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542 results on '"Arandiyan, Hamidreza"'

160. Controlled Direct Growth of Polymer Shell on Upconversion Nanoparticle Surface via Visible Light Regulated Polymerization

Author

Bagheri, Ali, Arandiyan, Hamidreza, Adnan, Nik Nik M., Boyer, Cyrille, and Lim, May

Abstract

Lanthanide-doped upconversion nanoparticles (UCNPs) have unique photoluminescent properties that are useful in many biomedical applications. Modification of UCNPs with a polymer layer can confer additional functionality such as biocompatibility, stability in vivo, or drug delivery capability. It is also important that the modification process can be controlled precisely and without having adverse effects on the UCNPs luminescence properties. Herein, a polymer shell was grafted directly from the surface of UCNPs (grafting from) via visible light (λmax= 635 nm, 0.7 mW/cm2) regulated photoenergy/electron transfer–reversible addition fragmentation chain transfer polymerization (PET-RAFT). The polymerization kinetics, grafting density, and thickness of the surface-tethered polymer chains can be tuned precisely by adjusting the monomer and RAFT agent ratio or the light exposure time. This approach also permits temporal control of the polymerization process. That is, the polymerization process can be initiated, halted, or terminated by switching the light source on and off. By limiting the non-radiative decay caused by surface defects, as well as from vibrational deactivation from solvents, the polymer shell enhanced the upconversion luminescence of the silica-coated UCNPs. This investigation paves the way for the development of UCNPs with controlled properties for various application requirements.

Published
2024
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161. Solar Light Responsive Poly(vinyl alcohol)-Assisted Hydrothermal Synthesis of Immobilized TiO2/Ti Film with the Addition of Peroxymonosulfate for Photocatalytic Degradation of Ciprofloxacin in Aqueous Media: A Mechanistic Approach

Author

Sayed, Murtaza, Khan, Javed Ali, Shah, Luqman Ali, Shah, Noor S., Shah, Faheem, Khan, Hasan M., Zhang, Pengyi, and Arandiyan, Hamidreza

Abstract

This study is focused on the synthesis of a solar light driven novel poly(vinyl alcohol) (PVA)-assisted TiO2/Ti film via a facile one pot hydrothermal technique and then its photocatalytic applications by adding with peroxymonosulfate (PMS) for efficient degradation of ciprofloxacin (CIP). The key hydrothermal synthesis parameters like PVA-content, hydrothermal time (HT), and pH were optimized. The best photocatalytic performance of the synthesized material was observed when prepared with the conditions of PVA = 8 mg, HT= 3 h, and pH = 2.62. Results showed that 98.3% of CIP was degraded within 60 min by PVA-assisted TiO2/Ti film with 0.5 mM PMS added, compared to 89.38% and 88.86% degradation with 0.5 mM persulfate (PS) and 0.5 mM hydrogen peroxide (H2O2), respectively. The photocatalytic degradation of CIP by PVA-assisted TiO2/Ti film with PMS added was dependent on the [PMS]0and increased with increase in [PMS]0. The kappvalues at [PMS]0of 0.2, 0.5, 0.8, and 1.0 mM were 0.029, 0.0582, 0.068, and 0.128 min–1, respectively. The photocatalytic degradation of CIP by PVA-assisted TiO2/Ti film with PMS added under solar light irradiation was highly dependent on the [pH]0as well as on the presence of coexisting anions like HCO3–, CO32–, NO2–, Cl–, and SO42–. Natural organic matter (NOM) retarded the photocatalytic degradation of CIP by PVA-assisted TiO2/Ti film with PMS added under solar light irradiation due to its strong scavenging ability toward •OH and SO4•–. The photocatalytic degradation of CIP by as-prepared photocatalyst under solar light irradiation was higher in Milli-Q water (kapp= 0.0582 min–1) than tap water (kapp= 0.0342 min–1) followed by river water (kapp= 0.0259 min–1) and then synthetic wastewater (kapp= 0.0212 min–1). The degradation products of CIP were investigated by UPLC-MS/MS, and accordingly degradation pathways were proposed. Moreover, the mineralization, ecotoxicity, and cyclic photocatalytic stability of the as-prepared photocatalyst were also investigated. These findings suggest that as-prepared PVA-assisted TiO2/Ti film with PMS added is a promising alternative for the treatment of wastewater containing antibiotics.

Published
2024
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162. Engineering Surface Structure and Defect Chemistry of Nanoscale Cubic Co3O4 Crystallites for Enhanced Lithium and Sodium Storage.

Author

Liu, Yanguo, Wan, Haicheng, Zhang, Hongzhi, Chen, Jiayuan, Fang, Fang, Jiang, Nan, Zhang, Wanxing, Zhou, Fangwang, Arandiyan, Hamidreza, Wang, Yuan, Liu, Guanyu, Wang, Zhiyuan, Luo, Shaohua, Chen, Xiaobo, and Sun, Hongyu

Abstract

Transition metal oxide nanostructures are drawing much attention as promising electrodes for advanced rechargeable batteries. However, due to the intrinsic low electronic conductivity and substantial volume change during cycling, the electrodes usually show low rate capability and poor cycling life. Herein, we report a route combining surface/interface engineering and defect chemistry to tune the lithium storage properties in nanoscale cubic Co3O4 crystallites. The Co3O4 crystallites were annealed in an inert atmosphere by carefully controlling the temperature, which induces the conformal formation of CoO layers with a tunable thickness on the surface of initial cubes. Microstructural characterizations and electrochemical measurements indicate that the optimized sample possesses a CoO thickness of ∼1.1 nm and shows a reversible lithium storage capacity of 1069.4 mAh·g–1 after 100 cycles of a current density of 0.1 A·g–1. A capacity of 807.9 mAh·g–1 can be obtained at a rate of 5 A·g–1. The improved lithium storage performance is attributed to the unique CoO–Co3O4 interface structure and defect chemistry, which induces a strong electric field at the sharp Co3O4–CoO interface according to density functional theory calculations. The optimized sample also shows it improved sodium storage properties. This work thus provides an effective strategy for the design and synthesis of advanced electrode materials for energy applications. [ABSTRACT FROM AUTHOR]

Published
2020
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163. Assembly of cerium-based coordination polymer into variant polycrystalline 2D–3D CeO2−x nanostructures.

Author

S. Mofarah, Sajjad, Adabifiroozjaei, Esmaeil, Wang, Yuan, Arandiyan, Hamidreza, Pardehkhorram, Raheleh, Yao, Yin, Assadi, M. Hussein N., Mehmood, Rashid, Chen, Wen-Fan, Tsounis, Constantine, Scott, Jason, Lim, Sean, Webster, Richard, Zhong, Vicki, Xu, Yuwen, Koshy, Pramod, and Sorrell, Charles C.

Abstract

Precise control over the morphology of nanomaterials is critical yet challenging. The present work reports an efficient approach to tailor the architecture of nanostructures. The process involves rapid disassembly/reassembly of an unstable metal-based coordination polymer (MCP) by controlling the kinetics of the reassembly process. The synthesis procedure delivers unprecedented polycrystalline nanostructures, e.g., holey 2D CeO2−x nanosheets, with precisely tailored thicknesses in the range of 10–100 nm, and hollow 3D pseudo-octahedra and spheres. The consequent high surface areas and pore volumes, short diffusion distances, and high defect densities of the holey 2D CeO2−x indicate significant densities of active sites. This holey architecture exhibits rapid CO conversion and outstanding solar light photocatalytic performance. This approach of directed assembly offers a template-free, controllable, and cost-effective approach to achieve engineered CeO2−x architectures, which are nearly impossible through existing approaches. [ABSTRACT FROM AUTHOR]

Published
2020
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181. Solar Light Responsive Poly(vinyl alcohol)-Assisted Hydrothermal Synthesis of Immobilized TiO2/Ti Film with the Addition of Peroxymonosulfate for Photocatalytic Degradation of Ciprofloxacin in Aqueous Media: A Mechanistic Approach

Author

Sayed, Murtaza, primary, Khan, Javed Ali, additional, Shah, Luqman Ali, additional, Shah, Noor S., additional, Shah, Faheem, additional, Khan, Hasan M., additional, Zhang, Pengyi, additional, and Arandiyan, Hamidreza, additional

Published
2017
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183. Comparison on the Performance of α-Fe2O3 and γ-Fe2O3 for Selective Catalytic Reduction of Nitrogen Oxides with Ammonia

Author

Huazhen Chang, Shijian Yang, Lei Ma, Junhua Li, Caixia Liu, Arandiyan Hamidreza, and Yue Peng

Subjects
Ammonia, chemistry.chemical_compound, Adsorption, chemistry, Inorganic chemistry, Selective catalytic reduction, General Chemistry, Nitrogen oxides, Catalysis, Organometallic chemistry
Abstract

γ-Fe2O3 catalyst showed higher catalytic activity than α-Fe2O3 in 150–300 °C. Both NH3 and NO x species adsorbed and reacted easily on γ-Fe2O3. However, NH3 adsorbed on α-Fe2O3 and then reacted with gaseous NO x . Gaseous NO x was more easily adsorbed on α-Fe2O3 than gaseous NH3, consequently, stable nitrates formed and blocked the active sites, which affected the SCR reaction badly.

Published
2013

185. In Situ Production of Graphene–Fiber Hybrid Structures

Author

Akia, Mandana, primary, Cremar, Lee, additional, Chipara, Mircea, additional, Munoz, Edgar, additional, Cortez, Hilario, additional, de Santiago, Hector, additional, Rodriguez-Macias, Fernando J., additional, Vega-Cantú, Yadira I., additional, Arandiyan, Hamidreza, additional, Sun, Hongyu, additional, Lodge, Timothy P., additional, Mao, Yuanbing, additional, and Lozano, Karen, additional

Published
2017
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193. Reduced methylammonium triple-cation Rb0.05(FAPbI3)0.95(MAPbBr3)0.05 perovskite solar cells based on a TiO2/SnO2 bilayer electron transport layer approaching a stabilized 21% efficiency: the role of antisolvents

Author

Mali, Sawanta S., Patil, Jyoti V., Arandiyan, Hamidreza, and Hong, Chang Kook

Abstract

Due to their high efficiency and stability, triple-cation based perovskite solar cells (PSCs) have now crossed 23% power conversion efficiency (PCE). However, the perovskite composition and type of the electron transport layer (ETL) play a key role in improving their performance. Therefore, in the present investigation, high quality TiO2/SnO2 bilayer ETLs and thermally stable reduced methylammonium (MA) cation based triple-cation perovskite layers are used to fabricate thermally stable PSCs. By retaining their normal (n–i–p) device architecture, the influence of antisolvents on the perovskite layer has been investigated in detail. Systematic studies in this work reveal that the amorphous SnO2/TiO2 bilayer and the trifluorotoluene (TFT) processed perovskite layer significantly influence the current density and open circuit voltage (VOC) and reduce the charge recombination of perovskite devices. The optimised devices having micrometer size grains exhibited ＞20.5 ± 0.5% PCE for a thermally stable Rb0.05(FAPbI3)0.95(MAPbBr3)0.05 perovskite composition with a SnO2/TiO2 bilayer ETL. Furthermore, the SnO2:TiO2 bilayer ETL-containing PSCs are thermally stable for more than 200 hours at 80 °C. [ABSTRACT FROM AUTHOR]

Published
2019
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194. How Do Structurally Distinct Au/a-Fe2O3 Interfaces Determine Surface OH/H2O reactivity, Intermediate Evolution, and Product Formation in Low-temperature Water-gas Shift Reaction?

Author

Lingli Gu, Yiqiang Zeng, Yina Feng, Wu Jiang, Weijie Ji, Arandiyan, Hamidreza, and Chak-Tong Au

Subjects
WATER gas shift reactions, WATER-gas, INTERMEDIATE goods, WATER temperature, BIOLOGICAL evolution, LOW temperatures, WATER
Abstract

Three structurally distinct interfaces, i. e. Au/α-Fe2O3-THB-Air, Au/α-Fe2O3-HS-Air, and Au/α-Fe2O3-QC-Air, with the major substrate facet being {113}, {001}, and {012} respectively, were controllably prepared. The low temperature water gas shift (WGS) reaction (100-260 °C) was applied to these unique systems to reveal how these structurally distinct interfaces can impact on the reaction behavior. With the detailed performance evaluation plus the characterizations of CO-TPSR, XPS, and in situ-FTIR in particular, the correlations between the evolution of different intermediates and the distinct catalytic behaviors have been established. The substrate facet structure and the Au entity largely determine the form and reactivity of surface OH/ H2O species which in turn determine the formation of different intermediates and eventually the product formation. The Au/α-Fe2O3-THB-Air is enriched with oxygen vacant sites, favorable for dissociative adsorption of H2O, carboxyl intermediate formation and H2 production. The Au/α-Fe2O3-HS-Air is enriched with surface lattice oxygen, favorable for molecular adsorption of H2O, formate intermediate formation, and CO2 production. The Au/α-Fe2O3-QC-Air interface is enriched with surface Fe sites, favorable for dissociative adsorption of H2O and evolution of stable carboxyl intermediate as well as isolated OH species at low reaction temperatures. The findings are informative to control the interfacial structure for the WGS and other reactions. [ABSTRACT FROM AUTHOR]

Published
2019
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