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Challenges in Water Electrolyzer
Challenges in Water Electrolyzer
Ru-Embedded Carbon Fabric
Ru-Embedded Carbon Fabric
Amine Chemistry of Porous CO2 Adsorbents
Amine Chemistry of Porous CO2 Adsorbents
Boronization of Nickel Foam for Sustainable Electrochemical Reduction of Nitrate to Ammonia
Boronization of Nickel Foam for Sustainable Electrochemical Reduction of Nitrate to Ammonia
How Reproducible are Surface Areas Calculated from the BET Equation?
How Reproducible are Surface Areas Calculated from the BET Equation?
Extensive Screening of Solvent-linked Porous Polymers through Friedel-Crafts Reaction for Gas Adsorption
Extensive Screening of Solvent-linked Porous Polymers through Friedel-Crafts Reaction for Gas Adsorption
Alkyl-linked porphyrin porous polymers for gas capture and precious metal adsorption
Alkyl-linked porphyrin porous polymers for gas capture and precious metal adsorption
Quantifying the nitrogen effect on CO2 capture using isoporous network polymers
Quantifying the nitrogen effect on CO2 capture using isoporous network polymers
Direct Access to Primary Amines and Particle Morphology Control in Nanoporous CO2 Sorbents
Direct Access to Primary Amines and Particle Morphology Control in Nanoporous CO2 Sorbents
Enhanced Sorption Cycle Stability and Kinetics of CO2 on Lithium Silicates Using the Lithium Ion Channeling Effect of TiO2 Nanotubes
Enhanced Sorption Cycle Stability and Kinetics of CO2 on Lithium Silicates Using the Lithium Ion Channeling Effect of TiO2 Nanotubes
  • Alkyl-linked porphyrin porous polymers for gas capture and precious metal adsorption

    Y. Hong§, V. Rozyyev§, C. T. Yavuz. §: Equal contribution
    Small Sci., 1, 6, 2000078
    2021
    Alkyl-linked porphyrin porous polymers for gas capture and precious metal adsorption
    In gas adsorption and metal recovery, inexpensive and covalently bonded porous polymers offer industrial feasibility, despite the challenge of having reactive functionalities while maintaining porosity. Herein, three highly porous covalent organic polymers (COPs), COP-210, COP-211, and COP-212, with porphyrin functionalities that are readily synthesized by a Friedel–Crafts reaction using chlorinated solvents as linkers are reported. The polymers exhibit competitive adsorption capacities for CO₂, H2, and CH4. Their porphyrin sites proved particularly effective in precious metal recovery, where COPs exhibit high selectivity toward gold, platinum, palladium, and silver. Analysis reveals that reductive metal capture is prevalent for gold and silver. Platinum is also captured through a combination of reduction and chelation. The gold adsorption capacities are 0.901–1.250 g g−1 with fast adsorption kinetics at low pH. COP-212 selectively recovers 95.6% of gold from actual electronic waste (e-waste) collected from junkyards. The results show that the inexpensive and scalable porous porphyrin polymers offer great potential in gas capture, separation, and precious metal recovery.
  • Reaction: Porous Organic Polymers for Uranium Capture

    C. T. Yavuz
    Chem, 7, 271–280
    2021
    Cafer T. Yavuz received his PhD from Rice University in 2008 with a Welch scholarship under the supervision of Vicki Colvin. He then worked as a postdoctoral scholar at the University of California, Santa Barbara, with Galen Stucky. He started his independent group in 2010 at KAIST, Korea. He is currently a professor of chemistry at the King Abdullah University of Science and Technology in Saudi Arabia. His research focuses on the design and synthesis of nanoscale and porous materials for applications in energy and the environment. He uses fine chemistry in confined spaces to enable rapid and targeted transformations of CO₂, methane, and water.
  • Asynchronous double Schiff base formation of pyrazole porous polymers for selective Pd recovery

    M. Garai§, M. Mahato§, Y. Hong, V. Rozyyev, U. Jeong, Z. Ullah, C. T. Yavuz
    Adv. Sci., 8, 2001676
    2021
    Asynchronous double Schiff base formation of pyrazole porous polymers for selective Pd recovery
    Pyrazole-linked covalent organic polymer is synthesized using an asynchronous double Schiff base from readily available monomers. The one-pot reaction features no metals as a building block or reagent, hence facilitating the structural purity and industrial scalability of the design. Through a single-crystal study on a model compound, the double Schiff base formation is found to follow syn addition, a kinetically favored product, suggesting that reactivity of the amine and carbonyls dictate the order and geometry of the framework building. The highly porous pyrazole polymer COP-214 is chemically resistant in reactive conditions for over two weeks and thermally stable up to 425 °C in air. COP-214 shows well-pronounced gas capture and selectivities, and a high CO₂/N₂ selectivity of 102. The strongly coordinating pyrazole sites show rapid uptake and quantitative selectivity of Pd (II) over several coordinating metals (especially Pt (II)) at all pH points that are tested, a remarkably rare feature that is best explained by detailed analysis as the size-selective strong coordination of Pd onto pyrazoles. Density functional theory (DFT) calculations show energetically favorable Pd binding between the metal and N-sites of COP-214. The polymer is reusable multiple times without loss of activity, providing great incentives for an industrial prospect.
  • Robust Mesoporous Zr-MOF with Pd Nanoparticles for Formic-Acid-Based Chemical Hydrogen Storage

    M. Garai, C. T. Yavuz
    Matter, 4, 10–25
    2021
    Robust Mesoporous Zr-MOF with Pd Nanoparticles for Formic-Acid-Based Chemical Hydrogen Storage
    Formic acid is a compelling chemical storage platform for hydrogen gas, but the lack of an efficient dehydrogenation catalyst is preventing its commercial use. In this issue of Matter, Wang et al. report a fine-tuned zirconium metal-organic framework with palladium nanoparticles that effectively dehydrogenates formic acid without degradation.
  • Cesium Ion-Mediated Microporous Carbon for CO2 Capture and Lithium-Ion Storage

    H. J. Lee, D. Ko, J-S. Kim, Y. Park, I. Hwang, C. T. Yavuz, J. W. Choi
    ChemNanoMat, 7, 150 –157
    2021
    Cesium Ion-Mediated Microporous Carbon for CO2 Capture and Lithium-Ion Storage
    Activated carbon has been used in a wide range of applications owing to its large specific area, facile synthesis, and low cost. The synthesis of activated carbon mostly relies on potassium hydroxide (KOH)-mediated activation which leads to the formation of micropores (<2 nm) after a washing step with acid. Here we report the preparation of activated carbon with an anomalously large surface area (3288 m2 g−1), obtained by employing an activation process mediated by cesium (Cs) ions. The high affinity of the carbon lattice for Cs ions induces immense interlayer expansion upon complexation of the intercalant Cs ion with the carbon host. Furthermore, the Cs-activation process maintains the nitrogen content of the carbon source by enabling the activation process at low temperature. The large surface area and well-preserved nitrogen content of Cs-activated carbon takes advantage of its enhanced interaction with CO₂ molecules (for superior CO₂ capture) and lithium ions (for improved Li ion storage), respectively. The present investigation unveils a new approach toward tuning the key structural properties of activated carbon; that is, controlling the affinity of the carbon host for the intercalant ion when they engage in complex formation during the activation process.
  • Light-activated Polydopamine Coatings for Efficient Metal Recovery from Electronic Wastes

    K. R. Kim, J. Kim, J. W. Kim, C. T. Yavuz, M. Y. Yang, Y. S. Nam
    Sep. Purif. Technol., 254, 117674
    2021
    Light-activated Polydopamine Coatings for Efficient Metal Recovery from Electronic Wastes
    Metal ion adsorption from industrial wastewater has received increasing attention for the elimination of heavy metals and selective recovery of precious metals. Among the precious metals found in E-waste, gold has attracted considerable attention because of its wide range of practical applications and high economic value. However, the adsorbents used at present for the recovery of precious metals have very low adsorption capacity and poor metal selectivity for commercial uses. Herein, we introduce a new photochemical route for the selective and efficient adsorption of gold ions using bio-inspired metal-philic coatings. Internal surfaces of the mesoporous polymer microspheres were coated with polydopamine via the oxidative polymerization of catecholamines. The polydopamine layer served as a selective photo-active reductant for gold ions. Under 1-sun simulated illumination, the polydopamine layer selectively reduced gold ions to generate metallic gold nuclei. Moreover, once the metallic gold nanostructures were formed, localized surface plasmon further enhanced the reduction of gold ions. The combined effects increased the maximum amount of gold ions adsorbed per unit mass of the adsorbent up to 26 times compared to that in the dark. The adsorbed metallic gold was re-dissolvable in a thiourea solution for the complete recovery of gold ions. The selectivity toward gold ions among various metal ions was demonstrated using a solution mixture containing eight different metal ions that are commonly found in industrial wastewater. Density functional theory calculations revealed that reduction of gold on the polydopamine layer was energetically favorable, while the reduction of other metal ions was not. The dramatic increase in the maximum adsorption capacity and selectivity owing to the combined effect of the photochemical activation and polyphenol chemistry renders this process a promising approach toward urban mining of novel metal ions from electronic wastes.

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