Now showing items 1-20 of 1544

    • Efficient and simultaneous capture of iodine and methyl iodide achieved by a covalent organic framework

      Xie, Yaqiang; Pan, Tingting; Lei, Qiong; Chen, Cailing; Dong, Xinglong; Yuan, Youyou; Maksoud, Walid Al; Zhao, Long; Cavallo, Luigi; Pinnau, Ingo; Han, Yu (Nature Communications, Springer Science and Business Media LLC, 2022-05-24) [Article]
      Radioactive molecular iodine (I2) and organic iodides, mainly methyl iodide (CH3I), coexist in the off-gas stream of nuclear power plants at low concentrations, whereas few adsorbents can effectively adsorb low-concentration I2 and CH3I simultaneously. Here we demonstrate that the I2 adsorption can occur on various adsorptive sites and be promoted through intermolecular interactions. The CH3I adsorption capacity is positively correlated with the content of strong binding sites but is unrelated to the textural properties of the adsorbent. These insights allow us to design a covalent organic framework to simultaneously capture I2 and CH3I at low concentrations. The developed material, COF-TAPT, combines high crystallinity, a large surface area, and abundant nucleophilic groups and exhibits a record-high static CH3I adsorption capacity (1.53 g·g−1 at 25 °C). In the dynamic mixed-gas adsorption with 150 ppm of I2 and 50 ppm of CH3I, COF-TAPT presents an excellent total iodine capture capacity (1.51 g·g−1), surpassing various benchmark adsorbents. This work deepens the understanding of I2/CH3I adsorption mechanisms, providing guidance for the development of novel adsorbents for related applications.
    • Three-dimensional stacked filter (3DSF): a nonlinear filter for series images of TEM

      Huang, Siyuan; Li, Hai; Jin, Chuanhong; Li, Xinghua; Wang, Jianglin; Cai, Xin; Han, Yu; Lin, Fang (Ultramicroscopy, Elsevier BV, 2022-05-23) [Article]
      Denoising is a key issue for quantitative high-resolution transmission electron microscopy (HRTEM) and its roles become more critical for applications in beam-sensitive materials and dynamic characterizations where the attainable signal-to-noise ratio (SNR) of HRTEM images is often limited. In this article, we introduce a novel nonlinear filter where a series of HRTEM images is stacked into a 3D data cube and then treated with Wiener filter in 3D domain with suitable fitting parameters. Comparing to the frequently used Winer filter that was performed for each individual image, this novel filter, denoted as 3DSF, exhibits higher SNR, less artifacts, and more computation efficiency, which works particularly well for TEM images comprising of periodic information and feature similarities in sequent micrographs within the 3D data cube. Application of this novel 3DSF is further demonstrated in a few examples that includes to capture the defect dynamics in graphene and elegant structure of MOFs.
    • Engineering kesterite based photocathode for photoelectrochemical ammonia synthesis from NOx reduction

      Zhou, Shujie; Sun, Kaiwen; Toe, Cui Ying; Yin, Jun; Huang, Jialiang; Zeng, Yiyu; Zhang, Doudou; Chen, Weijian; Mohammed, Omar F.; Hao, Xiaojing; Amal, Rose (Advanced Materials, Wiley, 2022-05-23) [Article]
      Ammonia is a key chemical feedstock for industry as well as future carbon-free fuel and transportable vector for renewable energy. Photoelectrochemical (PEC) ammonia synthesis from NOx reduction reaction (NOx RR) provides not only a promising alternative to the energy-intensive Haber-Bosch process through direct solar-to-ammonia conversion, but a sustainable solution for balancing the global nitrogen cycle by restoring ammonia from wastewater. In this work, we, for the first time, demonstrated selective ammonia synthesis from PEC NOx RR by kesterite (Cu2 ZnSnS4 (CZTS)) photocathode through loading defect-engineered TiOx cocatalyst on CdS/CZTS photocathode (TiOx /CdS/CZTS). The uniquely designed photocathode enables selective ammonia production from NOx RR, yielding up to 89.1% faradaic efficiency (0.1 V versus reversible hydrogen electrode (RHE)) with a remarkable positive onset potential (0.38 V versus RHE). By tailoring the amount of surface defective Ti3+ species, the adsorption of reactant NO3- and * NO2 intermediate is significantly promoted while the full coverage of TiOx also suppresses NO2- liberation as a by-product, contributing to high ammonia selectivity. Our further attempted PEC ammonia synthesis from simulated wastewater shows good faradaic efficiency of 64.9%, unveiling the potential of using kesterite based photocathode for sustainably restoring ammonia from nitrate-rich wastewater.
    • Highly Potassiophilic Graphdiyne Skeletons Decorated with Cu Quantum Dots Enable Dendrite-Free Potassium Metal Anodes

      Yi, Yuyang; Li, Jiaqiang; Gao, Zhixiao; Liu, Wenfeng; Zhao, Yu; Wang, Menglei; Zhao, Wen; Han, Yu; Sun, Jingyu; Zhang, Jin (Advanced Materials, Wiley, 2022-05-20) [Article]
      Employing Al foil current collector at the potassium anode side is an ideal choice to entail low-cost and high-energy potassium metal battery (PMB). Nevertheless, the poor affinity between potassium and planar Al can cause uneven K plating/stripping and hence undermined anode performance, which remains a significant challenge to be addressed. Herein, we propose a nitrogen-doped carbon@graphdiyne (NC@GDY) modified Al current collector affording potassiophilic properties that simultaneously suppresses the dendrite growth and prolongs the lifespan of K anodes. The thin and light modification layer (7 μm thick, with a mass loading of 500 μg cm<sup>-2</sup> ) is fabricated by directly growing GDY nanosheets interspersed by Cu quantum dots on NC polyhedron templates. As a result, symmetric cell tests reveal that the K@NC@GDY-Al electrode exhibits an unprecedented cycle life of over 2400 h at a 40% depth of discharge. Even at an 80% depth of discharge, the cell can still sustain for 850 h. When paired with a potassium Prussian blue cathode, thus-assembled full cell demonstrates comparable capacity and rate performance with the state-of-the-art PMBs.
    • Continuous extraction and concentration of secreted metabolites from engineered microbes using membrane technology

      Overmans, Sebastian; Ignacz, Gergo; Beke, Aron K.; Xu, Jiajie; Saikaly, Pascal; Szekely, Gyorgy; Lauersen, Kyle J. (Green Chemistry, Royal Society of Chemistry (RSC), 2022-05-18) [Article]
      Microalgal cultivation in photobioreactors and membrane separations are both considered sustainable processes. Here we explore their synergistic combination to extract and concentrate a heterologous sesquiterpenoid produced by engineered green algal cells. A hydrophobic hollow-fiber membrane contactor was used to allow interaction of culture broth and cells with a dodecane solvent phase to accumulate algal produced patchoulol. Subsequent continuous membrane extraction of patchoulol from dodecane enabled product concentration in a methanol stream as well as dodecane recovery for its reuse. A structure-based prediction using machine learning was used to model a process whereby 100% patchoulol recovery from dodecane could be achieved with solvent-resistant nanofiltration membranes. Solvent consumption, E-factor, and economic sustainability were assessed and compared with existing patchoulol production processes. Our extraction and product purification process offers six- and two-orders of magnitude lower solvent consumption compared to synthetic production and thermal-based separation, respectively. Our proposed methodology is transferable to other microbial systems for the isolation of high-value isoprenoid and hydrocarbon products.
    • Soft perovskites stabilized by robust heterojunctions

      Wu, Zhifang; Alsalloum, Abdullah; Mohammed, Omar F.; Bakr, Osman (Joule, Elsevier BV, 2022-05-18) [Article]
      Rapid progress has recently been made in the development of perovskite solar cells (PSCs) with power conversion efficiencies (PCEs) that are now comparable with those of crystalline Si, the traditional and well-established solar cell technology. Recently in Science, Fang and co-workers reported a PSC in an inverted configuration with a high efficiency of >24% (23.5% certified) and remarkable operational stability. In this work, robust heterojunctions were constructed at the interface to suppress ion migration and favorably adjust the interfacial energy band alignment, addressing two major issues associated with the poor PCEs and stability of inverted PSCs.
    • Holey Reduced Graphene Oxide Scaffolded Heterocyclic Aramid Fibers with Enhanced Mechanical Performance

      Li, Jiaqiang; Wen, Yeye; Xiao, Zhihua; Wang, Shijun; Zhong, Lixiang; Li, Tao; Jiao, Kun; Li, Lanying; Luo, Jiajun; Gao, Zhenfei; Li, Shuzhou; Zhang, Zhong; Zhang, Jin (Advanced Functional Materials, Wiley, 2022-05-17) [Article]
      Poly(p-phenylene-benzimidazole-terephthalamide) (PBIA) fibers, a kind of heterocyclic aramid fibers, possess extraordinary mechanical properties and advanced applications in aerospace, military protection, and other civilian areas. However, harsh application scenarios are putting forward even stringent requirements for the mechanical performances and environmental compatibility of PBIA fibers. Strengthening lateral interactions between polymer chains are approachable methods but ongoing challenges to obtain PBIA fibers with high-performance. This work develops a novel holey reduced-graphene-oxide (HrGO)/PBIA composite fiber with a scaffolded structure, in which the HrGO plays a role of clamp to effectively band plentiful PBIA chains through the in-plane holes. A small amount of HrGO (0.075 wt%) is able to improve the tensile strength and Young's modulus of HrGO/PBIA fibers by 11.5% and 8.3%, respectively. The small amount of well dispersed HrGO improves the crystallinity and serves as the topological constraint that enhances the lateral interaction of the PBIA chains, which is unveiled by the wide-angle X-ray scattering and the coarse-grained molecular dynamics simulations. In addition, the favorable compatibility of HrGO/PBIA fibers in complex application scenarios is demonstrated by the dynamic and cyclic-loading measurements.
    • Photoactivated p-Doping of Organic Interlayer Enables Efficient Perovskite/Silicon Tandem Solar Cells

      Zheng, Xiaopeng; Liu, Jiang; Liu, Tuo; Aydin, Erkan; Chen, Min; Yan, Wenbo; de Bastiani, Michele; Allen, Thomas; Yuan, Shuai; Kirmani, Ahmad R.; Baustert, Kyle N.; Salvador, Michael; Turedi, Bekir; Alsalloum, Abdullah Yousef; Almasabi, Khulud M.; Kotsovos, Konstantinos; Gereige, Issam; Liao, Liang-Sheng; Luther, Joseph; Graham, Kenneth R.; Mohammed, Omar F.; De Wolf, Stefaan; Bakr, Osman (ACS Energy Letters, American Chemical Society (ACS), 2022-05-17) [Article]
      Solution-processed organic semiconductor layers on rough surfaces tend to vary widely in thickness, significantly hindering charge extraction in relevant optoelectronic devices. Herein, we report the photoactivated p-doping of hole-transporting material (HTM) to enhance hole extraction for (textured) perovskite/silicon tandem solar cells, making the device performance less sensitive to the variation of hole transport layer thickness. We used the ionic compound 4-isopropyl-4′-methyldiphenyliodonium tetrakis(penta-fluorophenyl-borate) (DPI-TPFB) as a p-type dopant in poly(triaryl amine) (PTAA), which we used as the HTM. We observed that light soaking DPI-TPFB-doped PTAA shows approximately 22 times higher conductivity compared with an undoped PTAA film, which translated into an improved fill factor (FF) for tandem solar cells. Our tandem solar cells achieved an ∼80% FF and 27.8% efficiency and operated at their maximum power point for 200 h without loss of performance, in addition to retaining ∼83% of initial performance over a month of operation in an outdoor environment.
    • Separation of ethyltoluene isomers by nonporous adaptive crystals of perethylated and perbromoethylated pillararenes

      Wang, M.; Fang, S.; Yang, S.; Li, Q.; Khashab, Niveen M.; Zhou, J.; Huang, F. (Materials Today Chemistry, Elsevier BV, 2022-05-10) [Article]
      The separation of p-ethyltoluene (PET) and m-ethyltoluene (MET) is one of the most challenging steps to isolate PET from C9 aromatic compounds due to their very close boiling points. Many kinds of separation methods have been developed, but they involve low efficiency and great energy consumption. Herein, we investigate the adsorptive properties of perethylated pillar[5]arene (EtP5), perethylated pillar[6]arene (EtP6), perbromoethylated pillar[5]arene (BrP5) and perbromoethylated pillar[6]arene (BrP6) for ethyltoluene isomers. Results show that EtP6 and BrP5 crystals separate PET from a PET/MET equimolar mixture with purities of 95.4% and 92.0%, respectively. Both of them show no decrease in selectivity upon cycling for 5 times. Relatively, EtP5 and BrP6 crystals fail in this separation due to poor PET capture ability and low selectivity, respectively.
    • Nerve Network-Inspired Solid Polymer Electrolytes (NN-SPE) for Fast and Single-Ion Lithium Conduction

      Li, Zhen; Guo, Dong; Li, Fan; Hou, Guangjin; Liu, Xiaowei; Li, Chunyang; Cao, Li; Wei, Ruicong; Zhou, Zongyao; Lai, Zhiping (Energy Storage Materials, Elsevier BV, 2022-05-04) [Article]
      The low lithium-ion conductivity is current the bottleneck in developing solid-state electrolytes (SSEs) that are expected to be a key component in the next generation of lithium batteries. Inspired by the high connectivity of the biological nerve network, we designed a mimic architecture inside a polymer electrolyte to provide fast lithium-ion pathways. Detailed experimental and simulation studies revealed that the mimic nerve network could efficiently form the bi-continuous structure at very low percolation threshold, and rendered an unprecedentedly non-linear increment by order of magnitudes in the lithium-ion conductivity, with a superior lithium-ion conductivity up to 0.12 mS•cm−1, transference number up to 0.974 and robust mechanical strength of 10.3 MPa. When applied in lithium metal batteries, good rate and cycling performance were achieved at both room and elevated temperatures.
    • Evaluating the High-Pressure Volumetric CH4, H2, and CO2 Storage Properties of Denser-Version Isostructural soc-Metal–Organic Frameworks

      Ubaid, Siyad; Assen, Ayalew H.; Alezi, Dalal; Cairns, Amy; Eddaoudi, Mohamed; Belmabkhout, Youssef (Journal of Chemical & Engineering Data, American Chemical Society (ACS), 2022-04-25) [Article]
      The MOF platform based on soc topology showed recent developments for gas storage applications. soc-MOFs with very open structures, such as Al-soc-MOF-1, exhibited promising gravimetric storage performance but with compromised volumetric capacities. However, the volumetric capacity is a critical parameter to consider for vehicles such as trucks. The practical constraints under such circumstances are mainly linked to the tank volume required to accommodate adsorbents. In this work, the gas storage performances of dense soc-MOFs assembled from different metal precursors and 3,3′,5,5′-azobenzene tetracarboxylic acid, denoted as In-soc-MOF-1a, In-soc-MOF-1b, In-soc-MOF-1c, Ga-soc-MOF-1a, Fe-soc-MOF-1a, Fe-soc-MOF-1b, and Al-soc-MOF-1d, with 1a, 1b, 1c, and 1d representing NO3–, Cl–, Br–, and HO– counterions, respectively, were evaluated. Using the crystallographic densities of each MOF, volumetric uptakes were calculated from gravimetric values. The volumetric CH4, H2, and CO2 uptakes of the soc-MOFs showed a gain in storage capacity upon using denser versions, with a higher CH4 uptake of Fe-soc-MOF-1b (128 g L–1 at 50 bar) than the extended analogs (∼120 g L–1 for Fe-PBPTA-soc-MOF). The counteranions were also observed to have an impact on the volumetric capacities, with In-soc-MOF-1c > In-soc-MOF-1b > In-soc-MOF-1a for CH4 and the reverse order for H2 capacities. The performances are also comparable to those of most of the previously reported benchmark MOFs.
    • Tailoring interfacial microenvironment of palladium-zeolite catalysts for the efficient low-temperature hydrodeoxygenation of vanillin in water

      Ran, Jiansu; Alfilfil, Lujain; Li, Jingwei; Yangcheng, Ruixue; Liu, Zhaohui; Wang, Qin; Cui, Yuntong; Cao, Tong; Qiao, Min; Yao, Kexin; Zhang, Daliang; Wang, Jianjian (ChemCatChem, Wiley, 2022-04-22) [Article]
      Efficient low-temperature hydrodeoxygenation (HDO) of lignin derivatives to produce biofuels and high value-added chemicals is still of challenge. Here, we have constructed a high active and stable 0.2 wt.% Pd/MS-HZSM-5(30) catalyst, and 94.7% yield of 2-methoxy-4-methylphenol (MMP) can be achieved in HDO of vanillin (VAN, a typical platform molecule of lignin derivatives) under milder reaction conditions (60 °C, 5 h, molar ratio of VAN/Pd = 1200, water phase), outperforming the most works reported recently. Detailed experimental and mechanistic studies demonstrated that the superior catalytic performance was due to the rapid hydrogenolysis of generated intermediate (vanillyl alcohol, VAL) to MMP proceeded in an interfacial microenvironmental created by Pd NPs and acidic sites in Pd/MS-HZSM-5(30). These new insights will provide potential guidance for the efficient low-temperature production of biofuels and valuable chemicals from lignin derivatives or raw lignin.
    • Crystalline Porphyrazine-Linked Fused Aromatic Networks with High Proton Conductivity.

      Im, Yoon-Kwang; Lee, Dong-Gue; Noh, Hyuk-Jun; Yu, Soo-Young; Mahmood, Javeed; Lee, Sang-Young; Baek, Jong-Beom (Angewandte Chemie (International ed. in English), Wiley, 2022-04-20) [Article]
      Fused aromatic networks (FANs) have been studied in efforts to overcome the low physicochemical stability of metal–organic frameworks (MOFs) and covalent organic frameworks (COFs), while preserving crystallinity. Herein, we describe the synthesis of a highly stable and crystalline FAN (denoted as Pz-FAN) using pyrazine-based building blocks to form porphyrazine (Pz) linkages via an irreversible reaction. Unlike most COFs and FANs, which are synthesized from two different building blocks, the new Pz-FAN is formed using a single building block by self-cyclotetramerization. Controlled and optimized reaction conditions result in a highly crystalline Pz-FAN with physicochemical stability. The newly prepared Pz-FAN displayed a high magnitude (1.16×10−2 S cm−1) of proton conductivity compared to other reported FANs and polymers. Finally, the Pz-FAN-based membrane was evaluated for a proton-exchange membrane fuel cell (PEMFC), which showed maximum power and current densities of 192 mW cm−2 and 481 mA cm−2, respectively.
    • Low-Dose Electron Microscopy Imaging of Electron Beam-Sensitive Crystalline Materials

      Lv, Jia; Zhang, Hui; Zhang, Daliang; Liu, L. M.; Han, Yu (Accounts of Materials Research, American Chemical Society (ACS), 2022-04-19) [Article]
      As one of the most widely used characterization tools in materials science, (scanning) transmission electron microscopy ((S)TEM) has the unique ability to directly image specimens with atomic resolution. Compared to diffraction-based techniques, the main advantage of (S)TEM imaging is that in addition to the periodic average structures of crystalline materials, it can be used to probe nonperiodic local structures such as surfaces, interfaces, dopants, and defects, which have crucial impacts on material properties. However, many crystalline materials are extremely sensitive to electron beam irradiation, which can only withstand dozens (or even fewer) of electrons per square angstrom before they undergo structural damage. Although using electron doses lower than the thresholds can in principle preserve their structures, the thus acquired images are too noisy to be useful. Consequently, high-resolution imaging of the inherent structures of such electron beam-sensitive materials using (S)TEM is a long-standing challenge. In recent years, the advances in electron detectors and image-acquisition methods have enabled high-resolution (S)TEM with ultralow electron doses, largely overcoming this challenge. A series of highly electron beam-sensitive materials that are traditionally considered impossible to be imaged with (S)TEM, including metal organic frameworks (MOFs), covalent organic frameworks (COFs), organic–inorganic hybrid halide perovskites, and supramolecular crystals, have been successfully imaged at atomic resolutions. This technological advance has greatly expanded the application range of electron microscopy. This Account focuses on our recent works pertaining to the high-resolution imaging of electron beam-sensitive materials using very low electron doses. We first explain that the use of direct-detection electron-counting (DDEC) cameras provides the hardware basis for successful low-dose high-resolution TEM (HRTEM). Subsequently, we introduce a suite of methods to address the challenges peculiar to low-dose HRTEM, including rapid search for crystal zone axes, precise alignment of the image stack, and accurate determination of the defocus value. These methods, combined with the use of a DDEC camera, ensure efficient imaging of electron beam-sensitive crystalline materials in the TEM mode. Moreover, we demonstrate that integrated differential phase contrast STEM (iDPC-STEM) is an effective method for acquiring directly interpretable atomic-resolution images under low-dose conditions. In addition, we share our views on the great potential of four-dimensional STEM (4D-STEM) in imaging highly electron beam-sensitive materials and provide preliminary simulation results to demonstrate its feasibility. Finally, we discuss the significance of developing (S)TEM specimen preparation techniques applicable for sensitive materials and the advantages of using the cryogenic focused ion beam (cryo-FIB) technique for this purpose.
    • Co–Fe–B Nanochain Electrocatalysts for Oxygen Evolution at High Current Density

      Patil, Komal; Babar, Pravin Tukaram; Li, Xue; Karade, Vijay; Kim, Sugil; Jang, Su Young; Bhoite, Pravin; Kim, Jin Hyeok (ACS Applied Nano Materials, American Chemical Society (ACS), 2022-04-19) [Article]
      Constructing earth-abundant, robust, and cheap-to-make electrode materials for the oxygen evolution reaction (OER) is crucial for the practical application of hydrogen energy. In this work, we prepare amorphous cobalt iron boride (Co–Fe–B) nanochains on a nickel foam (labeled as Co–Fe–B/NF) via one-pot sodium borohydride reduction of Co2+ and Fe2+ at room temperature and use them to boost the performance of OER. The as-prepared Co–Fe–B nanochains exhibit promising catalytic activity with low overpotentials of 270 and 280 mV at higher current densities of 50 and 100 mA cm–2, respectively, and a much lower Tafel slope of 36 mV dec–1 for OER. In addition, the Co–Fe–B shows excellent stability for more than 50 h at a high current density of 100 mA cm–2. The satisfactory electrocatalytic performance is mainly due to the synergy between the metal ions (Co and Fe) and plentiful catalytically active sites of the one-dimensional chain-like structure, which improves the atom utilization efficiency
    • Ionic covalent organic nanosheet (iCON)–quaternized polybenzimidazole nanocomposite anion-exchange membranes to enhance the performance of membrane capacitive deionization

      McNair, Robert; Kumar, Sushil; Wonanke, A. D.Dinga; Addicoat, Matthew A.; Dryfe, Robert A.W.; Szekely, Gyorgy (Desalination, Elsevier BV, 2022-04-19) [Article]
      Membrane capacitive deionization (MCDI) is a promising technique to achieve desalination of low-salinity water resources. The primary requirements for developing and designing materials for MCDI applications are large surface area, high wettability to water, high conductivity, and efficient ion-transport pathways. Herein, we synthesized ionic covalent organic nanosheets (iCONs) containing guanidinium units that carry a positive charge. A series of quaternized polybenzimidazole (QPBI)/iCON (iCON@QPBI) nanocomposite membranes was fabricated using solution casting. The surface, thermal, wettability, and electrochemical properties of the iCON@QPBI nanocomposite membranes were evaluated. The iCON@QPBI anion-exchange membranes achieved a salt adsorption capacity as high as 15.6 mg g−1 and charge efficiency of up to 90%, which are 50% and 20% higher than those of the pristine QPBI membrane, respectively. The performance improvement was attributed to the increased ion-exchange capacity (2.4 mmol g−1), reduced area resistance (5.4 Ω cm2), and enhanced hydrophilicity (water uptake = 32%) of the iCON@QPBI nanocomposite membranes. This was due to the additional quaternary ammonium groups and conductive ion transport networks donated by the iCON materials. The excellent desalination performance of the iCON@polymer nanocomposite membranes demonstrated their potential for use in MCDI applications and alternative electromembrane processes.
    • Installation of synergistic binding sites onto porous organic polymers for efficient removal of perfluorooctanoic acid

      Liu, Xiongli; Zhu, Changjia; Yin, Jun; Li, Jixin; Zhang, Zhiyuan; Li, Jinli; Shui, Feng; You, Zifeng; Shi, Zhan; Li, Baiyan; Bu, Xian-He; Nafady, Ayman; Ma, Shengqian (Nature communications, Springer Science and Business Media LLC, 2022-04-19) [Article]
      Herein, we report a strategy to construct highly efficient perfluorooctanoic acid (PFOA) adsorbents by installing synergistic electrostatic/hydrophobic sites onto porous organic polymers (POPs). The constructed model material of PAF-1-NDMB (NDMB = N,N-dimethyl-butylamine) demonstrates an exceptionally high PFOA uptake capacity over 2000 mg g−1, which is 14.8 times enhancement compared with its parent material of PAF-1. And it is 32.0 and 24.1 times higher than benchmark materials of DFB-CDP (β-cyclodextrin (β-CD)-based polymer network) and activated carbon under the same conditions. Furthermore, PAF-1-NDMB exhibits the highest k2 value of 24,000 g mg−1 h−1 among all reported PFOA sorbents. And it can remove 99.99% PFOA from 1000 ppb to <70 ppt within 2 min, which is lower than the advisory level of Environmental Protection Agency of United States. This work thus not only provides a generic approach for constructing PFOA adsorbents, but also develops POPs as a platform for PFOA capture
    • Gold–Silver Bimetallic Alloy Nanoparticles in a Covalent Organic Framework for Real-Time Monitoring of Hydrogen Peroxide from Live Cells

      Arul, Ponnusamy; Huang, Sheng Tung; Mani, Veerappan; Huang, Chih-Hung (ACS Applied Nano Materials, American Chemical Society (ACS), 2022-04-18) [Article]
      An efficient and simple way has been described to prepare gold and silver bimetallic alloy nanoparticles (Au-AgNPs) in an organic framework with a metal-free core. The growth of alloy Au-AgNPs was monitored by UV–visible spectroscopy (UV–vis) and confirmed using various spectral, microscopy, and electrochemical techniques. The field-emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM) results revealed that the covalent organic framework (COF) had a uniform flake-like morphology, and the alloy-based Au-AgNPs had a flower-like structure. The results of X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD) indicated that Au-AgNPs are metallic in nature and highly crystalline. The surface of a glassy carbon electrode (GCE) was then modified with Au-AgNPs-COF, which was subsequently employed for enzyme-free electrochemical reduction of H2O2. The electrocatalytic cyclic voltammetry performance of the different modified electrodes was in the following order: COF (−14.82 μA) < AgNPs-COF (−26.95 μA) < AuNPs-COF (−31.78 μA) < Au-AgNPs-COF (−46.15 μA). The Au-AgNPs-COF/GCE displayed an excellent electrocatalytic activity toward reduction of H2O2, over a dynamic range of 2.0 nM–1.0 mM with a limit of detection (LOD) of 0.44 nM (S/N = 3). Furthermore, the present sensor showed appreciable selectivity, stability, and reproducibility against the reduction of H2O2. Practicality was demonstrated in fetal bovine serum (FBS), cat blood serum (CBS), and living cells (RAW 264.7)
    • Minimally-Invasive, Real-Time, Non-Destructive, Species-Independent Phytohormone Biosensor for Precision Farming

      Bu Khamsin, Abdullah; Ait Lahcen, Abdellatif; Filho, Jose De Oliveira; Shetty, Saptami; Blilou, Ikram; Kosel, Jürgen; Salama, Khaled N. (Elsevier BV, 2022-04-15) [Preprint]
      To keep up with population growth, precision farming technologies must be implemented to sustainably increase agricultural output. The impact of such technologies can be expanded by monitoring phytohormones, such as salicylic acid. In this study, we present a plant-wearable electrochemical sensor for in situ detection of salicylic acid. The sensor utilizes microneedle-based electrodes that are functionalized with a layer of salicylic acid selective magnetic molecularly imprinted polymers. The sensor’s capability to detect the phytohormone is demonstrated both in vitro and in vivo with a limit of detection of 2.74 µM and a range of detection that can reach as high as 150 µM. Furthermore, the selectivity of the sensor is verified by testing the sensor on commonly occurring phytohormones. Finally, we demonstrate the capability of the sensor to detect the onset of fungal infestation in Tobacco 5 minutes post-inoculation. This work shows that the sensor could serve as a promising platform for continuous and non-destructive monitoring in the field and as a fundamental research tool when coupled with a portable potentiostat.
    • Interface Engineering of Bi-Fluorescence Molecules for High-Performance Data Encryption and Ultralow UV-Light Detection

      Wang, Jian-Xin; Gutiérrez-Arzaluz, Luis; Yin, Jun; Maity, Partha; Zhou, Yang; Chen, Cailing; Han, Yu; Bakr, Osman; Eddaoudi, Mohamed; Mohammed, Omar F. (Advanced Optical Materials, Wiley, 2022-04-14) [Article]
      It is extremely difficult if not impossible to effectively and precisely regulate the luminescence of organic chromophores from different electronic excited states through external stimuli for use in light-conversion devices. This is mainly due to the difficulty in breaking Kasha's rule by large energy separation and stabilization of different emissive electronic excited states. Here, the authors address this great challenge in a single experiment by expanding the utility of a monounsaturated omega-9 fatty acid (oleic acid) capped with organic chromophores as a new and efficient luminescent regulator. More specifically, the authors have successfully promoted the use of oleic acid as an efficient and reversible switch that can precisely regulate chromophore luminescence. These time-resolved absorption and luminescence experiments, along with density functional theory calculations have clearly demonstrated that ultrafast electron transfer from oleic acid to the difluoroboron β-diketonate (DFBK) chromophores efficiently blocks the intramolecular charge transfer process of DFBK chromophores, and activates the locally excited state luminescence, leading to different emission colors from different electronic excited states for ultralow UV-light detection and high-performance data encryption.