Journal Description
Crystals
Crystals
is an international, peer-reviewed, open access journal on Crystallography published monthly online by MDPI. The Professional Committee of Key Materials and Technology for Electronic Components (PC-KMTEC) is affiliated with Crystals and its members receive discounts on the article processing charges.
- Open Access— free for readers, with article processing charges (APC) paid by authors or their institutions.
- High Visibility: indexed within Scopus, SCIE (Web of Science), Inspec, CAPlus / SciFinder, and other databases.
- Journal Rank: JCR - Q2 (Crystallography) / CiteScore - Q2 (Condensed Matter Physics)
- Rapid Publication: manuscripts are peer-reviewed and a first decision is provided to authors approximately 10.6 days after submission; acceptance to publication is undertaken in 2.7 days (median values for papers published in this journal in the second half of 2023).
- Recognition of Reviewers: reviewers who provide timely, thorough peer-review reports receive vouchers entitling them to a discount on the APC of their next publication in any MDPI journal, in appreciation of the work done.
Impact Factor:
2.7 (2022);
5-Year Impact Factor:
2.6 (2022)
Latest Articles
Combustion-Induced Endothermic Process in Carbon Dots Synthesized on Magnetite Nanoparticle Substrate
Crystals 2024, 14(6), 520; https://doi.org/10.3390/cryst14060520 (registering DOI) - 30 May 2024
Abstract
Carbon dots are synthesized alone and in the presence of commercial magnetite nanoparticles using a simple hydrothermal reaction. The spectroscopic and structural characteristics of CDot and CDot–magnetite materials are presented and their behaviors under combustion conditions are studied. A careful examination of their
[...] Read more.
Carbon dots are synthesized alone and in the presence of commercial magnetite nanoparticles using a simple hydrothermal reaction. The spectroscopic and structural characteristics of CDot and CDot–magnetite materials are presented and their behaviors under combustion conditions are studied. A careful examination of their combustion behaviors reveals interesting results for the CDot–magnetite material: it undergoes early catalytic combustion at ~200 °C and a strong endothermic process that quenches combustion. By investigating the physical mixtures of pre-formed CDots and magnetite and the starting material ascorbic acid and magnetite, it is determined that the strong endothermic behavior requires intimate interactions between the carbon source and the magnetite, highlighting the importance of the nano-interface of the CDots being synthesized onto the magnetite substrate. The results are discussed in the context of the fuels used for low-temper combustion, materials with stored endothermic potential, and the use of combustion-quenching materials for fire control.
Full article
(This article belongs to the Special Issue Synthesis and Application of Nanocomposite Materials)
►
Show Figures
Open AccessArticle
Tailoring the Magnetic and Hyperthermic Properties of Biphase Iron Oxide Nanocubes through Post-Annealing
by
Supun B. Attanayake, Amit Chanda, Raja Das, Manh-Huong Phan and Hariharan Srikanth
Crystals 2024, 14(6), 519; https://doi.org/10.3390/cryst14060519 (registering DOI) - 30 May 2024
Abstract
Tailoring the magnetic properties of iron oxide nanosystems is essential to expanding their biomedical applications. In this study, 34 nm iron oxide nanocubes with two phases consisting of Fe3O4 and α-Fe2O3 were annealed for 2 h in
[...] Read more.
Tailoring the magnetic properties of iron oxide nanosystems is essential to expanding their biomedical applications. In this study, 34 nm iron oxide nanocubes with two phases consisting of Fe3O4 and α-Fe2O3 were annealed for 2 h in the presence of O2, N2, He, and Ar to tune the respective phase volume fractions and control their magnetic properties. X-ray diffraction and magnetic measurements were carried out post-treatment to evaluate changes in the treated samples compared to the as-prepared samples, showing an enhancement of the α-Fe2O3 phase in the samples annealed with O2 while the others indicated a Fe3O4 enhancement. Furthermore, the latter samples indicated enhancements in crystallinity and saturation magnetization, while coercivity enhancements were the most significant in samples annealed with O2, resulting in the highest specific absorption rates (of up to 1000 W/g) in all the applied fields of 800, 600, and 400 Oe in agar during magnetic hyperthermia measurements. The general enhancement of the specific absorption rate post-annealing underscores the importance of the annealing atmosphere in the enhancement of the magnetic and structural properties of nanostructures.
Full article
(This article belongs to the Section Hybrid and Composite Crystalline Materials)
►▼
Show Figures
Figure 1
Open AccessArticle
Highly Efficient Terahertz Waveguide Using Two-Dimensional Tellurium Photonic Crystals with Complete Photonic Bandgaps
by
Yong Wang, Luyao Feng, Hongwei Huang, Zhifeng Zeng, Yuhan Liu, Xiaotong Liu, Xingquan Li, Kaiming Yang, Zhijian Zheng, Biaogang Xu, Wenlong He, Shaobin Zhan and Wenli Wang
Crystals 2024, 14(6), 518; https://doi.org/10.3390/cryst14060518 (registering DOI) - 29 May 2024
Abstract
A novel, highly efficient terahertz fully polarized transmission line is designed by two-dimensional tellurium photonic crystals consisting of square lattice rod arrays with a complete photonic bandgap. The TE and TM photonic bandgaps of the tellurium photonic crystals, which are computed by plane
[...] Read more.
A novel, highly efficient terahertz fully polarized transmission line is designed by two-dimensional tellurium photonic crystals consisting of square lattice rod arrays with a complete photonic bandgap. The TE and TM photonic bandgaps of the tellurium photonic crystals, which are computed by plane wave expansion, happen to coincide, and the complete photonic bandgap covers from 2.894 to 3.025 THz. The function of the designed waveguide is simulated by the finite element method, and the transmission characteristics are optimized by accurately adjusting its structural parameters. The transmission efficiency of the waveguide for TE mode achieves a peak value of −0.34 dB at a central frequency of 2.950 THz and keeps above −3 dB from 2.82 THz to 3.02 THz, obtaining a broad relative bandwidth of about 6.84 percent. The operating bandwidth of the tellurium photonic crystals’ waveguide for TM mode is narrower than that of TE mode, whose relative bandwidth is about 4.39 percent or around 2.936 THz above −5 dB. The designed terahertz photonic crystals’ waveguide can transmit both TE and TM waves, and not only can it be used as a high-efficiency transmission line, but it also provides a promising approach for implementing fully polarized THz devices for future 6G communication systems.
Full article
(This article belongs to the Section Inorganic Crystalline Materials)
►▼
Show Figures
Figure 1
Open AccessArticle
Effect of Nonmagnetic Hf Addition on Magnetic Properties of Melt-Spun Misch Metal-Fe-B Ribbons
by
Mihaela Lostun, Marian Grigoraș, Luiza C. Budeanu, Tiberiu Roman, Gabriela Buema, Gabriel Ababei, George Stoian and Nicoleta Lupu
Crystals 2024, 14(6), 517; https://doi.org/10.3390/cryst14060517 (registering DOI) - 29 May 2024
Abstract
Misch Metal (MM)-Fe-B magnets are proposed to develop permanent magnets with a high performance/cost ratio and to balance the disproportionate use of rare earth (RE) resources. To improve the magnetic performance of (MM)-Fe-B ribbons precursors of magnets, the addition of non-magnetic hafnium (Hf)
[...] Read more.
Misch Metal (MM)-Fe-B magnets are proposed to develop permanent magnets with a high performance/cost ratio and to balance the disproportionate use of rare earth (RE) resources. To improve the magnetic performance of (MM)-Fe-B ribbons precursors of magnets, the addition of non-magnetic hafnium (Hf) was used. MM14Fe80−xHfxB6 (x = 0–3 at. %) ribbons were fabricated by melt-spinning technique at a wheel velocity of 35 m/s and were then annealed to obtain a nanocrystalline structure. The ribbons’ magnetic properties, morphology, and structure were investigated methodically. It was found that the coercivity, Hc, of the MM14Fe80−xHfxB6 (x = 0–3 at. %) as-spun ribbons increased significantly from 5.85 kOe to 9.25 kOe with an increase in the Hf content from 0 to 2 at. %, while the remanence decreased slightly for the whole 0–3 range at. % Hf. The grain size of the RE2Fe14B phase gradually decreased as the Hf addition content increased from 0 to 3 at. %. As a result, the best combination of magnetic properties, such as Hc = 9.25 kOe, Mr = 87 emu/g, and maximum energy product (BH)max = 9.75 MGOe, was obtained in the ribbons with 2 at. % Hf addition was annealed at an optimal temperature of 650 degrees Celsius for 20 min. This work can serve as a useful reference for the further development of a new permanent magnet based on MM and Hf elements and can provide a feasible way for the efficient use of rare earth resources.
Full article
(This article belongs to the Section Inorganic Crystalline Materials)
►▼
Show Figures
Figure 1
Open AccessArticle
Grain Refinement and Mechanical Enhancement of Titanium Matrix Composites with Nickel-Coated Graphene Nanoflakes: Influence of Particle-Size Mismatch
by
Jie Zhang, Byung-Won Min, Hai Gu, Guo-Qing Wu, Guo-Qing Dai and Zhong-Gang Sun
Crystals 2024, 14(6), 516; https://doi.org/10.3390/cryst14060516 (registering DOI) - 29 May 2024
Abstract
A novel type of titanium matrix composite (TMC) with a uniform network microstructure has been successfully fabricated by adjusting particle-size mismatch (Φ). This study can also improve the understanding of the effects of particle size on microstructure and mechanical properties, particularly in titanium
[...] Read more.
A novel type of titanium matrix composite (TMC) with a uniform network microstructure has been successfully fabricated by adjusting particle-size mismatch (Φ). This study can also improve the understanding of the effects of particle size on microstructure and mechanical properties, particularly in titanium matrix composites reinforced with graphite flakes (GNFs). Microstructural analysis reveals the absence of noticeable defects, and significant grain refinements have been realized. The experimental results indicate that the yield strength of the mismatched composite is improved by 24.75% compared to that of normal composites. The micro-hardness also exhibits a 10.3% increase. These enhancements can be attributed to the introduction of particle-size mismatch, the refinement of the microstructure, and the deflection of interface cracks. The presence of distorted GNF lattices in the interface micro-region of the composites primarily results from the appropriate sizing of different particles.
Full article
(This article belongs to the Section Crystalline Metals and Alloys)
►▼
Show Figures
Figure 1
Open AccessArticle
New fac-[Re(CO)3(OO)(L)] and [Re(CO)2(OO)(L)2] Complexes Bearing Two Natural Food Additives, Maltol and Kojic Acid, as OO Ligands
by
Angeliki Panagiotopoulou, Patricia Kyprianidou, Charalampos Tsoukalas, Vassilis Psycharis, Catherine P. Raptopoulou, Ioannis Pirmettis, Minas S. Papadopoulos and Maria Pelecanou
Crystals 2024, 14(6), 515; https://doi.org/10.3390/cryst14060515 - 29 May 2024
Abstract
The synthesis and structural characterization of new “2+1” mixed ligand fac-[Re(CO)3(OO)(L)] and Re(CO)2(OO)(L)2 complexes are reported herein. Maltol and kojic acid were chosen as bidentate OO ligands, while imidazole, isocyanocyclohexane or triphenylphosphine were selected as the monodentate
[...] Read more.
The synthesis and structural characterization of new “2+1” mixed ligand fac-[Re(CO)3(OO)(L)] and Re(CO)2(OO)(L)2 complexes are reported herein. Maltol and kojic acid were chosen as bidentate OO ligands, while imidazole, isocyanocyclohexane or triphenylphosphine were selected as the monodentate ligands. The synthesis of the rhenium complexes was based on the reaction of [NEt4]2[Re(CO)3Br3] with maltol and kojic acid to generate the intermediate aqua complex fac-[Re(CO)3(OO)(H2O)], followed by the replacement of the labile aqua ligand by the monodentate ligand. Structural characterization of all Re complexes was established by NMR and IR spectroscopies, as well as two of them by single-crystal X-ray crystallography, revealing distorted octahedral geometry around the Re center. In the crystal lattice, the complexes form supramolecular networks due to the development of intermolecular interactions of the N-H⋯O, C-H⋯O and C-H⋯π type.
Full article
(This article belongs to the Special Issue Coordination Complexes: Synthesis, Characterization and Application)
►▼
Show Figures
Figure 1
Open AccessArticle
High-Temperature (Cu,C)Ba2Ca3Cu4Oy Superconducting Films with Large Irreversible Fields Grown on SrLaAlO4 Substrates by Pulsed Laser Deposition
by
Yugang Li, Zhiyong Liu, Ping Zhu, Jinyu He and Chuanbing Cai
Crystals 2024, 14(6), 514; https://doi.org/10.3390/cryst14060514 - 28 May 2024
Abstract
(Cu,C)Ba2Ca3Cu4Oy is a nontoxic cuprate superconducting material with a superconducting transition temperature of about 116 K. Recently, it was found that bulk samples of this material synthesized under high pressure hold the highest irreversibility line among
[...] Read more.
(Cu,C)Ba2Ca3Cu4Oy is a nontoxic cuprate superconducting material with a superconducting transition temperature of about 116 K. Recently, it was found that bulk samples of this material synthesized under high pressure hold the highest irreversibility line among all the superconductors, which is very promising for its application in the liquid nitrogen temperature field. In this work, high-temperature (Cu,C)Ba2Ca3Cu4Oy superconducting films with large irreversible fields were prepared on SrLaAlO4(00l) substrates by pulsed laser deposition. The substrate temperature during deposition proved to be the most important parameter determining the morphology and critical temperature of the superconductors, with 680 °C considered to be the optimum temperature. X-ray diffraction (XRD) results showed that the (Cu,C)Ba2Ca3Cu4Oy films prepared under optimal conditions exhibited epitaxial growth with the a-axis perpendicular to the film surface and the b- and c-axes parallel to the substrate, with no evidence of any other orientation. In addition, resistivity measurements showed that the onset transition temperature (Tconset) was approximately 116 K, the zero-resistance critical temperature (Tc0) was around 53 K, and the irreversible field (Hirr) was about 9 T at 37 K for (Cu,C)Ba2Ca3Cu4Oy films under optimal temperature. This is the first example of the successful growth of superconducting (Cu,C)Ba2Ca3Cu4Oy films on SrLaAlO4(00l) substrates. This will facilitate high-performance applications of (Cu,C)Ba2Ca3Cu4Oy superconducting materials in the liquid nitrogen temperature field.
Full article
(This article belongs to the Special Issue Advances in Synthesis, Characterization, and Application of Thin Films)
►▼
Show Figures
Figure 1
Open AccessArticle
Effect of Cubic Crystal Morphology on Thermal Characteristics and Mechanical Sensitivity of PYX
by
Xi Luo, Qiong Wang, Hongni Liu, Wenjie Li, Ruixue Zheng and Weiqiang Pang
Crystals 2024, 14(6), 513; https://doi.org/10.3390/cryst14060513 - 28 May 2024
Abstract
To investigate the influence of the cubic crystal morphology on the thermal properties and sensitivity of 2,6-bis(picrylamino)-3,5-dinitropyridine (PYX), cubic PYX (CPYX) crystals were prepared using the antisolvent method. Scanning electron microscopy (SEM), laser particle size analysis, X-ray diffraction (XRD) and Fourier transform infrared
[...] Read more.
To investigate the influence of the cubic crystal morphology on the thermal properties and sensitivity of 2,6-bis(picrylamino)-3,5-dinitropyridine (PYX), cubic PYX (CPYX) crystals were prepared using the antisolvent method. Scanning electron microscopy (SEM), laser particle size analysis, X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR) were used to characterize the morphology, particle size and structure of the prepared products. The thermal behavior, thermal decomposition kinetics, thermal safety parameters and thermal decomposition mechanism of CPYX were investigated by differential scanning calorimetry–thermogravimetry–mass spectrometry–Fourier transform infrared spectrometry (DSC-TG-MS-FT-IR) and in situ FT-IR experiments. Meanwhile, the mechanical sensitivity of CPYX was determined by means of the explosion probability method. The results showed that the product had a smooth cubic morphology and small crystal aspect ratio with an average particle size (d50) of 10.65 μm, but it had no distinct differences from the crystal structure of raw PYX (RPYX). The thermal decomposition peak temperature, the self-accelerating decomposition temperature and the critical temperature of the thermal explosion of CPYX increased by 7.2 °C, 6.1 °C and 10.4 °C, respectively, compared to RPYX. Similarly, the apparent activation energy increased by 15%. Besides these, the impact sensitivity and friction sensitivity of CPYX decreased by 36% and 20%, respectively, compared to RPYX. The decomposition process of CPYX contains two stages. The first stage involves the breakage of N-H bonds and -NO2 groups with the release of CO2, N2O, NO, HCN and H2O, followed by the thermal decomposition of the resulting intermediate and the release of CO2, N2O and HCN in the second stage.
Full article
(This article belongs to the Section Materials for Energy Applications)
►▼
Show Figures
Figure 1
Open AccessReview
Photonic Devices with Multi-Domain Liquid Crystal Structures
by
Aleksey Kudreyko, Vladimir Chigrinov, Kristiaan Neyts, Denis Chausov and Arina Perestoronina
Crystals 2024, 14(6), 512; https://doi.org/10.3390/cryst14060512 - 28 May 2024
Abstract
Photoalignment by azo dye nanolayers can provide high alignment quality for large-area liquid crystal devices. Application of this technology to active optical elements for signal processing and communications is a hot topic of photonics research. In this article, we review recent demonstrations and
[...] Read more.
Photoalignment by azo dye nanolayers can provide high alignment quality for large-area liquid crystal devices. Application of this technology to active optical elements for signal processing and communications is a hot topic of photonics research. In this article, we review recent demonstrations and performance of liquid crystal photonic devices, discuss the advantages of the proposed technology, and identify challenges and future prospects in the research field of photoaligned multi-domain liquid crystal structures. We believe that the developments discussed here can provide directions for future research and potential opportunities for applications of liquid crystal devices based on multi-domain photoalignment.
Full article
(This article belongs to the Special Issue Optical Crystals and Their Applications in Optical Devices)
Open AccessArticle
Influence of Stress on the Chiral Polarization and Elastrocaloric Effect in BaTiO3 with 180° Domain Structure
by
Yuanyuan Shi and Bo Li
Crystals 2024, 14(6), 511; https://doi.org/10.3390/cryst14060511 - 28 May 2024
Abstract
The polarization and elastrocaloric effect of chiral barium titanate (BaTiO3) with an Ising–Bloch-type domain wall under stress was investigated using the Landau–Ginzburg–Devonshire (LGD) theory. It has been shown that tensile stresses increase the magnitude of the Ising polarization component in barium
[...] Read more.
The polarization and elastrocaloric effect of chiral barium titanate (BaTiO3) with an Ising–Bloch-type domain wall under stress was investigated using the Landau–Ginzburg–Devonshire (LGD) theory. It has been shown that tensile stresses increase the magnitude of the Ising polarization component in barium titanate, together with a decrease in the domain wall width. Compressive stresses cause a reduction in the Ising polarization component and an increase in the domain width. Under compressive stress, barium titanate exhibits a negative elastrocaloric effect and temperature changes with increasing stress, while BaTiO3 exhibits a positive elastrocaloric effect under tensile stress. Bloch polarization shows angle-dependent polarization under external force, but the temperature change from the elastrocaloric effect is smaller than that of Ising polarization under stress. This work contributes to the understanding of polarization evolution under tension in ferroelectrics with chiral structure.
Full article
(This article belongs to the Special Issue Emerging Applications of Ferroelectrics in Nanoelectronics and Renewable Energy)
►▼
Show Figures
Figure 1
Open AccessArticle
Syzygium aromaticum Bud Extracted Core–Shell Ag–Fe Bimetallic Nanoparticles: Phytotoxic, Antioxidant, Insecticidal, and Antibacterial Properties
by
Farah Murtaza, Naseem Akhter, Muhammad Azam Qamar, Asma Yaqoob, Anis Ahmad Chaudhary, Bhagyashree R. Patil, Salah Ud-Din Khan, Nasir Adam Ibrahim, Nosiba S. Basher, Mohammed Saad Aleissa, Iqra Kanwal and Mohd Imran
Crystals 2024, 14(6), 510; https://doi.org/10.3390/cryst14060510 - 27 May 2024
Abstract
Today, there is the roar of sustainable material development around the globe. Green nanotechnology is one of the extensions of sustainability. Due to its sustainable approach, the green fabrication of nanoparticles has recently surpassed their classical synthesis in popularity. Among metal nanoparticles, contemporary
[...] Read more.
Today, there is the roar of sustainable material development around the globe. Green nanotechnology is one of the extensions of sustainability. Due to its sustainable approach, the green fabrication of nanoparticles has recently surpassed their classical synthesis in popularity. Among metal nanoparticles, contemporary findings have demonstrated that bimetallic nanoparticles possess more potential for different applications than monometallic nanoparticles due to the synergistic effects of the two metals. So, we are presenting facile, one-vessel, and one-step phyto-fabrication of Ag–Fe BMNPs using the bud extract of Syzygiumaromaticum. The synthesized nanoparticles were characterized by UV-VIS, XRD, EDX, FTIR, and SEM. The synthesized NPs and the extract underwent biological studies. The radical scavenging potential of the NPs and the extract was found to be 64% and 73%, and the insecticidal potential was found to be 80% and 100%, respectively. Similarly, the NPs and the extract both exhibited good antibacterial activity. The zone of inhibition using 100 mg/mL of extract and NPs was found to be 1 cm against all bacterial species, i.e., K. pneumonia, E. coli, and S. aureus. It was 1.5 cm, 1.3 cm, and 1 cm against K. pneumonia, E. coli, and S. aureus, respectively, showing that the antibacterial activity of the extract is higher than that of the NPs. So, this study unlocks the synthesis of Ag–Fe bimetallic nanoparticles using eco-safe, cost-effective, facile, and least-harmful green methodology with potential applications of both NPs and SA extract in medical and agricultural fields, a step towards sustainability.
Full article
(This article belongs to the Special Issue Metal Oxide Thin Films, Nanomaterials and Nanostructures)
►▼
Show Figures
Figure 1
Open AccessArticle
Preparation, Characterization, and High-Temperature Anti-Seizing Application of CrAlN-Based Gradient Multilayer Coatings
by
Chunmei Tang, Dingjun Li, Xiaohu Yuan, Wei Wang, Xianping Guo, Yu Fang, Xiufang Gong and Quande Li
Crystals 2024, 14(6), 509; https://doi.org/10.3390/cryst14060509 - 27 May 2024
Abstract
High-temperature fasteners are metal parts of gas turbines and steam turbines, which work at high temperatures and under stress for a long time. However, the frequent seizures of fasteners bring great trouble to the normal maintenance of power plants. In this paper, three
[...] Read more.
High-temperature fasteners are metal parts of gas turbines and steam turbines, which work at high temperatures and under stress for a long time. However, the frequent seizures of fasteners bring great trouble to the normal maintenance of power plants. In this paper, three kinds of dense and controllable CrAlN-based gradient multilayer coatings were prepared on the samples and screws by arc ion plating (AIP) technology. The morphology, composition, structure, nano hardness, adhesion, residual stress, and room temperature tribological performance of the coating were investigated. To evaluate the high-temperature, anti-seizing performance, coated screws were heated to 700 °C for 140 h with a torque of 20 N·m. The results indicate that the CrN/CrAlN multilayer coating shows better comprehensive properties. The characterization of coated screws proved that the coating structures obtained on the screws were similar to the flat samples. However, the as-prepared coating on the screws showed different thickness variation rules, which was related to the clamping method, deposition distance, and screw shape. After a simulation service, the thread of the screw remained intact with similar structure and thinner thickness. The above results indicate that the high-temperature seize prevention of fasteners can be successfully achieved by preparing a CrAlN-based multilayer coating, which is suitable for fasteners with service temperatures below 700 °C.
Full article
(This article belongs to the Special Issue Advanced Surface Modifications on Materials)
►▼
Show Figures
Figure 1
Open AccessArticle
Efficient Adsorption Removal of Tetrabromobisphenol A from Water by Using a Magnetic Composite Fe3O4/GO/ZIF-67
by
Sumei Li, Jian Ji, Saisai Shan, Sha Chen, Hanbing Li, Qian Xu and Yixuan Liang
Crystals 2024, 14(6), 508; https://doi.org/10.3390/cryst14060508 - 27 May 2024
Abstract
Tetrabromobisphenol A (TBBPA) is a kind of widely used brominated flame retardant (BFR), which is proven to be harmful to ecological systems and public health. It is very important to remove TBBPA from the environment. In our study, a magnetic composite named Fe
[...] Read more.
Tetrabromobisphenol A (TBBPA) is a kind of widely used brominated flame retardant (BFR), which is proven to be harmful to ecological systems and public health. It is very important to remove TBBPA from the environment. In our study, a magnetic composite named Fe3O4/GO/ZIF-67 was synthesized by a coprecipitation method and applied in the highly efficient adsorption of TBBPA from water. Static adsorption experiments demonstrated that the adsorption capacity could reach 232 mg·g−1 within 120 min, which is much higher than those reported in the other literature. The experimental results show that the adsorption of TBBPA on Fe3O4/GO/ZIF-67 followed Langmuir and pseudo-second-order kinetic adsorption models. The main mechanisms for these adsorptions were identified as hydrogen bonds between OH groups in TBBPA and COOHs of Fe3O4/GO/ZIF-67, and π-π stacking between Fe3O4/GO/ZIF-67 and TBBPA. This study provides a method with great promise for the design and synthesis of better adsorbents for the removal of TBBPA from the water environment.
Full article
(This article belongs to the Special Issue Recent Advances in Metal-Organic Frameworks: Synthesis, Characterization and Application)
►▼
Show Figures
Figure 1
Open AccessArticle
First-Principles Study of Ti-Doping Effects on Hard Magnetic Properties of RFe11Ti Magnets
by
Chengyuan Xu, Lin Wen, Anjian Pan, Lizhong Zhao, Yuansen Liu, Xuefeng Liao, Yu Pan and Xuefeng Zhang
Crystals 2024, 14(6), 507; https://doi.org/10.3390/cryst14060507 - 27 May 2024
Abstract
Due to the rare earth supply shortage, ThMn12-type RFe12-based (R is the rare earth element) magnets with lean rare earth content are gaining more concern. Most ThMn12-type RFe12 structures are thermodynamically metastable and require doping of
[...] Read more.
Due to the rare earth supply shortage, ThMn12-type RFe12-based (R is the rare earth element) magnets with lean rare earth content are gaining more concern. Most ThMn12-type RFe12 structures are thermodynamically metastable and require doping of the stabilizing element Ti. However, the Ti-doping effects on the hard magnetic properties of RFe11Ti have not been thoroughly investigated. Herein, based on density functional theory calculations, we report the Ti-doping effects on the phase stability, intrinsic hard magnetic properties and electronic structures of RFe11Ti (R = La, Ce, Pr, Nd, Sm, Y, Zr). Our results indicate that Ti-doping not only increases their phase stability, but also enhances the magnetic hardness of ground-state RFe12 phases. Particularly, it leads to the transition of CeFe11Ti and PrFe11Ti from easy-plane to easy-axis anisotropy. Charge density distributions demonstrate that Ti-doping breaks the original symmetry of the R-site crystal field, which alters the magnetic anisotropy of RFe11Ti. Projected densities of states reveal that the addition of Ti results in the shift of occupied and unoccupied f-electron energy levels of rare earth elements, affecting their magnetic exchange. This study provides an insight into regulating the hard magnetic properties of RFe12-based magnets by Ti-doping.
Full article
(This article belongs to the Special Issue The Synthesis and Prospects of Magnetic Materials)
►▼
Show Figures
Figure 1
Open AccessArticle
Multicomponent Nanoparticles Decorating a Lignin-Derived Biochar Composite for 2-Nitrophenol Sensing
by
Tianshuang Bao, Qi Wang, Yuhang Jiang, Xiangchuan Zhao, Yue Cao, Jun Cao, Qiaoling Li and Weimeng Si
Crystals 2024, 14(6), 506; https://doi.org/10.3390/cryst14060506 - 27 May 2024
Abstract
Lignin, which contains aromatic phenols, is the second most abundant renewable biomass material in the world. It is the main byproduct of the paper industry and is characterized by abundant sources, renewability, and low cost. The present study focused on the extraction of
[...] Read more.
Lignin, which contains aromatic phenols, is the second most abundant renewable biomass material in the world. It is the main byproduct of the paper industry and is characterized by abundant sources, renewability, and low cost. The present study focused on the extraction of lignin from poplar wood through a straightforward papermaking approach, thereafter utilizing the resultant black liquor containing lignin for synthesizing lignin-based phenolic resins. During the polymerization process, cobalt (Co) and nickel (Ni) species were introduced and, subsequently, a CoNi/biochar catalyst was obtained through pyrolysis in a nitrogen atmosphere. The prepared catalyst possessed rough spherical structures. The incorporation of Co and Ni enhanced charge redistribution, thereby imparting the catalyst with strong electron acceptance capabilities. The prepared lignin-based phenolic-resin-derived carbon was used for the electrochemical sensing of 2-nitrophenol. The limit of detection (LOD) for 2-nitrophenol was calculated to be 0.0132 µM, with good repeatability, stability, and selectivity.
Full article
(This article belongs to the Section Hybrid and Composite Crystalline Materials)
►▼
Show Figures
Figure 1
Open AccessArticle
Oxidized Graphite Nanocrystals for White Light Emission
by
Patrik Ščajev, Saulius Miasojedovas, Algirdas Mekys, Gediminas Kreiza, Justinas Čeponkus, Valdas Šablinskas, Tadas Malinauskas and Arturs Medvids
Crystals 2024, 14(6), 505; https://doi.org/10.3390/cryst14060505 - 25 May 2024
Abstract
We investigated the formation of graphite nanocrystals covered with graphite oxide for white light generation. The nanoparticles were formed using cost-efficient oxidation of a carbon-based dye pigment at different temperatures and verified using X-ray diffraction and Raman measurements. Formation of the graphite nanoparticles
[...] Read more.
We investigated the formation of graphite nanocrystals covered with graphite oxide for white light generation. The nanoparticles were formed using cost-efficient oxidation of a carbon-based dye pigment at different temperatures and verified using X-ray diffraction and Raman measurements. Formation of the graphite nanoparticles via thermal annealing was observed, while their light emission increased at higher oxidation temperatures. This was associated with a higher amount of oxygen defect groups. The time-resolved photoluminescence measurements showed linearly faster decays at shorter wavelengths and similar decays at different annealing temperatures. Broadband and linear vs. excitation emission spectra of the particles were found to be suitable for white-light-emitting devices and phosphor markers. The fast photoluminescence decay opens the possibility for the application of nanoparticles in optical wireless communication technology.
Full article
(This article belongs to the Special Issue Semiconductor Nanocrystal Studies for Optoelectronic Applications)
►▼
Show Figures
Figure 1
Open AccessArticle
Dissociative Adsorption of O2 on Ag3Au(111) Surface: A Density Functional Theory Study
by
Yanlin Yu, Mingan Fu, Huaizhang Gu, Lei Wang, Wanxiu Liu, Qian Xie and Guojiang Wu
Crystals 2024, 14(6), 504; https://doi.org/10.3390/cryst14060504 - 25 May 2024
Abstract
The catalytic efficiency of oxygen reduction catalysts is notably influenced by the dissociative adsorption of O2. We conducted a systematic investigation into the dissociative adsorption of O2 on the Ag3Au(111) surface using ab initio density functional theory (DFT)
[...] Read more.
The catalytic efficiency of oxygen reduction catalysts is notably influenced by the dissociative adsorption of O2. We conducted a systematic investigation into the dissociative adsorption of O2 on the Ag3Au(111) surface using ab initio density functional theory (DFT) calculations. Our computational findings indicate that adsorption the configuration designated t-b-t exhibits favorable energetics on the Ag3Au(111) surface. Regarding the dissociation of O2, we identified a reasonable dissociation pathway, which proceeds from the initial t-b-t state to the creation of two oxygen atoms that occupy a set of neighboring fcc sites. Furthermore, our analysis indicates that the adsorption of O2 on the Ag3Au(111) surface is less favored thermodynamically and more difficult to dissociate than that on the Ag(111) surface. This study furnishes a theoretical framework elucidating the prospective utilization of Ag-Au alloy in the capacity of oxygen reduction catalysts.
Full article
(This article belongs to the Section Materials for Energy Applications)
►▼
Show Figures
Figure 1
Open AccessArticle
High-Efficiency Vertical-Chip Micro-Light-Emitting Diodes via p-GaN Optimization and Surface Passivation
by
Yizhou Qian, En-Lin Hsiang, Yu-Hsin Huang, Kuan-Heng Lin and Shin-Tson Wu
Crystals 2024, 14(6), 503; https://doi.org/10.3390/cryst14060503 - 25 May 2024
Abstract
Micro-LEDs have found widespread applications in modular large-screen TVs, automotive displays, and high-resolution-density augmented reality glasses. However, these micron-sized LEDs experience a significant efficiency reduction due to the defects originating from the dry etching process. By controlling the current distribution via engineering the
[...] Read more.
Micro-LEDs have found widespread applications in modular large-screen TVs, automotive displays, and high-resolution-density augmented reality glasses. However, these micron-sized LEDs experience a significant efficiency reduction due to the defects originating from the dry etching process. By controlling the current distribution via engineering the electrode size, electrons will be less concentrated in the defect region. In this work, we propose a blue InGaN/GaN compound parabolic concentrator micro-LED with a metallic sidewall to boost efficiency by combining both an optical dipole cloud model and electrical TCAD (Technology Computer-Aided Design) model. By merely modifying the p-GaN contact size, the external quantum efficiency (EQE) can be improved by 15.6%. By further optimizing the passivation layer thickness, the EQE can be boosted by 52.1%, which helps enhance the display brightness or lower power consumption.
Full article
(This article belongs to the Section Organic Crystalline Materials)
►▼
Show Figures
Figure 1
Open AccessArticle
Thermal Characterization of [C2Im][NO3] and Multivalent Nitrate Salts Mixtures
by
Pablo Vallet, Juan José Parajó, Antía Santiago-Alonso, María Villanueva, Luis Miguel Varela and Josefa Salgado
Crystals 2024, 14(6), 502; https://doi.org/10.3390/cryst14060502 - 25 May 2024
Abstract
Due to their intrinsic properties, the current applicability of ionic liquids is enormous. In particular, their use in electrochemistry is beyond question. Numerous studies on these compounds and their mixtures, especially with lithium salts, focus on their use as electrolytes for batteries and
[...] Read more.
Due to their intrinsic properties, the current applicability of ionic liquids is enormous. In particular, their use in electrochemistry is beyond question. Numerous studies on these compounds and their mixtures, especially with lithium salts, focus on their use as electrolytes for batteries and other energy storage devices. This includes thermal energy storage devices, where 4th generation ionic liquids and their derivatives show a huge potential. Nevertheless, considering the uneven availability of the raw materials, such as lithium, research has extended to mixtures of these compounds with other salts of different metals that are more abundant and widely distributed, such as magnesium or aluminum. This work presents a comprehensive thermal characterization, using differential scanning calorimetry and thermogravimetry, of the protic ionic liquid ethylimidazolium nitrate and its mixture with magnesium and aluminum nitrate salts at different concentrations. Additionally, a comparison between these results and previous studies of mixtures of this ionic liquid with lithium nitrate, as well as mixtures of the protic ionic liquid EAN with the same metal salts, was also performed. The results indicated that the salt addition tends to broaden and reduce crystallization and melting peaks, while the glass transition becomes more visible and shifts to higher temperatures with increasing salt concentration. This is due to the disorder generated by the rearrangement of ions in the polar domains, which erodes the hydrogen bond network of the protic ionic liquid. Nevertheless, the thermal stability of the blended samples does not change significantly compared to the bulk ionic liquid.
Full article
(This article belongs to the Section Materials for Energy Applications)
►▼
Show Figures
Figure 1
Open AccessReview
Machine Learning Methods to Improve Crystallization through the Prediction of Solute–Solvent Interactions
by
Aatish Kandaswamy and Sebastian P. Schwaminger
Crystals 2024, 14(6), 501; https://doi.org/10.3390/cryst14060501 - 24 May 2024
Abstract
Crystallization plays a crucial role in defining the quality and functionality of products across various industries, including pharmaceutical, food and beverage, and chemical manufacturing. The process’s efficiency and outcome are significantly influenced by solute–solvent interactions, which determine the crystalline product’s purity, size, and
[...] Read more.
Crystallization plays a crucial role in defining the quality and functionality of products across various industries, including pharmaceutical, food and beverage, and chemical manufacturing. The process’s efficiency and outcome are significantly influenced by solute–solvent interactions, which determine the crystalline product’s purity, size, and morphology. These attributes, in turn, impact the product’s efficacy, safety, and consumer acceptance. Traditional methods of optimizing crystallization conditions are often empirical, time-consuming, and less adaptable to complex chemical systems. This research addresses these challenges by leveraging machine learning techniques to predict and optimize solute–solvent interactions, thereby enhancing crystallization outcomes. This review provides a novel approach to understanding and controlling crystallization processes by integrating supervised, unsupervised, and reinforcement learning models. Machine learning not only improves product the quality and manufacturing efficiency but also contributes to more sustainable industrial practices by minimizing waste and energy consumption.
Full article
(This article belongs to the Section Biomolecular Crystals)
►▼
Show Figures
Figure 1
Journal Menu
► ▼ Journal Menu-
- Crystals Home
- Aims & Scope
- Editorial Board
- Reviewer Board
- Topical Advisory Panel
- Instructions for Authors
- Special Issues
- Topics
- Sections & Collections
- Article Processing Charge
- Indexing & Archiving
- Editor’s Choice Articles
- Most Cited & Viewed
- Journal Statistics
- Journal History
- Journal Awards
- Society Collaborations
- Conferences
- Editorial Office
Journal Browser
► ▼ Journal BrowserHighly Accessed Articles
Latest Books
E-Mail Alert
News
Topics
Topic in
Applied Sciences, Crystals, J. Compos. Sci., Materials, Metals
Modern Material Technologies Intended for Industrial Applications
Topic Editors: Tomasz Tański, Andrzej N. Wieczorek, Marcin StaszukDeadline: 30 June 2024
Topic in
Catalysts, Coatings, Crystals, Energies, Materials, Nanomaterials
Interfacial Bonding Design and Applications in Structural and Functional Materials
Topic Editors: Junlei Qi, Pengcheng Wang, Yaotian YanDeadline: 20 July 2024
Topic in
Crystals, Mathematics, Symmetry, Fractal Fract, Axioms
Mathematical Applications of Nonlinear Wave Properties in Crystalline and Dispersive Media
Topic Editors: Mahmoud A.E. Abdelrahman, Emad El-ShewyDeadline: 31 August 2024
Topic in
Acoustics, Crystals, Designs, Environments, Sustainability
Towards Sustainable and Liveable Cities: Recent Advances in Noise Control Measures
Topic Editors: Heow Pueh Lee, Linus Yinn Leng AngDeadline: 30 September 2024
Conferences
Special Issues
Special Issue in
Crystals
Wide Bandgap Semiconductor: GaN and SiC Material and Device
Guest Editors: Hao-chung Kuo, Chun-Hsiung Lin, Kung-Yen LeeDeadline: 30 May 2024
Special Issue in
Crystals
Advances in Low-Dimensional Materials for Electronics and Sensing Applications
Guest Editors: Hu Li, Klaus LeiferDeadline: 20 June 2024
Special Issue in
Crystals
Nucleic Acid Crystallography Volume II
Guest Editor: Blaine MooersDeadline: 25 June 2024
Special Issue in
Crystals
Structural Studies in Drug Discovery and Development: From the Lead to the Pharmaceutical Form
Guest Editors: Fiorella Meneghetti, Matteo MoriDeadline: 20 July 2024
Topical Collections
Topical Collection in
Crystals
Research on REBCO Films and Conductors
Collection Editors: Jens Hänisch, Hannes Rijckaert, Pablo Cayado