Pub Date : 2022-01-01DOI: 10.1595/205651322x16482034395036
Nahdhoit Ahamada Rachid, Nihal Doğruöz Güngör
Health issue and pollution of the environment are mainly caused by using chemicals and synthetic materials. This issue incites scientists to research for new biological compounds beneficial to human being. Caves, being extreme environments might be potential sources of these compounds. Actinobacteria, one of the main groups that are colonizing these environments, are known to contribute most of natural bioactive compounds. To investigate the potential uses of Parsik Cave Actinobacteria, identification of this group of isolates and the investigation of their secreted biological compounds constituted the principal aim of our study. The identification was achieved by sequencing 16S rRNA genes of 41 selected bacteria in which 28 species were identified as Actinobacteria. Microbacterium (21%), Pseudoarthrobacter (14%) were the most identified Actinobacteria genera. Antimicrobial effects of the isolates P1 and P16 were observed against standard microorganisms like Candida albicans. The GC-MS analysis of their broth shown antimicrobials, antioxidants, anticancer, and unknown compounds. PKS and NRPS were amplified respectively in 32.1 % and 53.5% of the identified Actinobacteria while their 25% have been both NRPS and PKS amplified. Amylase, gelatinase, cellulase, DNase, urease, and casein hydrolysing activities were observed in the identified Actinobacteria. Our results show that Actinobacteria from Parsık Cave might be good sources of industrial and biotechnological compounds. Furthermore, discover of new bioactive compounds from these bacteria is promising due to many unknown compounds observed in the GC-MS analysis and the high % of NRPS/PKS genes amplification.
{"title":"Screening of bioactive compounds for biomedical and industrial uses from Actinobacteria isolated from the Parsik Cave (Turkey)","authors":"Nahdhoit Ahamada Rachid, Nihal Doğruöz Güngör","doi":"10.1595/205651322x16482034395036","DOIUrl":"https://doi.org/10.1595/205651322x16482034395036","url":null,"abstract":"Health issue and pollution of the environment are mainly caused by using chemicals and synthetic materials. This issue incites scientists to research for new biological compounds beneficial to human being. Caves, being extreme environments might be potential sources of these compounds. Actinobacteria, one of the main groups that are colonizing these environments, are known to contribute most of natural bioactive compounds. To investigate the potential uses of Parsik Cave Actinobacteria, identification of this group of isolates and the investigation of their secreted biological compounds constituted the principal aim of our study. The identification was achieved by sequencing 16S rRNA genes of 41 selected bacteria in which 28 species were identified as Actinobacteria. Microbacterium (21%), Pseudoarthrobacter (14%) were the most identified Actinobacteria genera. Antimicrobial effects of the isolates P1 and P16 were observed against standard microorganisms like Candida albicans. The GC-MS analysis of their broth shown antimicrobials, antioxidants, anticancer, and unknown compounds. PKS and NRPS were amplified respectively in 32.1 % and 53.5% of the identified Actinobacteria while their 25% have been both NRPS and PKS amplified. Amylase, gelatinase, cellulase, DNase, urease, and casein hydrolysing activities were observed in the identified Actinobacteria. Our results show that Actinobacteria from Parsık Cave might be good sources of industrial and biotechnological compounds. Furthermore, discover of new bioactive compounds from these bacteria is promising due to many unknown compounds observed in the GC-MS analysis and the high % of NRPS/PKS genes amplification.","PeriodicalId":14807,"journal":{"name":"Johnson Matthey Technology Review","volume":"1 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67351284","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 : 2022-01-01DOI: 10.1595/205651323x16698159435916
B. Lipshutz
Ask any card-carrying organic chemist which metal reigns supreme today in synthetic organic chemistry and most, if not all, will quickly identify palladium as the clear winner. But this soft, silver-white metal is only one of six that make up the platinum group metals (pgms), which also include Ru, Os, Pt, Rh, and Ir. According to the ACS Green Chemistry Institute,1 Pd has “limited availability…”; the other five are also endangered, given their “rising threat from increased use.” In brief, they are, in one way or another, all at risk. And while neither Os nor even Ru is considered “precious” usually based on cost, both Pt and Pd are certainly “expensive”, while Ir, and especially Rh, are borderline prohibitive, typically being reserved for reactions where catalyst loadings must be very low. During the past few years, the price of Pd has jumped on occasion to >$3000/Troy ounce (vide infra), and even today remains more valued than is Au (<$2000/Troy ounce). What does this suggest regarding the prognosis for pgms even in the short term, let alone the prospects for long term availability? How can we continue today with a “business as usual” mentality, knowing that these particular resources on the planet are finite? Are we not already operating in crisis mode, if only on the basis of price, where palladium may provide, at least on paper, the solution to an important synthetic problem but its use in the lab is simply unaffordable? For many CMOs that make crucial intermediates, that time is already here. What now?
{"title":"On the Sustainability of Palladium in Organic Synthesis: A Perspective","authors":"B. Lipshutz","doi":"10.1595/205651323x16698159435916","DOIUrl":"https://doi.org/10.1595/205651323x16698159435916","url":null,"abstract":"Ask any card-carrying organic chemist which metal reigns supreme today in synthetic organic chemistry and most, if not all, will quickly identify palladium as the clear winner. But this soft, silver-white metal is only one of six that make up the platinum group metals (pgms), which also include Ru, Os, Pt, Rh, and Ir. According to the ACS Green Chemistry Institute,1 Pd has “limited availability…”; the other five are also endangered, given their “rising threat from increased use.” In brief, they are, in one way or another, all at risk. And while neither Os nor even Ru is considered “precious” usually based on cost, both Pt and Pd are certainly “expensive”, while Ir, and especially Rh, are borderline prohibitive, typically being reserved for reactions where catalyst loadings must be very low. During the past few years, the price of Pd has jumped on occasion to >$3000/Troy ounce (vide infra), and even today remains more valued than is Au (<$2000/Troy ounce). What does this suggest regarding the prognosis for pgms even in the short term, let alone the prospects for long term availability? How can we continue today with a “business as usual” mentality, knowing that these particular resources on the planet are finite? Are we not already operating in crisis mode, if only on the basis of price, where palladium may provide, at least on paper, the solution to an important synthetic problem but its use in the lab is simply unaffordable? For many CMOs that make crucial intermediates, that time is already here. What now?","PeriodicalId":14807,"journal":{"name":"Johnson Matthey Technology Review","volume":"1 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67351654","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 : 2022-01-01DOI: 10.1595/205651323x16527144808494
Mehrdad Zarinejad, Sajjad Rimaz, Y. Tong, K. Wada, F. Pahlevani
Dependence of mechanical properties of binary Pt-Rh alloys on valence electron ratio (VER), number valence electrons (ev), and average atomic number of the alloys (Z) are investigated. The alloys have high number of valence electrons (9 ≤ ev ≤ 10) and a wide range of the average atomic number (Z = 45–78). Clear correlations between VER of the alloys and their mechanical properties are found. By increasing the VER of the alloy from 0.13 to 0.20 following the increase of Rh content in the composition, the hardness, elastic modulus, and ultimate tensile strength of the alloy increases. Creep rates of the selected alloys clearly decrease with increasing VER at high temperatures (1500-1700 ℃C), whilst stress rupture time at different temperatures consistently increases because of higher Rh content in the alloy solid solution chemistry. Dependence of mechanical properties on valence electron parameters is discussed with reference to the atomic bonding.
{"title":"Dependence of Mechanical Properties of Platinum-Rhodium Binary Alloys on Valence Electron Parameters","authors":"Mehrdad Zarinejad, Sajjad Rimaz, Y. Tong, K. Wada, F. Pahlevani","doi":"10.1595/205651323x16527144808494","DOIUrl":"https://doi.org/10.1595/205651323x16527144808494","url":null,"abstract":"Dependence of mechanical properties of binary Pt-Rh alloys on valence electron ratio (VER), number valence electrons (ev), and average atomic number of the alloys (Z) are investigated. The alloys have high number of valence electrons (9 ≤ ev ≤ 10) and a wide range of the average atomic number (Z = 45–78). Clear correlations between VER of the alloys and their mechanical properties are found. By increasing the VER of the alloy from 0.13 to 0.20 following the increase of Rh content in the composition, the hardness, elastic modulus, and ultimate tensile strength of the alloy increases. Creep rates of the selected alloys clearly decrease with increasing VER at high temperatures (1500-1700 ℃C), whilst stress rupture time at different temperatures consistently increases because of higher Rh content in the alloy solid solution chemistry. Dependence of mechanical properties on valence electron parameters is discussed with reference to the atomic bonding.","PeriodicalId":14807,"journal":{"name":"Johnson Matthey Technology Review","volume":"1 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67351776","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 : 2022-01-01DOI: 10.1595/205651322x16624692154666
P. Styring
“Advances in Carbon Capture and Utilization” is a multi-author book that is edited by Deepak Pant, Ashok Kumar Nadda, Kamal Kishore Pant and Avinash Kumar Agarwal and published by Springer.
{"title":"“Advances in Carbon Capture and Utilization”","authors":"P. Styring","doi":"10.1595/205651322x16624692154666","DOIUrl":"https://doi.org/10.1595/205651322x16624692154666","url":null,"abstract":"“Advances in Carbon Capture and Utilization” is a multi-author book that is edited by Deepak Pant, Ashok Kumar Nadda, Kamal Kishore Pant and Avinash Kumar Agarwal and published by Springer.","PeriodicalId":14807,"journal":{"name":"Johnson Matthey Technology Review","volume":"1 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67351005","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 : 2022-01-01DOI: 10.1595/205651322x16554704236047
J. Ashcroft, Helen Goddin
Ammonia is a strong candidate as a hydrogen vector and has the flexibility to be used directly as a fuel or decomposed to form pure hydrogen. The format of an ammonia decomposition plant is only starting to emerge, with two types becoming significant: centralised locations feeding into the national gas network, and decentralised units, to supply fuelling stations, the chemical industry, or remote applications. In this paper, we review the aspects critical to decompose ammonia in both cases. While the centralised cracking flowsheet can use equipment standard to current hydrogen production methods, the localised cracking unit requires a more innovative design. Energy and safety considerations may favour low temperature operation for decentralised applications, requiring high activity catalysts, whilst centralised industrial sites may operate at higher temperatures and use a base metal catalyst. Purification to deliver hydrogen suitable for fuel cells is one of the biggest challenges in developing the flowsheet.
{"title":"Centralised and localised hydrogen generation by ammonia decomposition","authors":"J. Ashcroft, Helen Goddin","doi":"10.1595/205651322x16554704236047","DOIUrl":"https://doi.org/10.1595/205651322x16554704236047","url":null,"abstract":"Ammonia is a strong candidate as a hydrogen vector and has the flexibility to be used directly as a fuel or decomposed to form pure hydrogen. The format of an ammonia decomposition plant is only starting to emerge, with two types becoming significant: centralised locations feeding into the national gas network, and decentralised units, to supply fuelling stations, the chemical industry, or remote applications. In this paper, we review the aspects critical to decompose ammonia in both cases. While the centralised cracking flowsheet can use equipment standard to current hydrogen production methods, the localised cracking unit requires a more innovative design. Energy and safety considerations may favour low temperature operation for decentralised applications, requiring high activity catalysts, whilst centralised industrial sites may operate at higher temperatures and use a base metal catalyst. Purification to deliver hydrogen suitable for fuel cells is one of the biggest challenges in developing the flowsheet.","PeriodicalId":14807,"journal":{"name":"Johnson Matthey Technology Review","volume":"1 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67351307","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 : 2022-01-01DOI: 10.1595/205651323x16570342480111
L. Cabri
The native platinum-group elements (PGE), namely, the light PGE (Ru, Rh, and Pd) and the heavy PGE (Os, Ir, and Pt), are important historically, scientifically, and industrially. The scientists who discovered and refined these metals in the 18th and early 19th centuries, besides being chemists, some were also physicians, but all were also knowledgeable of mineralogy. We cannot but be impressed by their achievements because of the complexity of the minerals they studied. The PGE alloys occurred as a fraction of the heavy minerals concentrated from alluvial deposits. Today we can understand why some details of their discovery and mineralogy have not been well understood because of a lack of modern mineralogical studies and misunderstandings of some of the early literature, especially for native palladium and platinum. Though reported widely, highlights of the historical discoveries are assembled in a single paper and discussed with respect to the mineralogy of the samples studied.
{"title":"Discovery of the Six Members of the Platinum Group and Their Mineralogical Characterization","authors":"L. Cabri","doi":"10.1595/205651323x16570342480111","DOIUrl":"https://doi.org/10.1595/205651323x16570342480111","url":null,"abstract":"The native platinum-group elements (PGE), namely, the light PGE (Ru, Rh, and Pd) and the heavy PGE (Os, Ir, and Pt), are important historically, scientifically, and industrially. The scientists who discovered and refined these metals in the 18th and early 19th centuries, besides being chemists, some were also physicians, but all were also knowledgeable of mineralogy. We cannot but be impressed by their achievements because of the complexity of the minerals they studied. The PGE alloys occurred as a fraction of the heavy minerals concentrated from alluvial deposits. Today we can understand why some details of their discovery and mineralogy have not been well understood because of a lack of modern mineralogical studies and misunderstandings of some of the early literature, especially for native palladium and platinum. Though reported widely, highlights of the historical discoveries are assembled in a single paper and discussed with respect to the mineralogy of the samples studied.","PeriodicalId":14807,"journal":{"name":"Johnson Matthey Technology Review","volume":"27 24 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67351342","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 : 2022-01-01DOI: 10.1595/205651323x16601431334489
Abd Baghad, K. Mabrouk
Many additive manufacturing (AM) processes have been developed to fabricate lightweight metal matrix composites (LMMCs) from constituents’ materials. However, the improvement in mechanical properties is significantly affected by the added reinforcing materials in the light metal matrix compared to metallic materials and their alloys. Recent advances in understanding the selecting criteria and effect of the reinforcement, preparation methods, and additive manufacturing process on the properties of LMMCs are summarized. The preparation methods of particle-reinforced LMMCs include ex-situ and in-situ synthesizing. The effect of various reinforcement and AM processes such as powder bed fusion (PBF) processes and direct energy deposition (DED) processes on the mechanical properties of LMMCs parts are discussed.
{"title":"A Brief Review on Additive Manufacturing Processes for Lightweight Metal Matrix Composites","authors":"Abd Baghad, K. Mabrouk","doi":"10.1595/205651323x16601431334489","DOIUrl":"https://doi.org/10.1595/205651323x16601431334489","url":null,"abstract":"Many additive manufacturing (AM) processes have been developed to fabricate lightweight metal matrix composites (LMMCs) from constituents’ materials. However, the improvement in mechanical properties is significantly affected by the added reinforcing materials in the light metal matrix compared to metallic materials and their alloys. Recent advances in understanding the selecting criteria and effect of the reinforcement, preparation methods, and additive manufacturing process on the properties of LMMCs are summarized. The preparation methods of particle-reinforced LMMCs include ex-situ and in-situ synthesizing. The effect of various reinforcement and AM processes such as powder bed fusion (PBF) processes and direct energy deposition (DED) processes on the mechanical properties of LMMCs parts are discussed.","PeriodicalId":14807,"journal":{"name":"Johnson Matthey Technology Review","volume":"1 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67351442","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 : 2022-01-01DOI: 10.1595/205651323x16653975448311
A. K. Maddheshiya, S. Singh, Devraj Singh, R. Yadav, P. S. Yadav
The propagation of ultrasonic wave in the hexagonal closed packed (hcp) structured lanthanide metal titanium (Ti) has been investigated in temperature range 300-1000K. For this, initially the higher-order elastic constants (SOECs and TOECs) have been computed using Lennard–Jones interaction potential model. With the help of SOECs, other elastic moduli such as Young’s modulus (Y), bulk modulus (B), shear modulus (G), Poisson’s ratio (σ), and Pugh’s ratio (B/G) have been computed for Ti metal using Voigt–Reuss–Hill (VRH) approximation. Later on, orientation dependent three types of ultrasonic velocities including Debye average velocities have been evaluated utilizing calculated values of SOECs and density of Ti in the same temperature range. Thermophysical properties such as lattice thermal conductivity, thermal relaxation time, thermal energy density, specific heat at constant volume and acoustic coupling constant of Ti have been also evaluated at same physical conditions. The ultrasonic attenuation due to phonon-phonon interaction is most significant in chosen physical conditions. The ultrasonic properties have been correlated with thermophysical properties to understand the microstructural features and nature of the material.
{"title":"Non-Linear Thermophysical Behaviour of Transition Metal Titanium","authors":"A. K. Maddheshiya, S. Singh, Devraj Singh, R. Yadav, P. S. Yadav","doi":"10.1595/205651323x16653975448311","DOIUrl":"https://doi.org/10.1595/205651323x16653975448311","url":null,"abstract":"The propagation of ultrasonic wave in the hexagonal closed packed (hcp) structured lanthanide metal titanium (Ti) has been investigated in temperature range 300-1000K. For this, initially the higher-order elastic constants (SOECs and TOECs) have been computed using Lennard–Jones interaction potential model. With the help of SOECs, other elastic moduli such as Young’s modulus (Y), bulk modulus (B), shear modulus (G), Poisson’s ratio (σ), and Pugh’s ratio (B/G) have been computed for Ti metal using Voigt–Reuss–Hill (VRH) approximation. Later on, orientation dependent three types of ultrasonic velocities including Debye average velocities have been evaluated utilizing calculated values of SOECs and density of Ti in the same temperature range. Thermophysical properties such as lattice thermal conductivity, thermal relaxation time, thermal energy density, specific heat at constant volume and acoustic coupling constant of Ti have been also evaluated at same physical conditions. The ultrasonic attenuation due to phonon-phonon interaction is most significant in chosen physical conditions. The ultrasonic properties have been correlated with thermophysical properties to understand the microstructural features and nature of the material.","PeriodicalId":14807,"journal":{"name":"Johnson Matthey Technology Review","volume":"1 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67351634","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 : 2022-01-01DOI: 10.1595/205651322x16493249558666
A. Daisley, J. Hargreaves
Driven by the desire to develop novel catalyst formulations which are applicable for localised, more sustainable routes, the area of heterogeneously catalysed ammonia synthesis has attracted much attention in the academic literature in recent times. One of the key incentives for this has been the idea that ammonia synthesis for the production of synthetic fertiliser can be achieved on, for example, a farm close to its point of application with the required hydrogen feedstream being derived from sustainable sources such as electrolysis of water accomplished using electricity produced using wind turbines or solar energy sources. Further drivers are the possible application of ammonia as a non-fossil based fuel and also as a means to indirectly store intermittent over-supply of sustainably derived electricity. In the literature, the energy intensive nature of the Haber Bosch Process, frequently quoted to be 1-2% of global energy demand, and its CO2 footprint, stated to comprise 2.5% of fossil fuel based emissions, are statistics that are frequently quoted in justification for the search for new routes to ammonia production [1,2]. However, due recognition has to be given to the highly efficient integration of the Haber Bosch Process as currently operated. In relation to this, large scale synthesis of ammonia is highly optimised and it can be credited with the sustenance of ca 40% of the global population. These considerations, coupled to the recently reported UK CO2 supply chain shortage, related to a reduction in commercial fertiliser production [3], underline the importance of the highly integrated nature of the process.
{"title":"Nitrides, Hydrides and Carbides as Alternative Heterogeneous Catalysis for Ammonia Synthesis: A Brief Overview","authors":"A. Daisley, J. Hargreaves","doi":"10.1595/205651322x16493249558666","DOIUrl":"https://doi.org/10.1595/205651322x16493249558666","url":null,"abstract":"Driven by the desire to develop novel catalyst formulations which are applicable for localised, more sustainable routes, the area of heterogeneously catalysed ammonia synthesis has attracted much attention in the academic literature in recent times. One of the key incentives for this has been the idea that ammonia synthesis for the production of synthetic fertiliser can be achieved on, for example, a farm close to its point of application with the required hydrogen feedstream being derived from sustainable sources such as electrolysis of water accomplished using electricity produced using wind turbines or solar energy sources. Further drivers are the possible application of ammonia as a non-fossil based fuel and also as a means to indirectly store intermittent over-supply of sustainably derived electricity. In the literature, the energy intensive nature of the Haber Bosch Process, frequently quoted to be 1-2% of global energy demand, and its CO2 footprint, stated to comprise 2.5% of fossil fuel based emissions, are statistics that are frequently quoted in justification for the search for new routes to ammonia production [1,2]. However, due recognition has to be given to the highly efficient integration of the Haber Bosch Process as currently operated. In relation to this, large scale synthesis of ammonia is highly optimised and it can be credited with the sustenance of ca 40% of the global population. These considerations, coupled to the recently reported UK CO2 supply chain shortage, related to a reduction in commercial fertiliser production [3], underline the importance of the highly integrated nature of the process.","PeriodicalId":14807,"journal":{"name":"Johnson Matthey Technology Review","volume":"1 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67350886","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 : 2022-01-01DOI: 10.1595/205651322x16529612227119
Jasmine A. Clayton, R. Walton
We review recent research into oxides of platinum-group metals (PGMs), in particular those of ruthenium and iridium, for use as electrocatalysts for the oxygen evolution reaction. These are used in membrane electrode assemblies in devices such as electrolysers, for water splitting to generate hydrogen as fuel, and in fuel cells where they provide a buffer against carbon corrosion. In these situations, proton-exchange membrane layers are used, and highly acid-resilient electrocatalyst materials are required. The range of structure types investigated includes perovskites, pyrochlores and hexagonal perovskite-like phases, where the PGM is partnered by base metals in complex chemical compositions. The role of chemical synthesis in the discovery of new oxide compositions is emphasised, particularly to yield powders for processing into membrane electrode assemblies. We highlight emerging work that shows how leaching of the base metals from the multinary compositions occurs during operation to yield active PGM-oxide phases, and how attempts to correlate stability with crystal structure have been made. Implications of these discoveries for the balance of activity and stability needed for effective electrocatalysis in real devices are discussed.
{"title":"Development of New Mixed-Metal Ruthenium and Iridium Oxides as Electrocatalysts for Oxygen Evolution","authors":"Jasmine A. Clayton, R. Walton","doi":"10.1595/205651322x16529612227119","DOIUrl":"https://doi.org/10.1595/205651322x16529612227119","url":null,"abstract":"We review recent research into oxides of platinum-group metals (PGMs), in particular those of ruthenium and iridium, for use as electrocatalysts for the oxygen evolution reaction. These are used in membrane electrode assemblies in devices such as electrolysers, for water splitting to generate hydrogen as fuel, and in fuel cells where they provide a buffer against carbon corrosion. In these situations, proton-exchange membrane layers are used, and highly acid-resilient electrocatalyst materials are required. The range of structure types investigated includes perovskites, pyrochlores and hexagonal perovskite-like phases, where the PGM is partnered by base metals in complex chemical compositions. The role of chemical synthesis in the discovery of new oxide compositions is emphasised, particularly to yield powders for processing into membrane electrode assemblies. We highlight emerging work that shows how leaching of the base metals from the multinary compositions occurs during operation to yield active PGM-oxide phases, and how attempts to correlate stability with crystal structure have been made. Implications of these discoveries for the balance of activity and stability needed for effective electrocatalysis in real devices are discussed.","PeriodicalId":14807,"journal":{"name":"Johnson Matthey Technology Review","volume":"1 1","pages":""},"PeriodicalIF":2.3,"publicationDate":"2022-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"67351191","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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