This study presents a surface engineering strategy utilizing electronic waste (e-waste) to incorporate single-atom catalysts on conjugated polymers. Employing a conjugated porphyrin polymeric photocatalyst, gold single-atom-site catalysts are successfully introduced using the acidic metal leachates from e-waste, where metal speciation and composition are regulated during the metal loading processes. The resulting photocatalyst with gold single atoms demonstrates a remarkable hydrogen peroxide (H2O2) selectivity of up to 97.56%, yielding a pure H2O2 solution at 73.3 µm h−1 under white LED illumination. The produced H2O2 is activated to •OH radicals on the same polymer with mixed gold and iron atoms, enabling a photo-Fenton reaction and the complete degradation of toxic microcystin-LR within 10 min under visible light. This study highlights the universal applicability of the metal mining strategy in various photoreactions. It is believed that this discovery pioneers sustainable photocatalysis, allowing the tuning of reactivity and selectivity on photocatalytic surfaces using metal waste.
Solvent-Induced Reversible Guest Uptake and Release by Flexible Porous Organic Cages
Abdul Ghaffar, Muhammad Bilal Asif, Javeed Mahmood, Cafer T. Yavuz
Porous organic cages with intrinsic and extrinsic cavities offer excellent host–guest control, molecular uptake, and on-demand release without compromising the selectivity. However, dynamic control over the porosity in cage molecules remains challenging. Herein, we report a CC3 cage-based crystalline adsorbent with dynamic control over its porosity for stable adsorption and release of the probe organic molecules. Interestingly, the polymorphic forms of cages (α and β) differ in crystallographic packing with flexible orientation but retain their structure after solvation. Using this isomorphism, the CC3 adsorbent exhibited an uptake of 29.5 mg g–1 for neutral red, 39.5 mg g–1 for methyl blue, and 39 mg g–1 for both molecules. The solvent-induced phase transition selectively obstructs neutral red adsorption with 85.5% change in overall capacity. Adsorption affinity correlates strongly with surface area, while solvent choice governs selectivity, highlighting switchable porosity. These findings enable advanced adsorbents with switchable porosity and selective affinity for energy and environmental applications.
Scalable synthesis of Sb-doped Rb3InCl6 nanocrystals for high-resolution X-ray imaging screen
Azimet A. Karluk, Saidkhozha Nematulloev, Simil Thomas, Bashir E. Hasanov, Khursand Yorov, Rounak Naphade, Luis Gutie´rrez-Arzaluz, Bodiuzzaman Mohammad, Mutalifu Abulikemu, Javeed Mahmood, and Cafer T. Yavuz
Lead-free, all-inorganic halide nanocrystals hold promise for advanced devices, with chloride-based variants offering stability, tunable band gaps, and easy processing. However, these nanocrystals face synthesis challenges due to the low solubility and complex coordination of heavy metal chloride salts. The conventional ligand-assisted reprecipitation (LARP) method is incompatible with chloride-based crystals, while the hot-injection technique is slow and complex, hindering efficient synthesis and scalability. We present a modified LARP method using an acid-mediated strategy to synthesize undoped and Sb3+-doped Rb3InCl6 nanocrystals. These nanocrystals maintain colloidal stability for up to 6 months and exhibit a large Stokes shift (230 nm), a high photoluminescence quantum yield (PLQY) of 68.01%, low self-absorption, and a high light yield of 15,500 photons/MeV. The flexible nanocrystal composite film with polysulfone achieves an X-ray imaging resolution of 18.5 line pairs per millimeter (lp mm−1). The colloidal solution and film of Rb3InCl6:Sb nanocrystals exhibit strong radioluminescence and linear responses under X-ray irradiation, highlighting their potential for medical radiography.
Single crystals of organometallic manganese halides as sustainable high-luminescence materials for X-ray scintillation
Azimet A. Karluk, Simil Thomas, Aleksander Shkurenko, Javeed Mahmood, Mohamed Eddaoudi Bashir E. Hasanov, and Cafer T. Yavuz
The instability and toxicity of lead halide perovskites hinder their widespread application, despite their potential as novel X-ray materials. Organic-metal halide hybrids are promising luminescent materials with exceptional properties and low-temperature processing for cost-effective, eco-friendly, and high-performance alternatives. Here, we present lead-free, zero-dimensional hybrid halides, methyl triphenyl phosphonium manganese(II) chloride ((MTP)2MnCl4) and phenyltrimethylammonium manganese(II) chloride ((PTA)2MnCl4), grown sustainably by solution processing, in the form of large aggregated single crystals. The crystals have exceptionally high photoluminescence quantum yields of approximately 74.61% and 72.62%, showing strong green emission peaks at 512 nm and 525 nm, respectively. The crystalline materials featured 160 nm and 175 nm Stokes shifts, 40 840 and 29 500 photons per MeV high scintillation yields, and 144.65 and 594.06 nGy s−1, exceptional detection limits, respectively, revealing a self-absorption-free nature. Proving practical value, a flexible X-ray scintillator screen from a composite of poly(methyl methacrylate) and (MTP)2MnCl4 powder achieved an outstanding spatial resolution of 20 lp per mm, further cementing their viability as X-ray scintillators by being both environmentally friendly and highly effective.
Structural control over single-crystalline oxides for heterogeneous catalysis
Kim, S.-J., Maligal-Ganesh, R. V., Mahmood, J., Babar, P. & Yavuz, C. T
Nature Reviews Chemistry
2025
Oxides are integral to heterogeneous catalysis, serving critical roles such as catalyst supports, active materials and electrodes. A highly ordered subset, single-crystalline oxides, have traditionally been used as model catalyst supports in fundamental surface science studies. However, advancements in bulk synthesis have rendered their general use more feasible for real-world applications. In this review, we explore the efficiency of single-crystalline oxides as active metals and supports across a wide range of heterogeneous processes, often performing exceptionally well. Beginning with synthetic methods, we discuss the advantages of single-crystalline oxides in thermo-, electro- and photocatalysis. Previously held conventions about catalytic activity, deactivation and surface–adsorbate interactions are re-evaluated by understanding how these ordered materials behave during the respective reactions. Last, we assess advances in characterization techniques and their impact on designing the next generation of catalysts based on single-crystalline oxides.
Hierarchically Porous Poly(aryl thioether)s Through Dynamic Linker Engineering for Thiyl Radical Photocatalysis
Sunil Kumar, Doyun Kim, Youngdong Song, Bolormaa Bayarkhuu, Jueun Park, Donghee Hoh, Cafer T. Yavuz, Jeehye Byun
Hierarchically porous polymers offer large surface areas for enhanced catalytic activity, but incorporating photocatalytic sites into these pore channels remains challenging. Inspired by nature's disulfide bonds, which stabilize proteins and enable redox activity, this study introduces a hierarchically porous poly(aryl thioether) photocatalyst via dual disulfide and thioether linkages formed by polycondensation. Thiolate intermediates undergo partial oxidation in air, yielding a micro/mesoporous polymer with a 757 m2 g⁻¹ surface area, comparable to its microporous counterpart synthesized in N₂. This structure exhibits enhanced adsorption capacity, as demonstrated by tests with volatile organic compounds and mercury ions. The disulfide-functionalized pore walls enable thiyl radical formation under visible light, achieving outstanding diphenylacetylene oxidation performance. This heterogeneous photocatalyst surpasses homogeneous systems, showing >99% conversion efficiency with 3.5% apparent quantum yield at 440 nm. This study pioneers a linker engineering strategy to integrate hierarchical porous structure and photoactive radical generation in a single porous polymer photocatalyst.
Catalysts for dry reforming and methods of producing the same
US20240050933A1
Cafer Tayyar Yavuz, Seokjin Kim, Aadesh Harale, Bandar Al-Solami, Aqil Jamal
The disclosure relates to catalysts for dry reforming, methods of producing the catalysts, and methods of using the catalysts in dry reforming. The catalysts contain nickel, molybdenum and a metal oxide. The methods of producing the catalysts include adding a solvent to precipitate the catalyst, followed by removing the solvent. The solvent addition and removal steps can be repeated as desired.
Solvent-linked porous covalent organic polymers and method of preparing the same
US Patent 11,535,701,2022
Cafer T Yavuz, Vepa Rozyyev, Joo Sung Lee
Solvent-linked porous covalent organic polymers (COPs) and a method of preparing the same are described. The porous covalent organic polymers are linked by a solvent and are thus suitable for the transportation and storage of natural gas. A method of preparing the porous covalent organic polymers by conducting alkylation polymerization between an aromatic monomer and a chlorine-based solvent in the presence of a Lewis acid catalyst is described. Porous stretchable covalent organic polymers having pores with various sizes can be synthesized simply and quickly at room temperature and atmospheric pressure without a heating or purification step. The covalent organic polymers have very high natural gas storage capacity due to the flexible porous network structure thereof and thus are suitable for storage and transportation of natural gas and useful as a natural gas adsorbent.
Electroless plating solution and electroless plating method for recovering precious metal adsorbed on porous porphyrin polymer
US Patent App. 17/413,559, 2022
Jong-In Han, SON JiEun, Cafer Yavuz, HONG Youngran
The present invention relates to a method for recovering a precious metal selectively adsorbed on a porous porphyrin polymer, and to an electroless plating method capable of recovering a precious metal in a film form by desorbing and leaching the precious metal without an additional oxidizing agent and using same as a plating solution to reduce the precious metal on the surface of a substrate without an additional reducing agent.
The electrochemical plating apparatus for recovering a noble metal adsorbed to the porous polymeric porphyrin
App # 10-2018-0162180, 2018.
C. T. Yavuz, Y. Hong
The present invention relates to an apparatus and a method of electrochemical plating for recovering precious metals adsorbed on a porous porphyrin polymer, wherein precious metals selectively adsorbed on a porous porphyrin polymer is leached into an electrolyte to be collected in a film shape on a surface of a reducing electrode through electrochemical reduction reaction.COPYRIGHT KIPO 2020
Natural gas storage utilizing the elastic organic polymer covalent bond which is connected to the solvent
App # 10-2019-0058296, 2019.
C. T. Yavuz, V. Rozyyev
The present invention relates to solvent linked porous covalent organic polymers and a method for preparing the same. More particularly, the present invention relates to porous covalent organic polymers linked by a solvent, thereby being suitable for transport and storage of natural gas, and to a method for preparing the porous covalent organic polymers by adding an aromatic monomer and a chlorine-based solvent in the presence of a Lewis acid catalyst, followed by alkylation. Under the conditions of room temperature and room pressure, it is possible to synthesize porous, elastic and covalent organic polymers having pores of various sizes simply and quickly without a heating step or a purification step. Also, the covalent organic polymers can be used in various ways as an adsorbent for natural gas because the storage capacity of natural gas is very high due to a flexible porous network structure of the covalent organic polymers, thereby being suitable for transport and storage of natural gas.COPYRIGHT KIPO 2021
Methods for separating magnetic nanoparticles are provided. In certain embodiments, a method is provided for separating magnetic nanoparticles comprising: providing a sample comprising a plurality of magnetic nanoparticles; passing the sample through a first magnetic field; at least partially isolating nanoparticles of the first nanoparticle size desired; altering the strength of the first magnetic field to produce a second magnetic field; and at least partially isolating nanoparticles of the second nanoparticle size desired.
Engineered nanoparticles for water treatment application
J. Byun, C. T. Yavuz
2016
Chapter 2 in Engineered Nanoparticles and the Environment: Biophysicochemical Processes and Toxicity, Edited by B. Xing, C. D. Vecitis, N. Senesi.
WILEY-IUPAC Series in Biophysico-Chemical Processes in Environmental Systems
Published by John Wiley & Sons, Inc.
In this chapter, water treatment processes using nanoparticles and studies related to the removal of waterborne contaminants, such as anionic, cationic, and organic pollutants, will be reviewed.
Nano Rust
Cafer T. Yavuz
2008
My first book was recently published via VDM Verlag. Thanks to Gabriel Caruntu for hooking me up with them. If you're interested in buying please click here, it's only $116(!).
Here's the blurb from the back:
This work describes the first size dependent magneticseparation in nanoscale by using rust like iron oxide. Magnetite (Fe3O4) nanocrystals of high quality and uniform size (4 nm to 33 nm) were synthesized. Batch synthesis was shown to go up to 20 grams which is more than 10 times of a standard nanocrystal synthesis, without loosing the quality and monodispersity. Reactor design for mass (1 gram per hour) production of magnetite nanocrystals isreported for the first time. A green synthesis thatutilizes rust and edible oils was developed.
The cost of a kg of magnetite nanocrystals was brought down from $2600 to $22. Size dependency of magnetism was shown in nanoscale for the first time. Reversible aggregation theory was developed to explain the low field magnetic separation and solution behavior of magnetite nanocrystals. Arsenic was removed from drinking water with magnetite nanocrystals 200 times better than commercial adsorbents. Silica coating was successfully applied and magnetite - silica nanoshells were functionalized with amino groups. For the first time, silver was coated on the magnetite -silica nanoshells to produce triple multishells.
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