Accounts of materials research最新文献

{"title":"Tailoring Stepped Layered Titanates for Sodium-Ion Battery Applications","authors":"Wei Yin,&nbsp;Juhyeon Ahn,&nbsp;Gözde Barim,&nbsp;Judith Alvarado and Marca M. Doeff*,&nbsp;","doi":"10.1021/accountsmr.4c0008010.1021/accountsmr.4c00080","DOIUrl":"https://doi.org/10.1021/accountsmr.4c00080https://doi.org/10.1021/accountsmr.4c00080","url":null,"abstract":"<p >Concerns about sustainability and supply chain issues associated with lithium-ion batteries (LIBs) have led researchers and companies around the world to investigate alternative technologies. Of all the so-called “beyond LIBs”, sodium-ion batteries (NIBs) are in the most advanced stage of development, and are being considered for grid storage applications as well as moderate-range electric vehicles. While graphite is the most commonly used anode material for LIBs, hard carbons are used in NIBs because sodium insertion into graphite does not occur to a useful extent. Other possibilities, based on cost and availability arguments, are titanates, which are generally denser than disordered carbons, meaning more material can be packed into a given volume, leading potentially to greater energy density. We have researched stepped layered titanates for use as anode materials, focusing on two types of structures. The first is “sodium nonatitanate” or NNT, with the composition NaTi₃O₆(OH)·2H₂O having six Ti⁴⁺O₆ octahedra joined together in steps to form layers with sodium ions and water in-between. The lepidocrocite-type titanate structure, contains zigzag layers (or steps one Ti⁴⁺O₆ unit across). These exist in a wide range of compositions, and contain large exchangeable cations between the layers. An unusual feature of both NNT and the lepidocrocite titanates is the very low potentials (0.3–0.5 V vs Na⁺/Na) at which they insert sodium. This makes them particularly attractive for anode applications. Another interesting feature is the ability to tailor the electrochemical properties by various modifications, such as heat-treatment to remove water and change the structure, introduction of vacancies, ion-exchange, surface modifications, and carbon coating or graphene wrapping, all of which alter the electrochemical properties. Finally, heterostructuring (interleaving titanate layers with carbon) results in new materials with different redox properties. For all the titanates, the first cycle Coulombic efficiency (C.E.) is very sensitive to the binder used in the electrode fabrication and the electrolyte used. Because sodium insertion occurs at such a low potential, some electrolyte and binder are irreversibly reduced during the first cycle to form a protective solid electrolyte interphase (SEI). In a full cell, it is important to maximize the C.E. because all the cyclable sodium must come from the cathode, so cells must be overbuilt to compensate for these losses. Proper selection of binder and electrolyte results in improved cycling performance and minimal first cycle losses. Finally, examples of full cells containing some of the materials under discussion are provided.</p>","PeriodicalId":72040,"journal":{"name":"Accounts of materials research","volume":"5 8","pages":"933–943 933–943"},"PeriodicalIF":14.0,"publicationDate":"2024-07-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142039430","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unique Optical Properties of Cellulosic Materials","authors":"Jade Poisson, Kai Zhang","doi":"10.1021/accountsmr.4c00013","DOIUrl":"https://doi.org/10.1021/accountsmr.4c00013","url":null,"abstract":"Our natural environment inspires much of our innovation in all fields of research and application. In particular, unique optical properties are observed in natural systems such as bioluminescence and structural colors generated by bioengineering specific nanostructures. Cellulose is one such naturally occurring material that has been particularly surprising and impactful. Cellulose is one of the most abundant biopolymers with incredible versatility and distinct optical properties. Cellulose nanomaterials can readily self-assemble into chiral nematic phases which induces birefringence resulting in unique optical properties as well as causing incident irradiation to be circularly polarized. These properties unlock possibilities for cellulose materials to be used in encryption and sensing applications to name a few. Thus, cellulose materials have been used extensively as chiral scaffolds in composites but not as luminophores themselves in circularly polarized luminescent (CPL) materials. Recent discovery of the intrinsic luminescence of cellulose has expanded the use of cellulose materials in optical applications.","PeriodicalId":72040,"journal":{"name":"Accounts of materials research","volume":"125 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141561794","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unique Optical Properties of Cellulosic Materials","authors":"Jade Poisson,&nbsp; and ,&nbsp;Kai Zhang*,&nbsp;","doi":"10.1021/accountsmr.4c0001310.1021/accountsmr.4c00013","DOIUrl":"https://doi.org/10.1021/accountsmr.4c00013https://doi.org/10.1021/accountsmr.4c00013","url":null,"abstract":"&lt;p &gt;Our natural environment inspires much of our innovation in all fields of research and application. In particular, unique optical properties are observed in natural systems such as bioluminescence and structural colors generated by bioengineering specific nanostructures. Cellulose is one such naturally occurring material that has been particularly surprising and impactful. Cellulose is one of the most abundant biopolymers with incredible versatility and distinct optical properties. Cellulose nanomaterials can readily self-assemble into chiral nematic phases which induces birefringence resulting in unique optical properties as well as causing incident irradiation to be circularly polarized. These properties unlock possibilities for cellulose materials to be used in encryption and sensing applications to name a few. Thus, cellulose materials have been used extensively as chiral scaffolds in composites but not as luminophores themselves in circularly polarized luminescent (CPL) materials. Recent discovery of the intrinsic luminescence of cellulose has expanded the use of cellulose materials in optical applications.&lt;/p&gt;&lt;p &gt;In addition to structural colors, the study of luminescent properties of cellulose is a perfect example of the scientific method. For many years it was presumed that such materials would only emit if they were contaminated with other luminophores. Researchers stress tested this hypothesis and found that not just cellulose but many everyday, biological and even very structurally simple molecules emit UV and visible light via a clustering triggered emission (CTE) mechanism. This phenomenon employs through-space conjugation of heteroatoms wherein the electron clouds of nearby electron moieties can overlap. CTE combines aspects of aggregation-induced emission (AIE) and crystallization-induced phosphorescence (CIP). There are several characteristic features observed in materials demonstrating CTE. These include concentration-dependent emission, excitation wavelength-dependent and multicolor emission, and room temperature phosphorescence.&lt;/p&gt;&lt;p &gt;The optical properties of cellulose are found to be particularly sensitive to environmental stimuli such as pH, humidity, temperature, etc. thus making them ideal for luminescent sensing applications. Cellulose-derived materials have also been used in a broad spectrum of other applications including encryption, bioimaging, and analytical tools. However, there are several aspects of the field that have yet to be explored. Arguably, the most important of these is the lack of specificity in the CTE mechanism. It is currently unknown what the specific requirements for cluster sizes are and what the maximum spacer length is in order for the cellulose materials to still enable effective heteroatom electronic overlap. Additionally, the materials can often suffer from low quantum yields.&lt;/p&gt;&lt;p &gt;This account includes a brief overview of some of the most impactful optical properties of cellulose materia","PeriodicalId":72040,"journal":{"name":"Accounts of materials research","volume":"5 8","pages":"920–932 920–932"},"PeriodicalIF":14.0,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142039370","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Polymer-Based Fabrication of 2D Metallic and Ceramic Nanomaterials","authors":"Yiyu Yao, Wenqing Zhu, Yun Teng, Chuanzheng Li, Yong Yang","doi":"10.1021/accountsmr.4c00122","DOIUrl":"https://doi.org/10.1021/accountsmr.4c00122","url":null,"abstract":"Since the ground-breaking achievement of successfully exfoliating single-layer graphene in 2004, there has been significant and rapid development in the field of two-dimensional (2D) nanomaterials. In the field of materials science, 2D nanomaterials are defined as freestanding nanomembranes with a thickness below 100 nm and other lateral dimensions that can extend to the millimeter scale or beyond. These materials exhibit exceptional mechanical, physical, and chemical properties due to their extremely high surface area to volume ratios, surpassing those of their bulk counterparts. As a result, numerous top-down and bottom-up methods have emerged over the past decades to synthesize novel 2D nanomaterials, catering to diverse applications. In this Account, we review the existing top-down methods, such as mechanical compression and mechanical exfoliation, as well as bottom-up methods including hydrothermal induction/solvothermal synthesis, chemical vapor deposition synthesis, etc. We critically discuss the advantages and limitations of each method. Subsequently, we highlight our recently developed method known as polymer surface buckling enabled exfoliation (PSBEE). Unlike previous synthesis techniques, PSBEE is based on the chemical reaction between metals and polymers to fabricate 2D nanomaterials with unique nanostructures. This approach offers a simple, efficient, cost-effective, and environmentally friendly means of achieving large-scale production of 2D nanomaterials, featuring an extremely high lateral size to thickness ratio ranging from 10&lt;sup&gt;6&lt;/sup&gt; to 10&lt;sup&gt;7&lt;/sup&gt;. Notably, PSBEE eliminates the need for chemical etching and enables precise control over the morphology of the synthesized nanomaterials, allowing for transitions from 2D nanomembranes to 1D nanotubes. Through thermal annealing, some of the PSBEE-fabricated 2D nanomaterials, such as 2D gold nanomaterials, can undergo pyrolysis and transform into 0D gold nanoparticles. Furthermore, the versatility of PSBEE extends beyond 2D metallic nanomaterials to the synthesis of 2D ceramic nanomaterials, showcasing its broad applicability across diverse material systems. The unique nanostructures of PSBEE-fabricated 2D nanomaterials, usually featuring a network of nanosized ceramics and metals, contribute to their exceptional mechanical and functional properties. These include an outstanding elastic strain limit, superb strength, remarkable plasticity, superior fracture toughness, high electrocatalytic properties, and unique triboelectric performance. Consequently, these properties lead to novel applications of the PSBEE-fabricated nanomaterials, such as triboelectric sensing and 2D electrocatalysis. At the same time, the PSBEE method also offers notable advantages in terms of scalable production, high throughput efficiency, and low energy consumption, making it highly suitable for future industrial applications. In general, polymer-based fabrication of 2D nanomaterials opens up possibili","PeriodicalId":72040,"journal":{"name":"Accounts of materials research","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141561805","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Polymer-Based Fabrication of 2D Metallic and Ceramic Nanomaterials","authors":"Yiyu Yao,&nbsp;Wenqing Zhu,&nbsp;Yun Teng,&nbsp;Chuanzheng Li and Yong Yang*,&nbsp;","doi":"10.1021/accountsmr.4c0012210.1021/accountsmr.4c00122","DOIUrl":"https://doi.org/10.1021/accountsmr.4c00122https://doi.org/10.1021/accountsmr.4c00122","url":null,"abstract":"&lt;p &gt;Since the ground-breaking achievement of successfully exfoliating single-layer graphene in 2004, there has been significant and rapid development in the field of two-dimensional (2D) nanomaterials. In the field of materials science, 2D nanomaterials are defined as freestanding nanomembranes with a thickness below 100 nm and other lateral dimensions that can extend to the millimeter scale or beyond. These materials exhibit exceptional mechanical, physical, and chemical properties due to their extremely high surface area to volume ratios, surpassing those of their bulk counterparts. As a result, numerous top-down and bottom-up methods have emerged over the past decades to synthesize novel 2D nanomaterials, catering to diverse applications. In this Account, we review the existing top-down methods, such as mechanical compression and mechanical exfoliation, as well as bottom-up methods including hydrothermal induction/solvothermal synthesis, chemical vapor deposition synthesis, etc. We critically discuss the advantages and limitations of each method. Subsequently, we highlight our recently developed method known as polymer surface buckling enabled exfoliation (PSBEE). Unlike previous synthesis techniques, PSBEE is based on the chemical reaction between metals and polymers to fabricate 2D nanomaterials with unique nanostructures. This approach offers a simple, efficient, cost-effective, and environmentally friendly means of achieving large-scale production of 2D nanomaterials, featuring an extremely high lateral size to thickness ratio ranging from 10&lt;sup&gt;6&lt;/sup&gt; to 10&lt;sup&gt;7&lt;/sup&gt;. Notably, PSBEE eliminates the need for chemical etching and enables precise control over the morphology of the synthesized nanomaterials, allowing for transitions from 2D nanomembranes to 1D nanotubes. Through thermal annealing, some of the PSBEE-fabricated 2D nanomaterials, such as 2D gold nanomaterials, can undergo pyrolysis and transform into 0D gold nanoparticles. Furthermore, the versatility of PSBEE extends beyond 2D metallic nanomaterials to the synthesis of 2D ceramic nanomaterials, showcasing its broad applicability across diverse material systems. The unique nanostructures of PSBEE-fabricated 2D nanomaterials, usually featuring a network of nanosized ceramics and metals, contribute to their exceptional mechanical and functional properties. These include an outstanding elastic strain limit, superb strength, remarkable plasticity, superior fracture toughness, high electrocatalytic properties, and unique triboelectric performance. Consequently, these properties lead to novel applications of the PSBEE-fabricated nanomaterials, such as triboelectric sensing and 2D electrocatalysis. At the same time, the PSBEE method also offers notable advantages in terms of scalable production, high throughput efficiency, and low energy consumption, making it highly suitable for future industrial applications. In general, polymer-based fabrication of 2D nanomaterials opens up possi","PeriodicalId":72040,"journal":{"name":"Accounts of materials research","volume":"5 8","pages":"944–957 944–957"},"PeriodicalIF":14.0,"publicationDate":"2024-07-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142039369","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Organic Mixed Conductors in Electrochemical Transistors for Bioelectronic Applications","authors":"Jiajun Song, Li Li, Wai-Yeung Wong, Feng Yan","doi":"10.1021/accountsmr.4c00124","DOIUrl":"https://doi.org/10.1021/accountsmr.4c00124","url":null,"abstract":"Organic semiconductors have emerged as promising materials for facilitating communication between electronic systems and biological entities due to their distinctive advantages, such as structural similarity to biological substances, biocompatibility, tailorability, and mechanical flexibility. Organic bioelectronics mainly focuses on developing devices capable of sensing biological substances and signals, as well as stimulating or regulating biological processes. This interdisciplinary field encompasses various applications, ranging from healthcare monitoring and diagnostics to neuroprosthetics and human–machine interfaces.","PeriodicalId":72040,"journal":{"name":"Accounts of materials research","volume":"27 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141561823","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Organic Mixed Conductors in Electrochemical Transistors for Bioelectronic Applications","authors":"Jiajun Song,&nbsp;Li Li*,&nbsp;Wai-Yeung Wong* and Feng Yan*,&nbsp;","doi":"10.1021/accountsmr.4c0012410.1021/accountsmr.4c00124","DOIUrl":"https://doi.org/10.1021/accountsmr.4c00124https://doi.org/10.1021/accountsmr.4c00124","url":null,"abstract":"&lt;p &gt;Organic semiconductors have emerged as promising materials for facilitating communication between electronic systems and biological entities due to their distinctive advantages, such as structural similarity to biological substances, biocompatibility, tailorability, and mechanical flexibility. Organic bioelectronics mainly focuses on developing devices capable of sensing biological substances and signals, as well as stimulating or regulating biological processes. This interdisciplinary field encompasses various applications, ranging from healthcare monitoring and diagnostics to neuroprosthetics and human–machine interfaces.&lt;/p&gt;&lt;p &gt;Among various organic devices, organic electrochemical transistors (OECTs) have gained significant attention in bioelectronics due to their effective coupling of electronic and ionic transports. OECTs utilize organic mixed ionic–electronic conductors (OMIECs) as ion-permeable channel materials, enabling ion doping throughout the entire channel. This unique volumetric doping gives OECTs ultrahigh transconductance at low working voltages, making them advantageous for highly sensitive biosensing and reliable recording of electrophysiological signals with enhanced signal-to-noise ratios. The properties of OMIECs play a crucial role in determining the device performance and the application scenarios, leading to considerable interest in recent decades.&lt;/p&gt;&lt;p &gt;Understanding the relationship between material figures of merit and specific applications is crucial for guiding material design and selection. This account focuses on the recent advances in OMIECs development for OECTs and highlights their impact on bioelectronic applications. First, we introduce the operation of OECTs, emphasizing the coupling of electronic and ionic circuits and the unique bulk doping mechanism that sets them apart from conventional field-effect transistors. Potential factors influencing transconductance and transient behavior are discussed. Then, we delve into the historical perspective on OMIECs development in OECTs, underscoring material design strategies that enable mixed conduction, including the introduction of glycolated side chains and the utilization of emerging 2D nanoporous structures. Subsequently, we explore the beneficial traits of OMIECs for bioelectronic applications. We discuss the strategies to harness the high transconductance originating from OMIECs for achieving high-performance biosensors and recording electrophysiological signals with superior signal-to-noise ratios. Additionally, we critically examine the latest strategies employed in the realization of stretchable, self-healing, and bioadhesive OMIECs. These innovative features have made significant contributions to wearable and implantable applications. The integration of stretchability ensures compatibility with the dynamic nature of biological entities, enabling robust and reliable performance. The self-healing capabilities of OMIECs exhibit a remarkable ability to aut","PeriodicalId":72040,"journal":{"name":"Accounts of materials research","volume":"5 9","pages":"1036–1047 1036–1047"},"PeriodicalIF":14.0,"publicationDate":"2024-07-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142326316","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Self-Assembly of Multimolecular Components for Engineering Enzyme-Mimetic Materials","authors":"Shichao Xu, Yuanxi Liu, Baoli Zhang, Shan Li, Xiangyu Ye, Zhen-Gang Wang","doi":"10.1021/accountsmr.4c00143","DOIUrl":"https://doi.org/10.1021/accountsmr.4c00143","url":null,"abstract":"Natural enzymes, with their intricate three-dimensional structures, facilitate a wide array of biochemical reactions with exceptional precision and speed. The catalytic capabilities of enzymes arise from the distinctive structures of their active sites, where functional groups collaborate or aid cofactors (organic or ionic) in binding substrates with specificity and catalyzing transformations. Inspired by the structure–function relationship of enzymes, supramolecular self-assembly, a bottom-up approach in nanofabrication, has been employed to create enzyme-mimetic catalysts. However, accurately replicating enzymatic active sites poses a formidable challenge, primarily because of the intricacies in mimicking the complexity of natural protein folding.","PeriodicalId":72040,"journal":{"name":"Accounts of materials research","volume":"21 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141551813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Self-Assembly of Multimolecular Components for Engineering Enzyme-Mimetic Materials","authors":"Shichao Xu,&nbsp;Yuanxi Liu,&nbsp;Baoli Zhang,&nbsp;Shan Li,&nbsp;Xiangyu Ye and Zhen-Gang Wang*,&nbsp;","doi":"10.1021/accountsmr.4c0014310.1021/accountsmr.4c00143","DOIUrl":"https://doi.org/10.1021/accountsmr.4c00143https://doi.org/10.1021/accountsmr.4c00143","url":null,"abstract":"&lt;p &gt;Natural enzymes, with their intricate three-dimensional structures, facilitate a wide array of biochemical reactions with exceptional precision and speed. The catalytic capabilities of enzymes arise from the distinctive structures of their active sites, where functional groups collaborate or aid cofactors (organic or ionic) in binding substrates with specificity and catalyzing transformations. Inspired by the structure–function relationship of enzymes, supramolecular self-assembly, a bottom-up approach in nanofabrication, has been employed to create enzyme-mimetic catalysts. However, accurately replicating enzymatic active sites poses a formidable challenge, primarily because of the intricacies in mimicking the complexity of natural protein folding.&lt;/p&gt;&lt;p &gt;Many natural biological systems, such as tryptophan synthase or ribosomes, rely on the association of multiple component subunits, each maintaining its structural integrity, to enable efficient and versatile functionalities. The hierarchical self-assembly principles observed in these systems have inspired us to design and self-assemble complementary molecular building blocks that form individual folding or aggregating structures, allowing for precise control over the distribution of reactive groups to create enzyme-like active sites. The customization of either component without disrupting folding structures enables the flexible engineering of catalytic properties. This Account will primarily focus on employing the self-assembly of multiple molecular components, drawing from research progress in our lab, to construct enzyme-mimetic catalysts with built-in metal-dependent or metal-free active sites. The structure–function relationship of these catalysts will be highlighted.&lt;/p&gt;&lt;p &gt;To fabricate metal-dependent enzymatic sites, such as heme pockets or copper sites, within the synthetic materials, we create a supramolecular scaffold for stabilizing hemin or forming a copper cluster, followed by the introduction of a second component to enhance substrate adsorption or metal reactivity. The resulting enzyme mimics exhibit remarkable synergistic catalytic activities and possess great stability against the harsh conditions, such as high temperatures, high ionic strength, and cyclic acidification/neutralization treatment. They can be engineered to possess tailorable selectivity toward specific chirality or sizes of substrates and can be externally stimulated to switch between ON/OFF states. These mimics have shown great performances in the sensing of biomolecules of interest, biomass degradation, and aiding in the understanding of the catalytic mechanism of native enzymes. To achieve metal-free catalysis, we introduce a “driving” component to the catalytic component to guide the formation of the assemblies mimicking the activity of hydrolases, photodecarboxylase, or photo-oxidase, with applications in peptide modifications or antibacterial therapy. Moreover, organized components like histidine can ","PeriodicalId":72040,"journal":{"name":"Accounts of materials research","volume":"5 9","pages":"1072–1086 1072–1086"},"PeriodicalIF":14.0,"publicationDate":"2024-07-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142326315","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Iron Oxide Nanomaterials at Interfaces for Sustainable Environmental Applications","authors":"Mandeep Singh Bakshi*,&nbsp;","doi":"10.1021/accountsmr.4c0015110.1021/accountsmr.4c00151","DOIUrl":"https://doi.org/10.1021/accountsmr.4c00151https://doi.org/10.1021/accountsmr.4c00151","url":null,"abstract":"&lt;p &gt;Surface active iron oxide nanoparticles (NPs) belong to a novel class of nanomaterials with an inherent ability to adsorb at interfaces and perform diverse applications. Over the last several years, bulk soluble iron oxide NPs have emerged as one of the most prominent materials for environmental and biological applications. Bulk solubility unintentionally contributes toward the toxicity of nanomaterials with largely unknown consequences. Surface active NPs provide a viable solution and limit the toxicity by restricting their action to the interface. That enhances their applicability in the extraction processes across the immiscible interfaces frequently used in water purification as well as in biological systems. This Account summarizes the characteristic features of these applications elegantly accomplished by the surface active iron oxide NPs without even being incorporated in the aqueous bulk.&lt;/p&gt;&lt;p &gt;Surface activity of iron oxide NPs is achieved through hydrothermal synthesis by carefully selecting ionic Gemini surfactants that meticulously control crystal growth as well as provide colloidal stabilization. Both headgroup polarity and hydrophobicity of Gemini surfactants adsorbed on the surface of magnetic NPs are instrumental in generating precise surface activity, which mainly depends on the appropriate hydrophilic–lipophilic balance (HLB). Such a protocol produces highly surface active small crystalline iron oxide NPs of ∼10 nm functionalized with Gemini surfactants that only adsorb at immiscible interface and do not incorporate in bulk.&lt;/p&gt;&lt;p &gt;Surface active iron oxide NPs efficiently extract Au and Ag NPs as model nanometallic pollutants from aqueous bulk, which are otherwise difficult to extract by conventional filtration techniques. Extraction can be accomplished through specific and host–guest interactions operating between functionalized surface active magnetic NPs and nanometallic pollutants. Gemini surfactant functionalized magnetic NPs act as excellent vehicles for the extraction of protein fractions from aqueous bulk. Amphiphilicity of such NPs very well differentiates between the extraction efficiency of predominantly hydrophobic and hydrophilic protein fractions. Remarkably, magnetic NPs are also fully capable of extracting blood cells without inducing hemolytic anemia when functionalized with cyclodextrins (CD), which encapsulate sugar moieties of membrane proteins or the lipid bilayer of the cell membrane.&lt;/p&gt;&lt;p &gt;Extraction can be quantitatively monitored with simple techniques such as UV–visible and dynamic light scattering in real time. Highly sophisticated imaging and spectroscopic studies elucidate the mechanistic steps traced by the surface functionalities of both magnetic NPs and extracted species. Surface activity of magnetic NPs also makes their separation and quantification much easier under the effect of an external magnetic field for their reusability as sustainable nanomaterials. Separation of nanometallic poll","PeriodicalId":72040,"journal":{"name":"Accounts of materials research","volume":"5 8","pages":"1000–1012 1000–1012"},"PeriodicalIF":14.0,"publicationDate":"2024-07-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://pubs.acs.org/doi/epdf/10.1021/accountsmr.4c00151","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142039514","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}