Gang-Ding Wang, Wenjie Shi, Yong-Zhi Li, Weigang Lu, Lei Hou, Dan Li
Separating acetylene (C2H2) from carbon dioxide (CO2) is of great industrial importance for achieving high-purity C2H2 (>99%). However, overcoming the trade-off effect between adsorption capacity and selectivity remains a daunting challenge owing to their similar physicochemical properties. Herein, we present a novel cage-like metal-organic framework termed Cu-TPHC for efficiently purifying C2H2 from C2H2/CO2 mixtures. Cu-TPHC exhibits a high C2H2 uptake (157.5 cm3 g-1), C2H2/CO2 selectivity (4.9), and a relatively low C2H2 adsorption enthalpy (29.6 kJ mol-1) at 298 K. The excellent separation potential was demonstrated by breakthrough experiments for an equimolar C2H2/CO2 mixture under various conditions, with good recyclability and a 99.4 % purity of the recovered C2H2. Grand canonical Monte Carlo simulations reveal that the uncoordinated carboxylate oxygen atoms, coordinated water molecules and free OH- anions provide multiple supramolecular binding sites that preferentially interact with C2H2 over CO2.
{"title":"Enabling High C2H2 Storage and Efficient C2H2/CO2 Separation in a Cage-like MOF with Multiple Supramolecular Binding Sites","authors":"Gang-Ding Wang, Wenjie Shi, Yong-Zhi Li, Weigang Lu, Lei Hou, Dan Li","doi":"10.1039/d4ta06472k","DOIUrl":"https://doi.org/10.1039/d4ta06472k","url":null,"abstract":"Separating acetylene (C2H2) from carbon dioxide (CO2) is of great industrial importance for achieving high-purity C2H2 (>99%). However, overcoming the trade-off effect between adsorption capacity and selectivity remains a daunting challenge owing to their similar physicochemical properties. Herein, we present a novel cage-like metal-organic framework termed Cu-TPHC for efficiently purifying C2H2 from C2H2/CO2 mixtures. Cu-TPHC exhibits a high C2H2 uptake (157.5 cm3 g-1), C2H2/CO2 selectivity (4.9), and a relatively low C2H2 adsorption enthalpy (29.6 kJ mol-1) at 298 K. The excellent separation potential was demonstrated by breakthrough experiments for an equimolar C2H2/CO2 mixture under various conditions, with good recyclability and a 99.4 % purity of the recovered C2H2. Grand canonical Monte Carlo simulations reveal that the uncoordinated carboxylate oxygen atoms, coordinated water molecules and free OH- anions provide multiple supramolecular binding sites that preferentially interact with C2H2 over CO2.","PeriodicalId":82,"journal":{"name":"Journal of Materials Chemistry A","volume":"18 1","pages":""},"PeriodicalIF":11.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673762","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}
Organic electrochemical transistors (OECTs) have emerged as promising platforms for biosensors and bioelectronic devices due to their biocompatibility, low power consumption, and sensitivity in amplifying chemical signals. This review delves into the recent advancements in the field of biosensors and bioelectronics utilizing solid-state OECTs with flexible gel electrolytes. Gel electrolytes, including hydrogels and ionic liquid gels, offer improved mechanical compatibility and stability compared to traditional liquid electrolytes, making them suitable for wearable and implantable biosensing applications. We explore the properties and classifications of gel electrolytes for OECTs, highlighting their self-healing, responsive, temperature-resistant, adhesive, and stretchable characteristics. Moreover, we discuss the application of solid-state OECTs based on gel electrolytes in ion sensing, metabolite detection, and electrophysiological sensing. Despite significant progress, challenges such as manufacturing scalability and the development of responsive OECTs persist. Future directions involve leveraging the multi-responsiveness of hydrogel electrolytes for intelligent sensor designs, integrating solid-state OECTs with energy storage devices for self-powered applications, and advancing wireless communication functionalities for real-time health monitoring. This comprehensive overview provides insights into the potential of solid-state OECTs based on gel electrolytes and outlines future research directions in biosensing and bioelectronics.
{"title":"Solid-State Organic Electrochemical Transistors (OECT) Based on Gel Electrolytes for Biosensors and Bioelectronics","authors":"Dongdong Lu, Hu Chen","doi":"10.1039/d4ta05288a","DOIUrl":"https://doi.org/10.1039/d4ta05288a","url":null,"abstract":"Organic electrochemical transistors (OECTs) have emerged as promising platforms for biosensors and bioelectronic devices due to their biocompatibility, low power consumption, and sensitivity in amplifying chemical signals. This review delves into the recent advancements in the field of biosensors and bioelectronics utilizing solid-state OECTs with flexible gel electrolytes. Gel electrolytes, including hydrogels and ionic liquid gels, offer improved mechanical compatibility and stability compared to traditional liquid electrolytes, making them suitable for wearable and implantable biosensing applications. We explore the properties and classifications of gel electrolytes for OECTs, highlighting their self-healing, responsive, temperature-resistant, adhesive, and stretchable characteristics. Moreover, we discuss the application of solid-state OECTs based on gel electrolytes in ion sensing, metabolite detection, and electrophysiological sensing. Despite significant progress, challenges such as manufacturing scalability and the development of responsive OECTs persist. Future directions involve leveraging the multi-responsiveness of hydrogel electrolytes for intelligent sensor designs, integrating solid-state OECTs with energy storage devices for self-powered applications, and advancing wireless communication functionalities for real-time health monitoring. This comprehensive overview provides insights into the potential of solid-state OECTs based on gel electrolytes and outlines future research directions in biosensing and bioelectronics.","PeriodicalId":82,"journal":{"name":"Journal of Materials Chemistry A","volume":"99 1","pages":""},"PeriodicalIF":11.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673725","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}
Shi-Ming Wang, Kai-Hua Wang, Lu Zhou, Tianyang Lu, Eunkyoung Kim, Zhengbo Han, Jun Liang Lin, Lin Liu, Guodong Li
Room-temperature spin-coatable polyoxometalate based composite is explored for low cost electrochromic capacitive film. Transparent stable K6P2W18O64 -polyvinyl alcohol (P2W18-PVA) solution was developed which suit for rigid and flexible substrates. The electrodeposited HKUST-1 particles were employed to create the pore structure in the film leading facile ion transportation. The excellent EC performance of P2W18 was fully expressed in this thin film with the thickness of 500 nm. The state-of-the-art record of 95% optical contrast and 1600 stable EC cycles are achieved. Electrochromic energy storage device with the capacity of 7.89 mF cm-2 was realized with MnO2 as counter electrode. This strategy for the preparation of highly stable and transparent POMs coating at room temperature is a general and simple solution that is not limited to the preparation of electrochromic films.
{"title":"Room-Temperature Spin-Coatable Polyoxometalate Composites for High-Contrast, Large-Area Electrochromic Capacitive Films","authors":"Shi-Ming Wang, Kai-Hua Wang, Lu Zhou, Tianyang Lu, Eunkyoung Kim, Zhengbo Han, Jun Liang Lin, Lin Liu, Guodong Li","doi":"10.1039/d4ta06915c","DOIUrl":"https://doi.org/10.1039/d4ta06915c","url":null,"abstract":"Room-temperature spin-coatable polyoxometalate based composite is explored for low cost electrochromic capacitive film. Transparent stable K6P2W18O64 -polyvinyl alcohol (P2W18-PVA) solution was developed which suit for rigid and flexible substrates. The electrodeposited HKUST-1 particles were employed to create the pore structure in the film leading facile ion transportation. The excellent EC performance of P2W18 was fully expressed in this thin film with the thickness of 500 nm. The state-of-the-art record of 95% optical contrast and 1600 stable EC cycles are achieved. Electrochromic energy storage device with the capacity of 7.89 mF cm-2 was realized with MnO2 as counter electrode. This strategy for the preparation of highly stable and transparent POMs coating at room temperature is a general and simple solution that is not limited to the preparation of electrochromic films.","PeriodicalId":82,"journal":{"name":"Journal of Materials Chemistry A","volume":"6 1","pages":""},"PeriodicalIF":11.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673726","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 rice, as an important strategic material, is stored in the granary every year. Typically, the rice nearly fills the entire granary, making it difficult to detect smoldering in time. Once the smoldering of rice begins, it will be difficult to extinguish. To prevent granary fires, this paper analyzes the pyrolysis products of rice and proposes a novel granary smoldering early warning method based on the color reaction between furfural (the main product during rice smoldering) and aniline hydrochloride, and the excellent gas adsorption performance of three-dimensional covalent organic frameworks (COFs). A small-scale smoldering model of rice storage granary is built. The smoldering of rice in small-scale granary is detected successfully by the designed rice smoldering sensor (RSS). RSS shows good flexibility and ultra-sensitivity for rice smoldering. The minimum monitoring concentration of furfural produced during rice smoldering is 0.03 ug/mL. The early warning mechanism of RSS has also been revealed. This work provides a new method for early warning of grain fires.
{"title":"Ultra-Sensitive Covalent Organic Frameworks based Smoldering Sensor for Early Warning of Granary Fire","authors":"Yunlu Luan, Jing Zhan, Xiaojuan Ye, Xiaowei Mu","doi":"10.1039/d4ta06517d","DOIUrl":"https://doi.org/10.1039/d4ta06517d","url":null,"abstract":"The rice, as an important strategic material, is stored in the granary every year. Typically, the rice nearly fills the entire granary, making it difficult to detect smoldering in time. Once the smoldering of rice begins, it will be difficult to extinguish. To prevent granary fires, this paper analyzes the pyrolysis products of rice and proposes a novel granary smoldering early warning method based on the color reaction between furfural (the main product during rice smoldering) and aniline hydrochloride, and the excellent gas adsorption performance of three-dimensional covalent organic frameworks (COFs). A small-scale smoldering model of rice storage granary is built. The smoldering of rice in small-scale granary is detected successfully by the designed rice smoldering sensor (RSS). RSS shows good flexibility and ultra-sensitivity for rice smoldering. The minimum monitoring concentration of furfural produced during rice smoldering is 0.03 ug/mL. The early warning mechanism of RSS has also been revealed. This work provides a new method for early warning of grain fires.","PeriodicalId":82,"journal":{"name":"Journal of Materials Chemistry A","volume":"14 1","pages":""},"PeriodicalIF":11.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142678460","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}
Liquid metals have garnered significant attention from researchers in recent years, which possess fascinating characteristics originating from their simultaneous metallic and liquid qualities. The great fluidity and conductivity make liquid metals promising for broad prospects in many fields, such as composites, aerospace, flexible electronics, biomedical devices. However, the study of liquid metals still not forming integrated research system nowadays, neglected by the wider research community. The question of “how to improve the basic performance of flexible electronic products and endow them with more unique functions” has emerged. In this review, we provide an overview of the processing methods for liquid metal based flexible devices, with a particular emphasis on various applications based on the conductivity, such as wearable sensors, controllable switches, flexible circuits, devices based on magnetic effect, joule heater, electromagnetic shielding devices. This work comprehensively introduces the application directions of liquid metals in conductivity and aims to offer innovation insights and inspiration for future research endeavors in liquid metal based flexible devices and systems.
{"title":"Recent Advances and Future Prospectives of Flexible and Wearable Applications Based on Liquid Metals Demands","authors":"Yifei Li, Sunwu Xu, Pengyu Zhu, Shuai Zhang, Yuntao Sun, Shuye Zhang, Peng He","doi":"10.1039/d4ta06879c","DOIUrl":"https://doi.org/10.1039/d4ta06879c","url":null,"abstract":"Liquid metals have garnered significant attention from researchers in recent years, which possess fascinating characteristics originating from their simultaneous metallic and liquid qualities. The great fluidity and conductivity make liquid metals promising for broad prospects in many fields, such as composites, aerospace, flexible electronics, biomedical devices. However, the study of liquid metals still not forming integrated research system nowadays, neglected by the wider research community. The question of “how to improve the basic performance of flexible electronic products and endow them with more unique functions” has emerged. In this review, we provide an overview of the processing methods for liquid metal based flexible devices, with a particular emphasis on various applications based on the conductivity, such as wearable sensors, controllable switches, flexible circuits, devices based on magnetic effect, joule heater, electromagnetic shielding devices. This work comprehensively introduces the application directions of liquid metals in conductivity and aims to offer innovation insights and inspiration for future research endeavors in liquid metal based flexible devices and systems.","PeriodicalId":82,"journal":{"name":"Journal of Materials Chemistry A","volume":"10 1","pages":""},"PeriodicalIF":11.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673734","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}
Ahmed N Mahfouz, Andrew Z Haddad, Jordan D Kocher, Akanksha K Menon
Thermally responsive ionic liquids (ILs) exhibit liquid-liquid phase separation when mixed with water and heated above a lower critical solution temperature (LCST), resulting in a water-rich (WR) and an IL-rich (ILR) phase. These binary IL-water mixtures can be employed in a variety of thermodynamic processes such as forward osmosis (FO) desalination, for which two solution properties are desirable: low phase separation temperature and high osmotic strength (osmolality). However, these two properties are interlinked, with ILs that exhibit higher osmotic strengths typically requiring higher phase separation temperatures. This behavior tends to arise from the hydrophilicity of the IL cations, which enhances osmotic strength while also elevating the phase separation temperature. In this work, we highlight a pathway to overcome this tradeoff by developing ternary IL mixtures (two ILs with varying cation hydrophilicity mixed with water), which lowers the phase separation temperature while maintaining and even enhancing the osmotic strength of the solution. We characterize the mixing behavior (osmolality, phase separation temperature, WR phase purity, and WR to ILR phase mass ratio) of four ILs as a function of their concentration in solution. We find that an enhancement of up to 81.6% in the osmolality with a concomitant reduction of up to 15.4% in the phase separation temperature can be achieved using this approach. The ternary mixture is also shown to improve the phase separation kinetics by nearly 95% compared to the binary mixture. Overall, this work highlights a new pathway to improve the performance of LCST ILs for water and energy applications.
热响应离子液体（ILs）与水混合并加热至较低的临界溶液温度（LCST）以上时，会出现液-液相分离，形成富水相（WR）和富离子液体相（ILR）。这些二元 IL 水混合物可用于各种热力学过程，例如正向渗透（FO）脱盐，其中有两种溶液特性是理想的：低相分离温度和高渗透强度（渗透压）。然而，这两种特性是相互关联的，渗透强度较高的 IL 通常需要较高的相分离温度。这种行为往往源于 IL 阳离子的亲水性，它在提高渗透强度的同时也提高了相分离温度。在这项工作中，我们强调了一种克服这种折衷的途径，即开发三元 IL 混合物（两种具有不同阳离子亲水性的 IL 与水混合），从而降低相分离温度，同时保持甚至增强溶液的渗透强度。我们将四种 IL 的混合行为（渗透压、相分离温度、WR 相纯度以及 WR 与 ILR 相质量比）表征为它们在溶液中浓度的函数。我们发现，使用这种方法可以提高渗透压达 81.6%，同时降低相分离温度达 15.4%。与二元混合物相比，三元混合物还能将相分离动力学提高近 95%。总之，这项研究成果为提高 LCST IL 在水和能源应用领域的性能开辟了一条新途径。
{"title":"Performance enhancement of aqueous ionic liquids with lower critical solution temperature (LCST) behavior through ternary mixtures","authors":"Ahmed N Mahfouz, Andrew Z Haddad, Jordan D Kocher, Akanksha K Menon","doi":"10.1039/d4ta07575g","DOIUrl":"https://doi.org/10.1039/d4ta07575g","url":null,"abstract":"Thermally responsive ionic liquids (ILs) exhibit liquid-liquid phase separation when mixed with water and heated above a lower critical solution temperature (LCST), resulting in a water-rich (WR) and an IL-rich (ILR) phase. These binary IL-water mixtures can be employed in a variety of thermodynamic processes such as forward osmosis (FO) desalination, for which two solution properties are desirable: low phase separation temperature and high osmotic strength (osmolality). However, these two properties are interlinked, with ILs that exhibit higher osmotic strengths typically requiring higher phase separation temperatures. This behavior tends to arise from the hydrophilicity of the IL cations, which enhances osmotic strength while also elevating the phase separation temperature. In this work, we highlight a pathway to overcome this tradeoff by developing ternary IL mixtures (two ILs with varying cation hydrophilicity mixed with water), which lowers the phase separation temperature while maintaining and even enhancing the osmotic strength of the solution. We characterize the mixing behavior (osmolality, phase separation temperature, WR phase purity, and WR to ILR phase mass ratio) of four ILs as a function of their concentration in solution. We find that an enhancement of up to 81.6% in the osmolality with a concomitant reduction of up to 15.4% in the phase separation temperature can be achieved using this approach. The ternary mixture is also shown to improve the phase separation kinetics by nearly 95% compared to the binary mixture. Overall, this work highlights a new pathway to improve the performance of LCST ILs for water and energy applications.","PeriodicalId":82,"journal":{"name":"Journal of Materials Chemistry A","volume":"15 1","pages":""},"PeriodicalIF":11.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673763","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}
MAX phases are emerging as efficient electromagnetic wave absorption (EMA) materials, favored for their outstanding conductivity, high-temperature stability, and corrosion resistance. However, the limitations of a singular energy loss mechanism and the need for a high filler ratio hinder their further development. Herein, a template method utilizing absorbent cotton as a carbon source was employed to synthesize 0D/1D Cr2GaC/C hybrid materials. The bottom-up preparation strategy maintains the size of the Cr2GaC MAX-phase particles at ~200 nm while ensuring their uniform distribution within the carbon fibers. The abundant heterointerfaces between Cr2GaC and carbon enhanced interfacial polarization, while the carbon fiber network improved conduction loss. Consequently, the Cr2GaC/C hybrid exhibits excellent EMA properties, achieving a minimum reflection loss value of -59.0 dB at a thickness of only 1.56 mm and an ultra-low filler content of 15 wt.%. Additionally, its maximum radar cross section reduction value is 17.78 dB m², showing excellent stealth capability. This research provides new insights into the nanoscale synthesis of MAX phases and offers promising pathways for optimizing their EMA performance.
MAX 相作为一种高效的电磁波吸收（EMA）材料，因其出色的导电性、高温稳定性和耐腐蚀性而备受青睐。然而，单一的能量损失机制和对高填料比的要求阻碍了它们的进一步发展。本文采用模板法，利用吸水棉作为碳源合成了 0D/1D Cr2GaC/C 混合材料。自下而上的制备策略将 Cr2GaC MAX 相颗粒的尺寸保持在约 200 nm，同时确保了它们在碳纤维中的均匀分布。Cr2GaC 与碳之间丰富的异质界面增强了界面极化，而碳纤维网络则改善了传导损耗。因此，Cr2GaC/C 混合物具有出色的 EMA 特性，在厚度仅为 1.56 毫米、填充物含量为 15 wt.% 的超低条件下，最小反射损耗值达到 -59.0 dB。此外，它的最大雷达截面降低值为 17.78 dB m²，显示出卓越的隐身能力。这项研究为 MAX 相的纳米级合成提供了新的见解，并为优化其 EMA 性能提供了前景广阔的途径。
{"title":"Heterointerface engineering in Cr2GaC/C hybrids through bottom-up template synthesis for enhanced electromagnetic wave absorption","authors":"Feiyue Hu, Shengyu Xie, Fushuo Wu, Jian Liu, Peigen Zhang, Jianxiang Ding, Bingbing Fan, Wei Zheng, Longzhu Cai, Zhengming Sun","doi":"10.1039/d4ta07294d","DOIUrl":"https://doi.org/10.1039/d4ta07294d","url":null,"abstract":"MAX phases are emerging as efficient electromagnetic wave absorption (EMA) materials, favored for their outstanding conductivity, high-temperature stability, and corrosion resistance. However, the limitations of a singular energy loss mechanism and the need for a high filler ratio hinder their further development. Herein, a template method utilizing absorbent cotton as a carbon source was employed to synthesize 0D/1D Cr2GaC/C hybrid materials. The bottom-up preparation strategy maintains the size of the Cr2GaC MAX-phase particles at ~200 nm while ensuring their uniform distribution within the carbon fibers. The abundant heterointerfaces between Cr2GaC and carbon enhanced interfacial polarization, while the carbon fiber network improved conduction loss. Consequently, the Cr2GaC/C hybrid exhibits excellent EMA properties, achieving a minimum reflection loss value of -59.0 dB at a thickness of only 1.56 mm and an ultra-low filler content of 15 wt.%. Additionally, its maximum radar cross section reduction value is 17.78 dB m², showing excellent stealth capability. This research provides new insights into the nanoscale synthesis of MAX phases and offers promising pathways for optimizing their EMA performance.","PeriodicalId":82,"journal":{"name":"Journal of Materials Chemistry A","volume":"63 1","pages":""},"PeriodicalIF":11.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673786","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}
Jie Wu, Anqi Huang, Wen Cao, Xuehui Gao, Zhongwei Chen
Alkaline oxygen evolution reaction (OER), involving a four-electron transfer process, is characterized by high overpotential and extremely sluggish reaction kinetics, posing a significant challenge for catalyst design. Herein, a strategy is proposed to modulate the electronic structure of electrocatalyst by constructing cobalt-doped Ni3S2@NiFe-LDH (Co-Ni3S2@NiFe-LDH) hierarchical hollow heterojunction with enhanced local electric fields (ELEF). The ELEF in the heterojunction induces band bending of the components, expediting electron transfer and accelerating OER kinetics. Furthermore, the hierarchical hollow structure offers a large specific surface area that ensures full exposure of adsorption and active sites. Benefiting from these synergetic advantages, Co-Ni3S2@NiFe-LDH shows remarkable performance and stability with low overpotential of only 217 mV at 50 mA cm-2. Density functional theory (DFT) calculations further confirms that the ELEF can optimize the adsorption energy of intermediate reaction species, reduce reaction energy barriers, and modulate the d-band center of active sites, thereby improving the inherent catalyst activity.
碱性氧进化反应（OER）涉及四电子转移过程，具有过电位高、反应动力学极其缓慢的特点，给催化剂设计带来了巨大挑战。本文提出了一种通过构建掺钴的 Ni3S2@NiFe-LDH（Co-Ni3S2@NiFe-LDH）分层空心异质结来调节电催化剂电子结构的策略，该异质结具有增强的局部电场（ELEF）。异质结中的 ELEF 会引起各成分的带弯曲，从而加快电子转移并加速 OER 动力学。此外，分层中空结构提供了较大的比表面积，确保了吸附和活性位点的充分暴露。得益于这些协同优势，Co-Ni3S2@NiFe-LDH 表现出卓越的性能和稳定性，在 50 mA cm-2 时过电位仅为 217 mV。密度泛函理论（DFT）计算进一步证实，ELEF 可以优化中间反应物的吸附能，降低反应能垒，调节活性位点的 d 带中心，从而提高催化剂的固有活性。
{"title":"Construction of Cobalt-doped Ni3S2@NiFe-LDH Heterojunction with Enhanced Local Electric Field for Efficient Oxygen Evolution Reaction","authors":"Jie Wu, Anqi Huang, Wen Cao, Xuehui Gao, Zhongwei Chen","doi":"10.1039/d4ta06830k","DOIUrl":"https://doi.org/10.1039/d4ta06830k","url":null,"abstract":"Alkaline oxygen evolution reaction (OER), involving a four-electron transfer process, is characterized by high overpotential and extremely sluggish reaction kinetics, posing a significant challenge for catalyst design. Herein, a strategy is proposed to modulate the electronic structure of electrocatalyst by constructing cobalt-doped Ni3S2@NiFe-LDH (Co-Ni3S2@NiFe-LDH) hierarchical hollow heterojunction with enhanced local electric fields (ELEF). The ELEF in the heterojunction induces band bending of the components, expediting electron transfer and accelerating OER kinetics. Furthermore, the hierarchical hollow structure offers a large specific surface area that ensures full exposure of adsorption and active sites. Benefiting from these synergetic advantages, Co-Ni3S2@NiFe-LDH shows remarkable performance and stability with low overpotential of only 217 mV at 50 mA cm-2. Density functional theory (DFT) calculations further confirms that the ELEF can optimize the adsorption energy of intermediate reaction species, reduce reaction energy barriers, and modulate the d-band center of active sites, thereby improving the inherent catalyst activity.","PeriodicalId":82,"journal":{"name":"Journal of Materials Chemistry A","volume":"197 1","pages":""},"PeriodicalIF":11.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673723","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}
Carbon dioxide electroreduction reaction (CO2RR) has emerged as a viable strategy to address pressing energy and environmental challenges. Single-atom catalysts (SACs) are of particular interest for CO2RR due to their maximized atom utilization. The incorporation of heteroatoms as ligands is a common strategy to modify the geometric and electronic structures of metal centers to enhance performance. Here, we employed density functional theory study to investigate nitrogen-coordinated SACs with various heteroatom ligands, and elucidated the structural rule of SACs on CO2RR. The results show that the planar structural SACs exhibit relatively better stabilities than the raised ones, and their stabilities exhibit a volcano-shaped trend as a function of the ligand radius, with both excessively large and small radius compromising stability. Although the raised structural SACs have the better ability to activate CO2 for the tip effect, they also hinder the CO desorption and facilitate the H+ adsorption, leading to relatively poor CO2RR activity and selectivity (vs HER). In contrast, the planar-structured SACs generally show better activity and CO2RR selectivity, where promoting the CO2 activation/hydrogenation step is necessary. This work provides fundamental insights into the structure-dependence of SACs, and offers guidance for designing SACs for CO2RR or other reactions.
{"title":"Structural Rule of Heteroatom-Modified Single-Atom Catalysts for CO2 Electroreduction Reaction","authors":"Xinyuan Sui, Haiyang Yuan, Yu Hou","doi":"10.1039/d4ta06604a","DOIUrl":"https://doi.org/10.1039/d4ta06604a","url":null,"abstract":"Carbon dioxide electroreduction reaction (CO2RR) has emerged as a viable strategy to address pressing energy and environmental challenges. Single-atom catalysts (SACs) are of particular interest for CO2RR due to their maximized atom utilization. The incorporation of heteroatoms as ligands is a common strategy to modify the geometric and electronic structures of metal centers to enhance performance. Here, we employed density functional theory study to investigate nitrogen-coordinated SACs with various heteroatom ligands, and elucidated the structural rule of SACs on CO2RR. The results show that the planar structural SACs exhibit relatively better stabilities than the raised ones, and their stabilities exhibit a volcano-shaped trend as a function of the ligand radius, with both excessively large and small radius compromising stability. Although the raised structural SACs have the better ability to activate CO2 for the tip effect, they also hinder the CO desorption and facilitate the H+ adsorption, leading to relatively poor CO2RR activity and selectivity (vs HER). In contrast, the planar-structured SACs generally show better activity and CO2RR selectivity, where promoting the CO2 activation/hydrogenation step is necessary. This work provides fundamental insights into the structure-dependence of SACs, and offers guidance for designing SACs for CO2RR or other reactions.","PeriodicalId":82,"journal":{"name":"Journal of Materials Chemistry A","volume":"14 1","pages":""},"PeriodicalIF":11.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673724","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}
Dong Han Ha, Gichang Noh, Hakseong Kim, Dong Hwan Kim, Jeongho Kim, Suyong Jung, Chanyong Hwang, Ha Young Lee, Yong Ju Yun, Joon Young Kwak, Kibum Kang, Sam Nyung Yi
Raman studies of manganese dioxide (MnO2), a crucial material for sustainable and innovative solutions in energy storage and environmental remediation, have predominantly been conducted on fine-grained aggregates, leaving the identification of Raman peaks open to debate. To address this, in this study the Raman spectra of potassium (K)-birnessite single crystals with varying crystal thickness, temperature, and polarization configuration are measured. An acoustic phonon mode of birnessite is identified, which is found to be sensitive to both crystal thickness and interlayer spacing, with its frequency increasing by approximately 35% when the c-axis lattice parameter is reduced from 0.70 to 0.65 nm by the removal of interlayer water. In contrast, the dependence of the optical phonon modes on crystal thickness and interlayer spacing is not particularly noticeable. It is demonstrated that the characteristic Raman peak of K-birnessite, observed at approximately 559 cm–1, originates from a two-dimensional hexagonal configuration of cations and water molecules within the interlayer space, rather than from the MnO6 octahedra. Additionally, the doubly degenerate vibrational mode of MnO6 octahedra, corresponding to the motion of oxygen atoms in the basal plane, splits into two, confirming that the MnO6 octahedra are distorted by the Jahn–Teller effect.
{"title":"Raman spectroscopy study of K-birnessite single crystals","authors":"Dong Han Ha, Gichang Noh, Hakseong Kim, Dong Hwan Kim, Jeongho Kim, Suyong Jung, Chanyong Hwang, Ha Young Lee, Yong Ju Yun, Joon Young Kwak, Kibum Kang, Sam Nyung Yi","doi":"10.1039/d4ta06118g","DOIUrl":"https://doi.org/10.1039/d4ta06118g","url":null,"abstract":"Raman studies of manganese dioxide (MnO<small><sub>2</sub></small>), a crucial material for sustainable and innovative solutions in energy storage and environmental remediation, have predominantly been conducted on fine-grained aggregates, leaving the identification of Raman peaks open to debate. To address this, in this study the Raman spectra of potassium (K)-birnessite single crystals with varying crystal thickness, temperature, and polarization configuration are measured. An acoustic phonon mode of birnessite is identified, which is found to be sensitive to both crystal thickness and interlayer spacing, with its frequency increasing by approximately 35% when the c-axis lattice parameter is reduced from 0.70 to 0.65 nm by the removal of interlayer water. In contrast, the dependence of the optical phonon modes on crystal thickness and interlayer spacing is not particularly noticeable. It is demonstrated that the characteristic Raman peak of K-birnessite, observed at approximately 559 cm<small><sup>–1</sup></small>, originates from a two-dimensional hexagonal configuration of cations and water molecules within the interlayer space, rather than from the MnO<small><sub>6</sub></small> octahedra. Additionally, the doubly degenerate vibrational mode of MnO<small><sub>6</sub></small> octahedra, corresponding to the motion of oxygen atoms in the basal plane, splits into two, confirming that the MnO6 octahedra are distorted by the Jahn–Teller effect.","PeriodicalId":82,"journal":{"name":"Journal of Materials Chemistry A","volume":"57 1","pages":""},"PeriodicalIF":11.9,"publicationDate":"2024-11-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142673755","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}
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