Carson Ziemke, Ha M. Nguyen, Sebastián Amaya-Roncancio, John M. Gahl, Yangchuan Xing, Thomas Heitmann, Carlos Wexler
The monoclinic (m-LBO) and tetragonal (t-LBO) polymorphs of the lithium metaborate (LiBO2) material have significant potentials for technological applications such as solid electrolytes and electrode coatings of lithium-ion batteries. While comparative studies of electronic, ionic, and photonic properties in these polymorphs exist, the role of lattice vacancies on lithium-ion transport in these polymorphs remains unclear. In this study, we employed density functional theory (DFT) to investigate the formation of lattice vacancies and their impacts on the lattice structure, electronic properties, and lithium-ion migration energy barrier (Em) in both m-LBO and t-LBO. Our DFT results reveal that boron and oxygen vacancies affect the lithium-ion transport in both the polymorphs, but in different ways. While oxygen vacancies lower Em in m-LBO, they increase it in t-LBO. In contrast, boron vacancies significantly reduce Em in both m-LBO and t-LBO, leading to a remarkably-enhanced ionic conductivity in both the polymorphs. This enhancement in the ionic conductivity could be due to favorable alterations in the crystal and electronic structures caused by the presence of boron vacancies. This improvement suggests a potential strategy for improving the ionic conductivity of the LiBO2 material through boron vacancy generation. For example, boron vacancies might be created in the lattice structures of the LiBO2 material using a controlled neutron irradiation.
{"title":"Formation of Lattice Vacancies and their Effects on Lithium-ion Transport in LiBO2 Crystals: Comparative Ab Initio Studies","authors":"Carson Ziemke, Ha M. Nguyen, Sebastián Amaya-Roncancio, John M. Gahl, Yangchuan Xing, Thomas Heitmann, Carlos Wexler","doi":"10.1039/d4ta05713a","DOIUrl":"https://doi.org/10.1039/d4ta05713a","url":null,"abstract":"The monoclinic (m-LBO) and tetragonal (t-LBO) polymorphs of the lithium metaborate (LiBO<small><sub>2</sub></small>) material have significant potentials for technological applications such as solid electrolytes and electrode coatings of lithium-ion batteries. While comparative studies of electronic, ionic, and photonic properties in these polymorphs exist, the role of lattice vacancies on lithium-ion transport in these polymorphs remains unclear. In this study, we employed density functional theory (DFT) to investigate the formation of lattice vacancies and their impacts on the lattice structure, electronic properties, and lithium-ion migration energy barrier (<em>E</em><small><sub>m</sub></small>) in both m-LBO and t-LBO. Our DFT results reveal that boron and oxygen vacancies affect the lithium-ion transport in both the polymorphs, but in different ways. While oxygen vacancies lower <em>E</em><small><sub>m</sub></small> in m-LBO, they increase it in t-LBO. In contrast, boron vacancies significantly reduce <em>E</em><small><sub>m</sub></small> in both m-LBO and t-LBO, leading to a remarkably-enhanced ionic conductivity in both the polymorphs. This enhancement in the ionic conductivity could be due to favorable alterations in the crystal and electronic structures caused by the presence of boron vacancies. This improvement suggests a potential strategy for improving the ionic conductivity of the LiBO<small><sub>2</sub></small> material through boron vacancy generation. For example, boron vacancies might be created in the lattice structures of the LiBO<small><sub>2</sub></small> material using a controlled neutron irradiation.","PeriodicalId":82,"journal":{"name":"Journal of Materials Chemistry A","volume":"5 1","pages":""},"PeriodicalIF":11.9,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142809295","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Donald R. Inns, Megan Carr, Mounib Bahri, Ajay Tomer, Troy D. Manning, Nigel Browning, Simon A. Kondrat, John B. Claridge, Alexandros P. Katsoulidis, Matthew J. Rosseinsky
The catalytic hydrogenolysis process offers the selective production of high-value liquid alkanes from waste polymers. Herein, through normalisation of Ni structure, Ni mass and density, and CeO2 crystallite size, the importance of CeO2 nanocube morphology in the hydrogenolysis of polypropylene (Mw = 12 000 g mol−1; Mn = 5000 g mol−1) over Ni/CeO2 catalysts was determined. High liquid productivities (65.9–70.9 gliquid gNi−1 h−1) and low methane yields (10%) were achieved over two different Ni/CeO2 catalysts after 16 h reaction due to the high activity and internal scission selectivity of the supported ultrafine Ni particles (<1.3 nm). However, the Ni/CeO2 nanocube catalyst exhibited higher C–C scission rates (838.1 mmol gNi−1 h−1) than a standard benchmark mixed shape Ni/CeO2 catalyst (480.3 mmol gNi−1 h−1) and represents a 75% increase in depolymerisation activity. This led to shorter hydrocarbon chains achieved by the nanocube catalyst (Mw = 2786 g mol−1; Mn = 1442 g mol−1) when compared to the mixed shape catalyst (Mw = 4599 g mol−1; Mn = 2530 g mol−1). The enhanced C–C scission rate of the nanocube catalyst was determined to arise from a combination of improved H-storage and favourable basic properties, with higher weak basic site density key to facilitate a greater degree of hydrocarbon chain adsorption.
{"title":"Elucidating the effect of nanocube support morphology on the hydrogenolysis of polypropylene over Ni/CeO2 catalysts","authors":"Donald R. Inns, Megan Carr, Mounib Bahri, Ajay Tomer, Troy D. Manning, Nigel Browning, Simon A. Kondrat, John B. Claridge, Alexandros P. Katsoulidis, Matthew J. Rosseinsky","doi":"10.1039/d4ta08111k","DOIUrl":"https://doi.org/10.1039/d4ta08111k","url":null,"abstract":"The catalytic hydrogenolysis process offers the selective production of high-value liquid alkanes from waste polymers. Herein, through normalisation of Ni structure, Ni mass and density, and CeO<small><sub>2</sub></small> crystallite size, the importance of CeO<small><sub>2</sub></small> nanocube morphology in the hydrogenolysis of polypropylene (<em>M</em><small><sub>w</sub></small> = 12 000 g mol<small><sup>−1</sup></small>; <em>M</em><small><sub>n</sub></small> = 5000 g mol<small><sup>−1</sup></small>) over Ni/CeO<small><sub>2</sub></small> catalysts was determined. High liquid productivities (65.9–70.9 g<small><sub>liquid</sub></small> g<small><sub>Ni</sub></small><small><sup>−1</sup></small> h<small><sup>−1</sup></small>) and low methane yields (10%) were achieved over two different Ni/CeO<small><sub>2</sub></small> catalysts after 16 h reaction due to the high activity and internal scission selectivity of the supported ultrafine Ni particles (<1.3 nm). However, the Ni/CeO<small><sub>2</sub></small> nanocube catalyst exhibited higher C–C scission rates (838.1 mmol g<small><sub>Ni</sub></small><small><sup>−1</sup></small> h<small><sup>−1</sup></small>) than a standard benchmark mixed shape Ni/CeO<small><sub>2</sub></small> catalyst (480.3 mmol g<small><sub>Ni</sub></small><small><sup>−1</sup></small> h<small><sup>−1</sup></small>) and represents a 75% increase in depolymerisation activity. This led to shorter hydrocarbon chains achieved by the nanocube catalyst (<em>M</em><small><sub>w</sub></small> = 2786 g mol<small><sup>−1</sup></small>; <em>M</em><small><sub>n</sub></small> = 1442 g mol<small><sup>−1</sup></small>) when compared to the mixed shape catalyst (<em>M</em><small><sub>w</sub></small> = 4599 g mol<small><sup>−1</sup></small>; <em>M</em><small><sub>n</sub></small> = 2530 g mol<small><sup>−1</sup></small>). The enhanced C–C scission rate of the nanocube catalyst was determined to arise from a combination of improved H-storage and favourable basic properties, with higher weak basic site density key to facilitate a greater degree of hydrocarbon chain adsorption.","PeriodicalId":82,"journal":{"name":"Journal of Materials Chemistry A","volume":"21 1","pages":""},"PeriodicalIF":11.9,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797306","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Temperature fluctuations caused by sunlight represent a form of low-quality thermal energy that is generally insufficient for driving chemical reactions. Here, we designed a ZnO-MXene (Ti3C2) heterostructure catalyst, which can harvest solar near-infrared (NIR) energy to drive the sluggish ammonia production reaction using water and N2 as the feedstock. Our research confirmed that ammonia was produced through a pyroelectric process, rather than a photocatalytic process. The ZnO-MXene heterostructure with ~ 20 wt.% of Ti3C2 exhibited a 6.5-folder improvement in activity compared to bare ZnO. The Ti3C2 not only harvests NIR energy to heat up the pyroelectric ZnO, but also traps the pyro electrons from ZnO and co-catalyzes the reduction of N2 to ammonia. This work offers a novel strategy for ammonia production utilizing the abundant solar NIR energy under ambient conditions.
{"title":"Near-infrared driven N2 fixation on ZnO-MXene (Ti3C2) heterostructures through pyroelectric catalysis","authors":"Chunzheng Wu, Jingyuan Lin, Zhuojiong Xie, Xuan Kai, Xiao Yu, Zhenyu Yan, Jinwei Fang, Shanliang Chen, Jianzhong Guo, Wei Wang, Fengping Peng","doi":"10.1039/d4ta07166b","DOIUrl":"https://doi.org/10.1039/d4ta07166b","url":null,"abstract":"Temperature fluctuations caused by sunlight represent a form of low-quality thermal energy that is generally insufficient for driving chemical reactions. Here, we designed a ZnO-MXene (Ti3C2) heterostructure catalyst, which can harvest solar near-infrared (NIR) energy to drive the sluggish ammonia production reaction using water and N2 as the feedstock. Our research confirmed that ammonia was produced through a pyroelectric process, rather than a photocatalytic process. The ZnO-MXene heterostructure with ~ 20 wt.% of Ti3C2 exhibited a 6.5-folder improvement in activity compared to bare ZnO. The Ti3C2 not only harvests NIR energy to heat up the pyroelectric ZnO, but also traps the pyro electrons from ZnO and co-catalyzes the reduction of N2 to ammonia. This work offers a novel strategy for ammonia production utilizing the abundant solar NIR energy under ambient conditions.","PeriodicalId":82,"journal":{"name":"Journal of Materials Chemistry A","volume":"15 1","pages":""},"PeriodicalIF":11.9,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study presents a comprehensive investigation into the synthesis and photoelectrochemical performance of delafossite AgFeO2 nanosheets, modulated through controlled hydrothermal conditions. The nanosheets' dimensions, specifically width and thickness, were tailored to examine the influence of surface polarization on photocatalytic efficacy. Notably, an increase in nanosheet width, while maintaining a constant thickness, corresponded to a significant rise in photocurrent density, peaking at 15.6 μA/cm² for AgFeO2 nanosheets with smaller thickness and larger surface area of (001) facet under optimized conditions. This enhancement is attributed to the increased intensity and contribution of the built-in electric field on the (001) polar facet, thus facilitating improved effective separation and rapid transfer of photogenerated electron-hole pairs. The introduction of interstitial oxygen and an external magnetic field further demonstrated the potential of multiple polarization coupling—spin, macro, and surface—to maximize the photoelectrochemical potential of AgFeO2 nanosheets. These findings underscore the critical role of surface polarization in optimizing the photoelectrochemical performance of AgFeO2 nanosheets and highlight the potential for nanoscale design in developing advanced photocathodes. The findings pave the way for future research aimed at refining synthesis methods and exploiting the synergistic effects of multiple polarizations for enhanced solar energy conversion efficiencies.
{"title":"Unraveling Surface Polarization in Hydrothermally Derived AgFeO2 Nanosheets for Enhanced Photoelectrochemical Performance","authors":"Shui-Miao Yu, Xu-Dong Dong, Zong-Yan Zhao","doi":"10.1039/d4ta06367h","DOIUrl":"https://doi.org/10.1039/d4ta06367h","url":null,"abstract":"This study presents a comprehensive investigation into the synthesis and photoelectrochemical performance of delafossite AgFeO2 nanosheets, modulated through controlled hydrothermal conditions. The nanosheets' dimensions, specifically width and thickness, were tailored to examine the influence of surface polarization on photocatalytic efficacy. Notably, an increase in nanosheet width, while maintaining a constant thickness, corresponded to a significant rise in photocurrent density, peaking at 15.6 μA/cm² for AgFeO2 nanosheets with smaller thickness and larger surface area of (001) facet under optimized conditions. This enhancement is attributed to the increased intensity and contribution of the built-in electric field on the (001) polar facet, thus facilitating improved effective separation and rapid transfer of photogenerated electron-hole pairs. The introduction of interstitial oxygen and an external magnetic field further demonstrated the potential of multiple polarization coupling—spin, macro, and surface—to maximize the photoelectrochemical potential of AgFeO2 nanosheets. These findings underscore the critical role of surface polarization in optimizing the photoelectrochemical performance of AgFeO2 nanosheets and highlight the potential for nanoscale design in developing advanced photocathodes. The findings pave the way for future research aimed at refining synthesis methods and exploiting the synergistic effects of multiple polarizations for enhanced solar energy conversion efficiencies.","PeriodicalId":82,"journal":{"name":"Journal of Materials Chemistry A","volume":"103 1","pages":""},"PeriodicalIF":11.9,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797307","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The electrochemical CO2 reduction reaction (CO2RR) provides a means for producing ethylene, but its selectivity and stability still need further improvement. Therefore, the development of high-performance electrocatalysts is particularly important. Here, we designed a catalyst CuxOy/CN with a nitrogen-doped carbon (CN) coating, which was prepared by pyrolysis of nitrogen-containing Cu-based MOF with high porosity, using it as a sacrificial template. For CO2RR, the CuxOy/CN catalyst demonstrates a very good ethylene selectivity, achieving a Faradaic efficiency (FE) of 44% at a current density of 500 mA cm-2. Impressively, the CuxOy/CN catalyst has a higher partial current density for ethylene in the CO2RR process, reaching about 220 mA cm-2, compared with other catalysts recorded in the literature. After CO2RR, the CuxOy/CN catalyst exposed the Cu(100) facet and the Cu+/Cu0 interface, which favored the generation of ethylene. Operando Raman spectroscopy indicates that the CN coating efficiently stabilizes Cu+ species under CO2 electroreduction conditions. Density functional theory (DFT) calculations demonstrate that the CN coating stabilizes *CO intermediates. The CN-coated Cu+/Cu0 interface sites on the CuxOy/CN catalyst enhance *CO adsorption, increase *CO coverage, promote C−C coupling, and thus improve ethylene selectivity and stability.
{"title":"Stabilizing *CO intermediate on nitrogen-doped carbon-coated CuxOy derived from metal-organic framework for enhanced electrochemical CO2-to-ethylene","authors":"Na Zhang, Yunlong Zhang","doi":"10.1039/d4ta06722c","DOIUrl":"https://doi.org/10.1039/d4ta06722c","url":null,"abstract":"The electrochemical CO<small><sub>2</sub></small> reduction reaction (CO<small><sub>2</sub></small>RR) provides a means for producing ethylene, but its selectivity and stability still need further improvement. Therefore, the development of high-performance electrocatalysts is particularly important. Here, we designed a catalyst CuxOy/CN with a nitrogen-doped carbon (CN) coating, which was prepared by pyrolysis of nitrogen-containing Cu-based MOF with high porosity, using it as a sacrificial template. For CO<small><sub>2</sub></small>RR, the CuxOy/CN catalyst demonstrates a very good ethylene selectivity, achieving a Faradaic efficiency (FE) of 44% at a current density of 500 mA cm<small><sup>-2</sup></small>. Impressively, the CuxOy/CN catalyst has a higher partial current density for ethylene in the CO2RR process, reaching about 220 mA cm<small><sup>-2</sup></small>, compared with other catalysts recorded in the literature. After CO2RR, the CuxOy/CN catalyst exposed the Cu(100) facet and the Cu<small><sup>+</sup></small>/Cu<small><sup>0</sup></small> interface, which favored the generation of ethylene. Operando Raman spectroscopy indicates that the CN coating efficiently stabilizes Cu<small><sup>+</sup></small> species under CO<small><sub>2</sub></small> electroreduction conditions. Density functional theory (DFT) calculations demonstrate that the CN coating stabilizes *CO intermediates. The CN-coated Cu<small><sup>+</sup></small>/Cu<small><sup>0</sup></small> interface sites on the CuxOy/CN catalyst enhance *CO adsorption, increase *CO coverage, promote C−C coupling, and thus improve ethylene selectivity and stability.","PeriodicalId":82,"journal":{"name":"Journal of Materials Chemistry A","volume":"28 1","pages":""},"PeriodicalIF":11.9,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Nitesh Choudhary, Akshay Tomar, Shakshi Bhardwaj, Jakub Cwiertnia, Dominik Just, Dawid Janas, Ramesh Chandra, Pradip Kumar Maji
Renewable and sustainable biomass nanomaterials have garnered significant interest in developing green and renewable supercapacitor devices with cost-effective, flexible, and lightweight features. Biomass-derived cellulose-based composites are favorable as electrode materials due to their renewability, hydrophilicity, high aspect ratio, biodegradability, low weight, high surface area, and impressive mechanical behavior. Furthermore, there is growing scientific interest in biomass-derived cellulose composite electrode materials along with other conductive materials for supercapacitors, as they exhibit high conductivity and favorable electrochemical properties. In light of this, the goal of this review is to investigate the state of the art and the historical development of cellulose composite materials in supercapacitors, with a particular emphasis on the influence of construction and chemical composition on the corresponding flexible electrodes' electrochemical behavior. Various cellulose composite electrode materials' effectiveness in developing sustainable energy storage devices and artificial intelligence and machine learning is emphasized. Subsequently, the importance of modulated dynamic simulation and artificial intelligence and machine learning approach aspects in cellulose-based electrodes is also discussed. Lastly, the review concludes with a brief overview of challenges, and future perspectives and examines the discrepancy between the results obtained in the lab and practical applications of these cellulose composite materials made from biomass, while also proposing feasible approaches for further improvement.
{"title":"Advancements in Biomass-Derived Cellulose Composite Electrodes for Supercapacitors: A Review","authors":"Nitesh Choudhary, Akshay Tomar, Shakshi Bhardwaj, Jakub Cwiertnia, Dominik Just, Dawid Janas, Ramesh Chandra, Pradip Kumar Maji","doi":"10.1039/d4ta05470a","DOIUrl":"https://doi.org/10.1039/d4ta05470a","url":null,"abstract":"Renewable and sustainable biomass nanomaterials have garnered significant interest in developing green and renewable supercapacitor devices with cost-effective, flexible, and lightweight features. Biomass-derived cellulose-based composites are favorable as electrode materials due to their renewability, hydrophilicity, high aspect ratio, biodegradability, low weight, high surface area, and impressive mechanical behavior. Furthermore, there is growing scientific interest in biomass-derived cellulose composite electrode materials along with other conductive materials for supercapacitors, as they exhibit high conductivity and favorable electrochemical properties. In light of this, the goal of this review is to investigate the state of the art and the historical development of cellulose composite materials in supercapacitors, with a particular emphasis on the influence of construction and chemical composition on the corresponding flexible electrodes' electrochemical behavior. Various cellulose composite electrode materials' effectiveness in developing sustainable energy storage devices and artificial intelligence and machine learning is emphasized. Subsequently, the importance of modulated dynamic simulation and artificial intelligence and machine learning approach aspects in cellulose-based electrodes is also discussed. Lastly, the review concludes with a brief overview of challenges, and future perspectives and examines the discrepancy between the results obtained in the lab and practical applications of these cellulose composite materials made from biomass, while also proposing feasible approaches for further improvement.","PeriodicalId":82,"journal":{"name":"Journal of Materials Chemistry A","volume":"4 1","pages":""},"PeriodicalIF":11.9,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Metal-free catalysts offer a desirable alternative to traditional metal-based electrocatalysts. However, it remains challenging to improve the catalytic performance of metal-free catalysts to be as promising as that of metal-based materials. Herein, a polymer-assisted method followed by pyrolysis treatment was employed to synthesize nitrogen (N)-doped porous carbon nanoflowers with nanosheet subunits. Leveraging the unique geometry structure and abundant pyridinic-N active sites, the optimized catalyst exhibits a good half-wave potential of 0.85 V versus reversible hydrogen electrode (vs RHE) and long-term stability with only 17.0 mV negative shift of the half-wave potential after 10000 cyclic voltammetry cycles in alkaline electrolyte. This research presents a viable strategy for advancing metal-free electrocatalysts.
{"title":"A Highly Efficient Metal-free Electrocatalyst of Nitrogen-doped Porous Carbon Nanoflowers toward Oxygen Electroreduction","authors":"Xiaoli Fan, Yingying Zhang, Longlong Fan, Qinghong Geng, Wei Zhu, Esmail Doustkhah, Cuiling Li","doi":"10.1039/d4ta07178f","DOIUrl":"https://doi.org/10.1039/d4ta07178f","url":null,"abstract":"Metal-free catalysts offer a desirable alternative to traditional metal-based electrocatalysts. However, it remains challenging to improve the catalytic performance of metal-free catalysts to be as promising as that of metal-based materials. Herein, a polymer-assisted method followed by pyrolysis treatment was employed to synthesize nitrogen (N)-doped porous carbon nanoflowers with nanosheet subunits. Leveraging the unique geometry structure and abundant pyridinic-N active sites, the optimized catalyst exhibits a good half-wave potential of 0.85 V versus reversible hydrogen electrode (vs RHE) and long-term stability with only 17.0 mV negative shift of the half-wave potential after 10000 cyclic voltammetry cycles in alkaline electrolyte. This research presents a viable strategy for advancing metal-free electrocatalysts.","PeriodicalId":82,"journal":{"name":"Journal of Materials Chemistry A","volume":"4 1","pages":""},"PeriodicalIF":11.9,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797348","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Sabi William Konsago, Katarina Žiberna, Aleksander Matavž, Barnik Mandal, Sebastjan Glinsek, Geoff L. Brennecka, Hana Uršič, Barbara Malic
Manganese-doped 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 (BZT–BCT) ferroelectric thin films deposited on platinized sapphire substrates by chemical solution deposition and multistep-annealed at 850 °C, are investigated. The 100 nm and 340 nm thick films are crack-free and have columnar microstructures with average lateral grain sizes of 58 nm and 92 nm, respectively. The 340 nm thick films exhibit a relative permittivity of about 820 at 1 kHz and room temperature, about 60 % higher than the thinner films, which is attributed to the dielectric grain size effect. The thinner films exhibit a larger coercive field and remanent polarization of about 110 kV∙cm-1 and 6 μC∙cm-2 respectively, at 1 MV∙cm-1 compared to 45 kV∙cm-1 and 4 μC∙cm-2 for the thicker films. The 340 nm thick films exhibit a maximum polarization of about 47 μC∙cm-2 at 3.5 MV∙cm-1 and slim polarization loops, resulting in high energy storage properties with 46 J∙cm-3 of recoverable energy storage density and 89 % energy storage efficiency.
{"title":"High Energy Storage Density and Efficiency of 0.5Ba(Zr0.2Ti0.8)O3-0.5(Ba0.7Ca0.3)TiO3 Thin Films on Platinized Sapphire Substrates","authors":"Sabi William Konsago, Katarina Žiberna, Aleksander Matavž, Barnik Mandal, Sebastjan Glinsek, Geoff L. Brennecka, Hana Uršič, Barbara Malic","doi":"10.1039/d4ta05675b","DOIUrl":"https://doi.org/10.1039/d4ta05675b","url":null,"abstract":"Manganese-doped 0.5Ba(Zr<small><sub>0.2</sub></small>Ti<small><sub>0.8</sub></small>)O<small><sub>3</sub></small>-0.5(Ba<small><sub>0.7</sub></small>Ca<small><sub>0.3</sub></small>)TiO<small><sub>3</sub></small> (BZT–BCT) ferroelectric thin films deposited on platinized sapphire substrates by chemical solution deposition and multistep-annealed at 850 °C, are investigated. The 100 nm and 340 nm thick films are crack-free and have columnar microstructures with average lateral grain sizes of 58 nm and 92 nm, respectively. The 340 nm thick films exhibit a relative permittivity of about 820 at 1 kHz and room temperature, about 60 % higher than the thinner films, which is attributed to the dielectric grain size effect. The thinner films exhibit a larger coercive field and remanent polarization of about 110 kV∙cm<small><sup>-1</sup></small> and 6 μC∙cm<small><sup>-2</sup></small> respectively, at 1 MV∙cm<small><sup>-1</sup></small> compared to 45 kV∙cm<small><sup>-1</sup></small> and 4 μC∙cm<small><sup>-2</sup></small> for the thicker films. The 340 nm thick films exhibit a maximum polarization of about 47 μC∙cm<small><sup>-2</sup></small> at 3.5 MV∙cm<small><sup>-1</sup></small> and slim polarization loops, resulting in high energy storage properties with 46 J∙cm<small><sup>-3</sup></small> of recoverable energy storage density and 89 % energy storage efficiency.","PeriodicalId":82,"journal":{"name":"Journal of Materials Chemistry A","volume":"27 1","pages":""},"PeriodicalIF":11.9,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142809294","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Marjan Bele, Blaž Tomc, Azeezulla Nazrulla Mohammed, Primož Šket, Matjaž Finšgar, Angelja Kjara Šurca, Ana Rebeka Kamšek, Martin Šala, Jan Šiler Hudoklin, Matej Huš, Blaž Likozar, Nejc Hodnik
As electrochemical CO2 reduction (ECR) nears industrialisation levels, addressing the uncontrolled stability, restructuring, and deactivation of copper (Cu) catalysts during operation becomes as crucial as achieving high activity and selectivity for a single product. This study used a high-surface area Cu catalyst that exhibited changes in ECR product selectivity over prolonged operation. The detection of dissolved Cu species during electrolysis confirmed an intermediates-mediated Cu dissolution mechanism at ECR potentials (-0.8 to -1.1 V vs. reversible hydrogen electrode). The findings suggest that the electrodeposition of dissolved Cu species is biased towards Cu catalyst sites with lower reaction intermediates coverage, e.g. adsorbed CO (*CO). A dynamic equilibrium between dissolution and subsequent selective redeposition gradually led to morphological restructuring, resulting in a shift in selectivity away from ECR and towards hydrogen production. With the obtained extensive experimental results, theoretical modelling, and literature data, four interconnected parameters governing restructuring and selectivity shifts were recognised: (i) size and (ii) crystallographic orientation of facets of the nanoparticles, (iii) *CO coverage and (iv) CObridge vs. COatop ratio.
{"title":"Deactivation of Copper Electrocatalysts During CO2 Reduction Occurs via Dissolution and Selective Redeposition Mechanism","authors":"Marjan Bele, Blaž Tomc, Azeezulla Nazrulla Mohammed, Primož Šket, Matjaž Finšgar, Angelja Kjara Šurca, Ana Rebeka Kamšek, Martin Šala, Jan Šiler Hudoklin, Matej Huš, Blaž Likozar, Nejc Hodnik","doi":"10.1039/d4ta06466f","DOIUrl":"https://doi.org/10.1039/d4ta06466f","url":null,"abstract":"As electrochemical CO2 reduction (ECR) nears industrialisation levels, addressing the uncontrolled stability, restructuring, and deactivation of copper (Cu) catalysts during operation becomes as crucial as achieving high activity and selectivity for a single product. This study used a high-surface area Cu catalyst that exhibited changes in ECR product selectivity over prolonged operation. The detection of dissolved Cu species during electrolysis confirmed an intermediates-mediated Cu dissolution mechanism at ECR potentials (-0.8 to -1.1 V vs. reversible hydrogen electrode). The findings suggest that the electrodeposition of dissolved Cu species is biased towards Cu catalyst sites with lower reaction intermediates coverage, e.g. adsorbed CO (*CO). A dynamic equilibrium between dissolution and subsequent selective redeposition gradually led to morphological restructuring, resulting in a shift in selectivity away from ECR and towards hydrogen production. With the obtained extensive experimental results, theoretical modelling, and literature data, four interconnected parameters governing restructuring and selectivity shifts were recognised: (i) size and (ii) crystallographic orientation of facets of the nanoparticles, (iii) *CO coverage and (iv) CObridge vs. COatop ratio.","PeriodicalId":82,"journal":{"name":"Journal of Materials Chemistry A","volume":"4 1","pages":""},"PeriodicalIF":11.9,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mingming Hua, Yang Ding, Chunxiao Lv, Ning Han, Kaibin Chu
Porous materials feature high specific surface areas, enhanced mass transfer efficiency, and altered material–guest interactions, significantly impacting their functionality. Pore engineering is a key strategy for developing materials with tailored pore structures and environments. Porous organic cages (POCs) represent a crucial class of these materials, enabling precise integration of building blocks (BBs) to achieve pre-designed pore characteristics. The diversity of BBs, the modular nature of POCs, selectivity of bond forming chemistry and excellent solution processability are helpful for tuning pore structures and offer customized pore environments for specific applications. Herein, we focus on the pore engineering methodology in POCs and summarize the roles of pore engineering in numerous applications, including gas storage and separation, sensing and detection, energy storage and conversion, membrane separation and heterogeneous catalysis.
{"title":"Tailoring functionalities: pore engineering strategies in porous organic cages for diverse applications","authors":"Mingming Hua, Yang Ding, Chunxiao Lv, Ning Han, Kaibin Chu","doi":"10.1039/d4ta07124g","DOIUrl":"https://doi.org/10.1039/d4ta07124g","url":null,"abstract":"Porous materials feature high specific surface areas, enhanced mass transfer efficiency, and altered material–guest interactions, significantly impacting their functionality. Pore engineering is a key strategy for developing materials with tailored pore structures and environments. Porous organic cages (POCs) represent a crucial class of these materials, enabling precise integration of building blocks (BBs) to achieve pre-designed pore characteristics. The diversity of BBs, the modular nature of POCs, selectivity of bond forming chemistry and excellent solution processability are helpful for tuning pore structures and offer customized pore environments for specific applications. Herein, we focus on the pore engineering methodology in POCs and summarize the roles of pore engineering in numerous applications, including gas storage and separation, sensing and detection, energy storage and conversion, membrane separation and heterogeneous catalysis.","PeriodicalId":82,"journal":{"name":"Journal of Materials Chemistry A","volume":"9 1","pages":""},"PeriodicalIF":11.9,"publicationDate":"2024-12-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142797309","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"材料科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}