Recent Submissions

  • Fast water transport and molecular sieving through ultrathin ordered conjugated-polymer-framework membranes

    Shen, Jie; Cai, Yichen; Zhang, Chenhui; Wei, Wan; Chen, Cailing; Liu, Lingmei; Yang, Kuiwei; Ma, Yinchang; Wang, Yingge; Tseng, Chien-Chih; Fu, Jui-Han; Dong, Xinglong; Li, Jiaqiang; Zhang, Xixiang; Li, Lain-Jong; Jiang, Jianwen; Pinnau, Ingo; Tung, Vincent; Han, Yu (Nature Materials, Springer Science and Business Media LLC, 2022-08-08) [Article]
    The development of membranes that block solutes while allowing rapid water transport is of great importance. The microstructure of the membrane needs to be rationally designed at the molecular level to achieve precise molecular sieving and high water flux simultaneously. We report the design and fabrication of ultrathin, ordered conjugated-polymer-framework (CPF) films with thicknesses down to 1 nm via chemical vapour deposition and their performance as separation membranes. Our CPF membranes inherently have regular rhombic sub-nanometre (10.3 × 3.7 Å) channels, unlike membranes made of carbon nanotubes or graphene, whose separation performance depends on the alignment or stacking of materials. The optimized membrane exhibited a high water/NaCl selectivity of ∼6,900 and water permeance of ∼112 mol m−2 h−1 bar−1, and salt rejection >99.5% in high-salinity mixed-ion separations driven by osmotic pressure. Molecular dynamics simulations revealed that water molecules quickly and collectively pass through the membrane by forming a continuous three-dimensional network within the hydrophobic channels. The advent of ordered CPF provides a route towards developing carbon-based membranes for precise molecular separation.
  • Low-voltage ultrafast nonvolatile memory via direct charge injection through a threshold resistive-switching layer

    Li, Yuan; Zhang, Zhi Cheng; Li, Jiaqiang; Chen, Xu-Dong; Kong, Ya; Wang, Fu-Dong; Zhang, Guo-Xin; Lu, Tong-Bu; Zhang, Jin (Nature communications, Springer Science and Business Media LLC, 2022-08-06) [Article]
    The explosion in demand for massive data processing and storage requires revolutionary memory technologies featuring ultrahigh speed, ultralong retention, ultrahigh capacity and ultralow energy consumption. Although a breakthrough in ultrafast floating-gate memory has been achieved very recently, it still suffers a high operation voltage (tens of volts) due to the Fowler-Nordheim tunnelling mechanism. It is still a great challenge to realize ultrafast nonvolatile storage with low operation voltage. Here we propose a floating-gate memory with a structure of MoS2/hBN/MoS2/graphdiyne oxide/WSe2, in which a threshold switching layer, graphdiyne oxide, instead of a dielectric blocking layer in conventional floating-gate memories, is used to connect the floating gate and control gate. The volatile threshold switching characteristic of graphdiyne oxide allows the direct charge injection from control gate to floating gate by applying a nanosecond voltage pulse (20 ns) with low magnitude (2 V), and restricts the injected charges in floating gate for a long-term retention (10 years) after the pulse. The high operation speed and low voltage endow the device with an ultralow energy consumption of 10 fJ. These results demonstrate a new strategy to develop next-generation high-speed low-energy nonvolatile memory.
  • Unblocking Ion-occluded Pore Channels in Poly(triazine imide) Framework for Proton Conduction

    Chi, Heng-Yu; Chen, Cailing; Zhao, Kangning; Villalobos, Luis Francisco; Schouwink, Pascal Alexander; Piveteau, Laura; Marshall, Kenneth Paul; Liu, Qi; Han, Yu; Agrawal, Kumar Varoon (Angewandte Chemie (International ed. in English), 2022-07-30) [Article]
    Poly(triazine imide) or PTI is an ordered graphitic carbon nitride hosting Å-scale pores attractive for selective molecular transport. AA'-stacked PTI layers are synthesized by ionothermal route during which ions occupy the framework and occlude the pores. Synthesis of ion-free PTI hosting AB-stacked layers has been reported, however, pores in this configuration are blocked by the neighboring layer. The unavailability of open pore limits application of PTI in molecular transport. Herein, we demonstrate acid treatment for ion depletion which maintains AA' stacking and results in open pore structure. We provide first direct evidence of ion-depleted open pores by imaging with the atomic resolution using integrated differential phase-contrast scanning transmission electron microscopy. Depending on the extent of ion-exchange, AA' stacking with open channels and AB stacking with closed channels are obtained and imaged for the first time. The accessibility of open channels is demonstrated by enhanced proton transport through ion depleted PTI.
  • Aggregation-Induced Fluorescence Enhancement for Efficient X-ray Imaging Scintillators and High-Speed Optical Wireless Communication

    Wang, Jian-Xin; Wang, Yue; Nadinov, Issatay; Yin, Jun; Gutierrez Arzaluz, Luis; Alkhazragi, Omar; He, Tengyue; Ng, Tien Khee; Eddaoudi, Mohamed; Alshareef, Husam N.; Bakr, Osman; Ooi, Boon S.; Mohammed, Omar F. (ACS Materials Letters, American Chemical Society (ACS), 2022-07-29) [Article]
    Aggregation of some chromophores generates very strong fluorescence signals due to the tight molecular packing and highly restricted vibrational motions in the electronically excited states. Such an aggregation-induced emission enhancement enables great strides in biomedical imaging, security screening, sensing, and light communication applications. Here, we realized efficient utilization of a series of aggregation-induced emission luminogens (AIEgens) in X-ray imaging scintillators and optical wireless communication (OWC) technology. Ultrafast time-resolved laser spectroscopic experiments and high-level density functional theory (DFT) calculations clearly demonstrate that a significant increase in the rotational energy barrier in the aggregated state of AIEgens is observed, leading to highly restricted molecular vibrations and suppressed nonradiative processes. AIEgen-based scintillators exhibit a high X-ray imaging resolution of 16.3 lp mm–1, making them excellent candidates for X-ray radiography and security inspections. In addition, these AIEgens show a broad -3-dB modulation bandwidth of ∼110 MHz and high net data rates of ∼600 Mb/s, demonstrating their high potential for application in the field of high-speed OWC.
  • Smartphone-Based Multiplexed Biosensing Tools for Health Monitoring

    Beduk, Tutku; Beduk, Duygu; Hasan, Mohd Rahil; Guler Celik, Emine; Kosel, Jurgen; Narang, Jagriti; Salama, Khaled N.; Timur, Suna (Biosensors, MDPI AG, 2022-07-29) [Article]
    Many emerging technologies have the potential to improve health care by providing more personalized approaches or early diagnostic methods. In this review, we cover smartphone-based multiplexed sensors as affordable and portable sensing platforms for point-of-care devices. Multiplexing has been gaining attention recently for clinical diagnosis considering certain diseases require analysis of complex biological networks instead of single-marker analysis. Smartphones offer tremendous possibilities for on-site detection analysis due to their portability, high accessibility, fast sample processing, and robust imaging capabilities. Straightforward digital analysis and convenient user interfaces support networked health care systems and individualized health monitoring. Detailed biomarker profiling provides fast and accurate analysis for disease diagnosis for limited sample volume collection. Here, multiplexed smartphone-based assays with optical and electrochemical components are covered. Possible wireless or wired communication actuators and portable and wearable sensing integration for various sensing applications are discussed. The crucial features and the weaknesses of these devices are critically evaluated.
  • Rich Indium-Vacancies In2S3 with Atomic p–n Homojunction for Boosting Photocatalytic Multifunctional Properties

    Liu, Yuxin; Chen, Cailing; He, Yiqiang; Zhang, Zhe; Li, Mingbian; Li, Chunguang; Chen, Xiao-Bo; Han, Yu; Shi, Zhan (Small, Wiley, 2022-07-27) [Article]
    Design and development of highly efficient photocatalytic materials are key to employ photocatalytic technology as a sound solution to energy and environment related challenges. This work aims to significantly boost photocatalytic activity through rich indium vacancies (VIn) In2S3 with atomic p–n homojunction through a one-pot preparation strategy. Positron annihilation spectroscopy and electron paramagnetic resonance reveal existence of VIn in the prepared photocatalysts. Mott–Schottky plots and surface photovoltage spectra prove rich VIn In2S3 can form atomic p–n homojunction. It is validated that p–n homojunction can effectively separate carriers combined with photoelectrochemical tests. VIn decreases carrier transport activation energy (CTAE) from 0.64 eV of VIn-poor In2S3 to 0.44 eV of VIn-rich In2S3. The special structure endows defective In2S3 with multifunctional photocatalysis properties, i.e., hydrogen production (872.7 µmol g−1 h−1), degradation of methyl orange (20 min, 97%), and reduction in heavy metal ions Cr(VI) (30 min, 98%) under simulated sunlight, which outperforms a variety of existing In2S3 composite catalysts. Therefore, such a compositional strategy and mechanistic study are expected to offer new insights for designing highly efficient photocatalysts through defect engineering.
  • Highly selective molecular sieving of cis- over trans-1,2-dichloroethene isomers

    Liu, Xin; Alimi, Lukman Olawale; Khashab, Niveen M. (Chemical Communications, Royal Society of Chemistry (RSC), 2022-07-27) [Article]
    An intrinsically porous trianglimine macrocycle 1 is reported to display energy-efficient and cost-effective adsorptive properties by selectively separating cis-1,2-dichloroethene (cis-DCE) from an equimolar cis- and trans-DCE mixture with a purity of over 96%. The selectivity is enhanced by host/guest C–H⋯π intermolecular interactions. Moreover, the macrocycle can be reused many times without any decrease in performance, which further supports the sustainability of using molecular sieves in chemical separation.
  • High-Performance Copper-Doped Perovskite-Related Silver Halide X-ray Imaging Scintillator

    He, Tengyue; Zhou, Yang; Wang, Xiaojia; Yin, Jun; Gutierrez Arzaluz, Luis; Wang, Jian-Xin; Zhang, Yuhai; Bakr, Osman; Mohammed, Omar F. (ACS Energy Letters, American Chemical Society (ACS), 2022-07-26) [Article]
    Scintillators are critical for high-energy radiation detection across a wide array of potential applications, from medical radiography and safety inspections all the way to space exploration. However, constrained by their current shortcomings, including high-temperature and complex fabrication as well as inherent brittleness and fragility among thick films and bulk crystals, traditional scintillators are finding it difficult to meet the rising demand for cost-effective, ecofriendly, and flexible X-ray detection. Here, we describe the development of high-performance and flexible X-ray scintillators based on films of Cu-doped Cs2AgI3 that exhibit ultrahigh X-ray sensitivity. The materials exhibit a high scintillation light yield of up to 82 900 photons/MeV and a low detection limit of 77.8 nGy/s, which is approximately 70 times lower than the dosage for a standard medical examination. Moreover, richly detailed X-ray images of biological tissue and electronic components with a high spatial resolution of 16.2 lp/mm were obtained using flexible, large-area, solution-processed scintillation screens.
  • Novel Tpms Contactors Designed with Imprinted Porosity: Numerical Evaluation of Momentum and Energy Transport

    Grande, Carlos; Asif, Mohammad (Elsevier BV, 2022-07-25) [Preprint]
    Structured packings in reactors and separation processes have an extensive trait for process intensification such as enhancement in mass and heat transport without having any substantial pressure drop and can now successfully be produced by using additive manufacturing methods such as 3D printing. Structured packings manufactured with Triply Periodical Minimum Surfaces (TPMS) have good mixing properties and enhanced thermal transport, but they do not have high surface areas.In this work, we report a new type of hybrid TPMS structures with high surface area while keeping good mixing properties. The new shapes are made by generating solids on the boundaries of a 2D tessellation of polygons over the TPMS surface. The new shapes have a higher surface area than a TPMS and at the same time, a higher porosity. We have evaluated the pressure drop and heat transfer properties of such structures for Reynolds numbers 1-200 in ten different solids. The results indicate that pressure drop is dominated by porosity. Heat transfer properties however depend also on available surface area and thus are improved in the porous structures.
  • Maximizing Active Fe Species in ZSM-5 Zeolite Using Organic-Template-Free Synthesis for Efficient Selective Methane Oxidation

    Cheng, Qingpeng; Li, Guanna; Yao, Xueli; Zheng, Lirong; Wang, Junhu; Emwas, Abdul-Hamid M.; Castaño, Pedro; Ruiz-Martinez, Javier; Han, Yu (Research Square Platform LLC, 2022-07-22) [Preprint]
    The selective oxidation of CH4 in the aqueous phase to produce valuable chemicals has attracted considerable research attention due to its mild reaction conditions and simple process. As the most widely studied catalyst for this reaction, Fe-containing ZSM-5 zeolite (Fe-ZSM-5) demonstrates high intrinsic activity and selectivity; however, Fe-ZSM-5 prepared using conventional methods has a limited number of active Fe sites, resulting in low CH4 conversion per unit mass of the catalyst. To address this issue, this study reports a facile organic-template-free synthesis strategy that enables the incorporation of more Fe into the zeolite framework with a higher dispersion degree compared to conventional synthesis methods. Because framework Fe incorporated in this way is more readily to transform into isolated extra-framework Fe species under thermal treatment, the overall effect is that Fe-ZSM-5 prepared using this method (Fe-HZ5-TF) has three times as many catalytically active sites as conventional Fe-ZSM-5. When used for the selective oxidation of CH4 (30.5 bar) with 0.5 M H2O2 at 75°C, Fe-HZ5-TF produced a record high C1 oxygenate yield of 106.3 mmol gcat−1 h− 1 (a HCOOH selectivity of 91.3%), surpassing other catalysts reported to date. Spectroscopic characterization and density functional theory calculations revealed that the active sites in Fe-HZ5-TF are mononuclear Fe species in the form of [(H2O)3Fe(IV) = O]2+ bound to Al pairs in the zeolite framework. This differs from conventional Fe-ZSM-5, where binuclear Fe acts as the active site. Analysis of the catalyst and product evolution during the reaction suggests a radical-driven pathway to explain CH4 activation at the mononuclear Fe site and subsequent conversion to C1 oxygenates.
  • New era of sustainable design for molecular motors

    Szekely, Gyorgy (Chem Catalysis, Elsevier BV, 2022-07-21) [Article]
    Native lignocellulose can be used to create light-driven molecular motors via a “green” synthetic approach. In the May issue of Green Chemistry, Barta, Feringa, and co-workers provided new insights into the sustainable design of molecular motors through reductive catalytic fractionation using a lignocellulose platform.
  • Decreasing the Coking and Deactivation of a Reforming Ni-Ce/Al2o3 Catalyst with Intraparticle Sic in Hydrogen Production Routes

    Tavares, F.; Mohamed, Hend Omar; Kulkarni, Shekhar Rajabhau; Morlanes, Natalia Sanchez; Castaño, Pedro (Elsevier BV, 2022-07-19) [Preprint]
    Steam reforming processes are under pressure to fuel the hydrogen economy, cutting its significant carbon footprint and transitioning to renewable feedstock while improving catalyst performance and lifetime. A seemingly inert material, such as silicon carbide (SiC, also known as carborundum), introduced in catalytic particles significantly influences catalytic performance, particularly during deactivation. We synthesized different catalysts with similar amounts of active materials (20 wt% of Ni and 2 wt% of Ce) and varied the proportion (0 to 78 wt%) and particle size (38 to 112 µm) of SiC within the alumina support. We used various techniques to characterize the catalysts and test them in reforming heptane, which was employed as the model molecule. The maximum enhancement with SiC occurs using 20 wt% of SiC with a size of 38 µm. Further, the enhancement with SiC is due to the control of the Ni particle size, leading to a 26% improvement in the apparent reaction rate (per exposed Ni) and a 117% decline in the deactivation rate compared to the SiC-free counterpart.
  • Scalable Fabrication of Solvent-Free Composite Solid Electrolyte by a Continuous Thermal-Extrusion Process

    Li, Zhen; Aboalsaud, Ammar M.; Liu, Xiaowei; Thankamony, Roshni; Chen, I-Chun; Li, Yangxing; Lai, Zhiping (Journal of Colloid and Interface Science, Elsevier BV, 2022-07-19) [Article]
    Composite solid-state electrolytes (CSEs) are regarded as a promising alternative for the next-generation lithium-ion batteries because they integrate the advantages of inorganic electrolytes and organic electrolytes. However, there are two issues faced by current CSEs: 1) a green and feasible approach to prepare CSEs in large scales is desired; and 2) the trace solvents, remaining from the preparation processes, lead to some serious concerns, such as safety hazard issues, electrolyte-electrode interfacial issues, and reduced durability of batteries. Here, a continuous thermal-extrusion process is presented to realize the large-scale fabrication of solvent-free CSE. A 38.7-meter CSE membrane was prepared as a demonstration in this study. Thanks to the elimination of residual solvents, the electrolyte membrane exhibited a high tensile strength of 3.85 MPa, satisfactory lithium transference number (0.495), and excellent electrochemical stability (5.15 V). Excellent long-term stability was demonstrated by operating the symmetric lithium cell at a stable current density of 0.1 mA cm−2 for over 3700 h. Solvent-free CSE lithium metal batteries showed a discharge capacity of 155.7 – 25.17 mAh g-1 at 0.1 – 2.0 C, and the discharge capacity remained 78.1% after testing for 380 cycles.
  • Tailoring novel polymer/UTSA-16 hybrid aerogels for efficient CH4/CO2 separation

    Atzori, Cesare; Porcaro, Natale G.; Crocellà, Valentina; Bonino, Francesca; Signorile, Matteo; Antico, Pasqualmorica; Daniel, Christophe; Venditto, Vincenzo; Grande, Carlos A.; Bordiga, Silvia (Microporous and Mesoporous Materials, Elsevier BV, 2022-07-19) [Article]
    A significant number of industrially relevant separation processes involves the removal of carbon dioxide (CO2), as the purification of natural gas (CO2/CH4 separation). In this scenario, the development of new adsorbents with a real technological future for CO2 separation, i.e with a high separation efficiency, good mechanical properties and easy to handle, is of primary importance. In the present work, novel composite monolithic aerogels containing the UTSA-16 metal organic framework as the active phase and porous crystalline polymers (namely syndiotactic polystyrene and polyphenyloxide) as binders were successfully synthesized and fully characterized. The adsorption capacity of such novel aerogels towards CO2 and CH4 was tested at low pressure and variable temperature, allowing the evaluation of their CO2/CH4 selectivity. Microcalorimetric experiments provided the CO2 interaction energy and disclosed possible deformation-relaxation phenomena involving the polymeric matrix during gas adsorption. The new composites retain a very high CO2 adsorption capacity compared to the pristine UTSA-16 (around 75% at 298 K and 1 bar) and have excellent CO2 capture performances in comparison to other types of supported/printed MOFs reported in the literature. The outstanding adsorption properties and the possibility to obtain monoliths with the desired size and shape and good mechanical stability make these new composites very good candidates for efficient CO2/CH4 separation processes.
  • Engineering MOF surface defects in mixed matrix membranes: An effective strategy to enhance MOF/polymer adhesion and control interfacial gas transport

    Fan, Dong; Ozcan, Aydin; Shekhah, Osama; Semino, Rocio; Eddaoudi, Mohamed; Maurin, Guillaume (Journal of Membrane Science Letters, Elsevier BV, 2022-07-15) [Article]
    MOF/polymer adhesion in Mixed Matrix Membranes (MMMs) has been mainly enhanced so far via MOF and/or polymer functionalization to strengthen the interactions between the two components. This strategy, albeit effective, is generally accompanied by a drop in the permeability and/or selectivity performance of the MMMs. In this contribution, engineering structure defects at the MOF surfaces is proposed as an effective route to create pockets that immobilize part of the polymer chain, which is of crucial importance both to avoid plasticization issues and to enhance the MOF/polymer affinity while overcoming the adhesion/performance trade-off in MMMs. This engineered interfacial interlocking structure also serves as a bridge to accelerate the gas transport from the polymeric region towards the MOF pore entrance. This concept is showcased with a model MMM made of the prototypical UiO-66 MOF and the glassy Polymer of Intrinsic Microporosity-1 (PIM-1) and tested using CO2, CH4 and, N2 as guest species. Our computational findings reveal that a defective UiO-66 MOF surface improves the MOF/PIM-1 adhesion and contributes to accelerate the interfacial gas transport of the slender molecules CO2 and N2 and in a lesser extent of the spherical molecule CH4. This translates into a selective enhancement of the CO2 transport once combined with CH4 which paves the ways toward promising perspective for pre-combustion CO2 capture.
  • Selective palladium recovery by a highly porous polyisothiocyanurate

    Nguyen, Thien Si; Yavuz, Cafer Tayyar (Chem, Elsevier BV, 2022-07-14) [Article]
    Precious metals, particularly palladium (Pd), are in short supply, and their effective recovery from waste depends on metal-specific adsorbents that provide energy-efficient and environmentally friendly solutions. In this issue of Chem, Coskun and co-workers introduce a new porous organic polymer with exceptional porosity and stability and record-high capacity and selectivity toward Pd.
  • Lecithin Capping Ligands Enable Ultrastable Perovskite-Phase CsPbI3 Quantum Dots for Rec. 2020 Bright-Red Light-Emitting Diodes

    Mir, Wasim Jeelani; Alamoudi, Ahmed; Yin, Jun; Yorov, Khursand E.; Maity, Partha; Naphade, Rounak; Shao, Bingyao; Wang, Jiayi; Lintangpradipto, Muhammad Naufal; Nematulloev, Saidkhodzha; Emwas, Abdul-Hamid M.; Genovese, Alessandro; Mohammed, Omar F.; Bakr, Osman (Journal of the American Chemical Society, American Chemical Society (ACS), 2022-07-14) [Article]
    Bright-red light-emitting diodes (LEDs) with a narrow emission line width that emit between 620 and 635 nm are needed to meet the latest industry color standard for wide color gamut displays, Rec. 2020. CsPbI3 perovskite quantum dots (QDs) are one of the few known materials that are ideally suited to meet these criteria. Unfortunately, CsPbI3 perovskite QDs are prone to transform into a non-red-emitting phase and are subject to further degradation mechanisms when their luminescence wavelength is tuned to match that of the Rec. 2020 standard. Here, we show that zwitterionic lecithin ligands can stabilize the perovskite phase of CsPbI3 QDs for long periods in air for at least 6 months compared to a few days for control samples. LEDs fabricated with our ultrastable lecithin-capped CsPbI3 QDs exhibit an external quantum efficiency (EQE) of 7.1% for electroluminescence centered at 634 nm─a record for all-inorganic perovskite nanocrystals in Rec. 2020 red. Our devices achieve a maximum luminance of 1391 cd/m2 at 7.5 V, and their operational half-life is 33 min (T50) at 200 cd/m2─a 10-fold enhancement compared to control samples. Density functional theory results suggest that the surface strain in CsPbI3 QDs capped with the conventional ligands, oleic acid and oleylamine, contributes to the instability of the perovskite structural phase. On the other hand, lecithin binding induces virtually no surface strain and shows a stronger binding tendency for the CsPbI3 surface. Our study highlights the tremendous potential of zwitterionic ligands in stabilizing the perovskite phase and particle size of CsPbI3 QDs for various optoelectronic applications.
  • Quinuclidinium-piperidinium based dual hydroxide anion exchange membranes as highly conductive and stable electrolyte materials for alkaline fuel cell applications

    Patil, Smitha S.; V, Madhura; Kammakakam, Irshad; Swamy, MH Halashankar; Patil, K. Sadashiva; Lai, Zhiping; Rao H N, Anil (Electrochimica Acta, Elsevier BV, 2022-07-12) [Article]
    Anion-exchange membrane fuel cells (AEMFCs) utilizing quaternary ammonium functionalized poly(arylene ether sulfone)s have been rapidly advanced in the clean energy research arena. However, it is highly desirable to integrate the benefits of quaternary ammonium cations in the polymeric membrane systems to achieve a high-power output together with substantial stabilities that significantly reduce the material costs. Herein, we report the tethering of two different quinuclidinium and piperidinium cations separated by a flexible –(CH2)4˗ spacer as a dual hydroxide conductor in the poly(arylene ether sulfone)s copolymer membrane (QP-PES) for enhancing the structural and physical properties as well as the ionic conductivities. The results proved that the tethering of dual hydroxide conductor in the PES backbone led to show maximum hydroxide conductivity of 88 mS cm−1 at 80 °C while enabling a hydrophilic/hydrophobic micro-phase separation due to the presence of flexible alkyl spacer. We also investigated the properties of a single hydroxide conductor exclusively comprising the quinuclidinium cation (Q-PES) and compared it with that of QP-PES. Interestingly, both the Q-PES and QP-PES membranes displayed superior thermal, mechanical, and dimensional stabilities. Most importantly, the QP-PES membrane demonstrated excellent alkaline stability over the period of 1000 h due to the existence of dual hydroxide conductor together with alkyl spacer units. Furthermore, the maximum power density of a H2/O2 single cell using QP-PES (92.3 mWcm−2) is higher than that of QP-PES (70.0 mWcm−2). The results provide a greater perception to design the high performance AEM materials.
  • Acid-free fabrication of polyaryletherketone membranes

    Aristizábal, Sandra L.; Upadhyaya, Lakshmeesha; Falca, Gheorghe; Gebreyohannes, Abaynesh Yihdego; Aijaz, Mohammed Omer; Karim, Mohammad Rezaul; Nunes, Suzana Pereira (Journal of Membrane Science, Elsevier BV, 2022-07-09) [Article]
    Polyaryletherketones (PAEKs) are a class of ultrahigh performance polymers with outstanding temperature and chemical resistance. Poly(ether ketone ketone) copolymer (Kepstan®) and poly(ether ether ketone) (PEEK) display intrinsic insolubility in nearly all organic solvents. The primary issue for the application of these polymers is their processability which requires a high temperature/pressure-based technique, or the use of harsh and corrosive solvents, like methanesulfonic and sulfuric acid, resulting in sulfonation of the polymer backbone that adversely might affect their chemical stability. In this work, we propose a method to prepare porous Kepstan® and PEEK membranes using N-methyl-2-pyrrolidone (NMP) as solvent at room temperature. It consisted of a modification-regeneration strategy to turn commercial semi-crystalline Kepstan® and PEEK into dithiolane soluble derivatives that allow the fabrication of hollow fiber, flat-sheet, and electrospun nanofibers. The resulting membranes are then regenerated to the solvent-resistant materials. The novel Kepstan® and PEEK hollow fibers exhibited a N,N-dimethylformamide (DMF) permeance of 2.21 and 2.05 L m−2 h−2 bar−1, with more than 90% rejection of Crystal Violet (408 g mol−1) and Methyl Orange (327 g mol−1), respectively.
  • Recent Advances in Chemistry/Materials (Saudi Arabia)

    Aziz, Md. Abdul; Hossain, M. Mozahar; Mohammed, Omar F. (The Chemical Record, Wiley, 2022-07-08) [Article]
    Saudi Arabia in recent years has made considerable progress in the field of chemistry and material science, especially in topics, such as nanotechnology, energy storage, and photovoltaics. This special issue comprises high-quality contributions by researchers in the country.

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