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Ying W, Liu Q, Jin X, Ding G, Liu M, Wang P, Chen S. Magnetic Carbon Quantum Dots/Iron Oxide Composite Based on Waste Rice Noodle and Iron Oxide Scale: Preparation and Photocatalytic Capability. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:2506. [PMID: 37764535 PMCID: PMC10536646 DOI: 10.3390/nano13182506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 08/28/2023] [Accepted: 09/04/2023] [Indexed: 09/29/2023]
Abstract
To provide an economical magnetic photocatalyst and introduce an innovative approach for efficiently utilizing discarded waste rice noodle (WRN) and iron oxide scale (IOS), we initially converted WRN into carbon quantum dots (CQDs) using a hydrothermal method, simultaneously calcining IOS to obtain iron oxide (FeOx). Subsequently, we successfully synthesized a cost-effective, magnetic CQDs/FeOx photocatalytic composite for the first time by combining the resulting CQDs and FeOx. Our findings demonstrated that calcining IOS in an air atmosphere enhanced the content of photocatalytically active α-Fe2O3, while incorporating WRN-based CQDs into FeOx improved the electron-hole pair separation, resulting in increased O2 reduction and H2O oxidation. Under optimized conditions (IOS calcination temperature: 300 °C; carbon loading: 11 wt%), the CQDs/FeOx composite, utilizing WRN and IOS as its foundation, exhibited exceptional and reusable capabilities in photodegrading methylene blue and tetracycline. Remarkably, for methylene blue, it achieved an impressive degradation rate of 99.30% within 480 min, accompanied by a high degradation rate constant of 5.26 × 10-3 min-1. This composite demonstrated reusability potential for up to ten photocatalytic cycles without a significant reduction in the degradation efficiency, surpassing the performance of IOS and FeOx without CQDs. Notably, the composite exhibited strong magnetism with a saturation magnetization strength of 34.7 emu/g, which enables efficient and convenient recovery in photocatalytic applications. This characteristic is highly advantageous for the large-scale industrial utilization of photocatalytic water purification.
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Affiliation(s)
| | | | | | | | | | | | - Shuoping Chen
- College of Materials Science and Engineering, Guilin University of Technology, Guilin 541004, China; (W.Y.); (Q.L.); (X.J.); (G.D.); (M.L.); (P.W.)
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Li AB, Miroshnik L, Rummel BD, Balakrishnan G, Han SM, Sinno T. A unified theory of free energy functionals and applications to diffusion. Proc Natl Acad Sci U S A 2022; 119:e2203399119. [PMID: 35648830 PMCID: PMC9191674 DOI: 10.1073/pnas.2203399119] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Accepted: 04/20/2022] [Indexed: 11/18/2022] Open
Abstract
SignificanceThe free energy functional is a central component of continuum dynamical models used to describe phase transitions, microstructural evolution, and pattern formation. However, despite the success of these models in many areas of physics, chemistry, and biology, the standard free energy frameworks are frequently characterized by physically opaque parameters and incorporate assumptions that are difficult to assess. Here, we introduce a mathematical formalism that provides a unifying umbrella for constructing free energy functionals. We show that Ginzburg-Landau framework is a special case of this umbrella and derive a generalization of the widely employed Cahn-Hilliard equation. More broadly, we expect the framework will also be useful for generalizing higher-order theories, establishing formal connections to microscopic physics, and coarse graining.
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Affiliation(s)
- Andrew B. Li
- Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19146
| | - Leonid Miroshnik
- Chemical & Biological Engineering, University of New Mexico, Albuquerque, NM 87131
| | - Brian D. Rummel
- Chemical & Biological Engineering, University of New Mexico, Albuquerque, NM 87131
| | - Ganesh Balakrishnan
- Center for High Technology Materials, University of New Mexico, Albuquerque, NM 87131
| | - Sang M. Han
- Chemical & Biological Engineering, University of New Mexico, Albuquerque, NM 87131
- Center for High Technology Materials, University of New Mexico, Albuquerque, NM 87131
| | - Talid Sinno
- Chemical & Biomolecular Engineering, University of Pennsylvania, Philadelphia, PA 19146
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Mahale P, Moradifar P, Cheng HY, Nova NN, Grede AJ, Lee B, De Jesús LR, Wetherington M, Giebink NC, Badding JV, Alem N, Mallouk TE. Oxide-Free Three-Dimensional Germanium/Silicon Core-Shell Metalattice Made by High-Pressure Confined Chemical Vapor Deposition. ACS NANO 2020; 14:12810-12818. [PMID: 32941002 DOI: 10.1021/acsnano.0c03559] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Metalattices are crystalline arrays of uniform particles in which the period of the crystal is close to some characteristic physical length scale of the material. Here, we explore the synthesis and properties of a germanium metalattice in which the ∼70 nm periodicity of a silica colloidal crystal template is close to the ∼24 nm Bohr exciton radius of the nanocrystalline Ge replica. The problem of Ge surface oxidation can be significant when exploring quantum confinement effects or designing electronically coupled nanostructures because of the high surface area to volume ratio at the nanoscale. To eliminate surface oxidation, we developed a core-shell synthesis in which the Ge metalattice is protected by an oxide-free Si interfacial layer, and we explore its properties by transmission electron microscopy (TEM), Raman spectroscopy, and electron energy loss spectroscopy (EELS). The interstices of a colloidal crystal film grown from 69 nm diameter spherical silica particles were filled with polycrystalline Ge by high-pressure confined chemical vapor deposition (HPcCVD) from GeH4. After the SiO2 template was etched away with aqueous HF, the Ge replica was uniformly coated with an amorphous Si shell by HPcCVD as confirmed by TEM-EDS (energy-dispersive X-ray spectroscopy) and Raman spectroscopy. Formation of the shell prevents oxidation of the Ge core within the detection limit of XPS. The electronic properties of the core-shell structure were studied by accessing the Ge 3d edge onset using STEM-EELS. A blue shift in the edge onset with decreasing size of Ge sites in the metalattices suggests quantum confinement of the Ge core. The degree of quantum confinement of the Ge core depends on the void sizes in the template, which is tunable by using silica particles of varying size. The edge onset also shows a shift to higher energy near the shell in comparison with the Ge core. This shift along with the observation of Ge-Si vibrational modes in the Raman spectrum indicate interdiffusion of Ge and Si. Both the size of the voids in the template and core-shell interdiffusion of Si and Ge can in principle be tuned to modify the electronic properties of the Ge metalattice.
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Affiliation(s)
- Pratibha Mahale
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Parivash Moradifar
- Department of Material Science and Engineering & Material Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Hiu Yan Cheng
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Nabila Nabi Nova
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Alex J Grede
- Department of Electrical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Byeongdu Lee
- Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439, United States
| | - Luis R De Jesús
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
| | - Maxwell Wetherington
- Material Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Noel C Giebink
- Department of Electrical Engineering, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - John V Badding
- Department of Material Science and Engineering & Material Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
- Department of Chemistry, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Nasim Alem
- Department of Material Science and Engineering & Material Research Institute, The Pennsylvania State University, University Park, Pennsylvania 16802, United States
| | - Thomas E Mallouk
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104, United States
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