinfection of fungi based on biofilm age.
{"title":"Long-term Evaluation of Culturable Fungi in a Natural Aging Biofilm on Galvanized Steel Surface","authors":"D. Kadaifçiler, T. Unsal, E. Ilhan‐Sungur","doi":"10.1595/205651323x16748145957998","DOIUrl":"https://doi.org/10.1595/205651323x16748145957998","url":null,"abstract":"Fungi commonly found in municipal water can participate in the natural biofilm formation on the surfaces of galvanized steel despite the toxic effect of Zn, and also depending on the age of the biofilm, fungal diversity may vary. To examine this hypothesis, natural biofilm formation was allowed on galvanized steel surfaces over 6 months in a model recirculating water system. Fungal colonies with different morphologies were obtained monthly from biofilm and water samples and then identified by both morphological and molecular approaches. In addition, the biofilm layer was examined by electrochemistry impedance spectroscopy (EIS) analyses and scanning electron microscopy. It was determined that the fungi were included in the natural aging biofilm formed on the galvanized steel surfaces over the experiment. The diversity and the number of fungi in the biofilm and water changed over the experiment. All of the fungi isolated from the biofilm and water were found to be members of the Ascomycota phylum. F. oxysporum was the first fungus to be involved in the biofilm formation process and also it is one of the main inhabitants of the biofilm together with Penicillium spp. In addition, EIS data showed that the structure of the biofilm changed as it ages. The results of this study may lead to a better understanding of natural aging biofilms involving fungi in municipal water systems, as well as the development of new strategies for effective disinfection of fungi based on biofilm age.","PeriodicalId":14807,"journal":{"name":"Johnson Matthey Technology Review","volume":"18 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67352222","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-01-01DOI: 10.1595/205651323x16759335257118
M. Vlachou, H. R. Marchbank, E. Brooke, A. Kolpin
Gasoline vehicles have generally relied upon a combination of palladium and rhodium for more than 25 years to facilitate the required oxidative and reductive reactions of CO, HCs, and NOx. Recently, steady increases in the price of palladium relative to platinum have fuelled demand to reincorporate platinum into TWCs. However, the fundamental properties of platinum, including susceptibility toward sintering and inhibition under typical gasoline operating conditions, present significant challenges. This article presents an overview of the origins for these challenges, as well as select strategies for maximizing platinum’s contribution to modern-day TWCs. Optimisation of ceria-zirconia supports is one route by which platinum’s performance can be significantly improved through tuning of the ceria:zirconia ratio. Additionally, alloying platinum with a secondary PGM, e.g. rhodium, leverages complimentary properties of both metals, imparting stability and overall activity enhancements. Such routes not only enable PGM flexibility, but also provide opportunities to further improve TWC performance.
{"title":"Challenges and Opportunities for Platinum in the Modern Three-Way Catalyst","authors":"M. Vlachou, H. R. Marchbank, E. Brooke, A. Kolpin","doi":"10.1595/205651323x16759335257118","DOIUrl":"https://doi.org/10.1595/205651323x16759335257118","url":null,"abstract":"Gasoline vehicles have generally relied upon a combination of palladium and rhodium for more than 25 years to facilitate the required oxidative and reductive reactions of CO, HCs, and NOx. Recently, steady increases in the price of palladium relative to platinum have fuelled demand to reincorporate platinum into TWCs. However, the fundamental properties of platinum, including susceptibility toward sintering and inhibition under typical gasoline operating conditions, present significant challenges. This article presents an overview of the origins for these challenges, as well as select strategies for maximizing platinum’s contribution to modern-day TWCs. Optimisation of ceria-zirconia supports is one route by which platinum’s performance can be significantly improved through tuning of the ceria:zirconia ratio. Additionally, alloying platinum with a secondary PGM, e.g. rhodium, leverages complimentary properties of both metals, imparting stability and overall activity enhancements. Such routes not only enable PGM flexibility, but also provide opportunities to further improve TWC performance.","PeriodicalId":14807,"journal":{"name":"Johnson Matthey Technology Review","volume":"1 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67352232","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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