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A novel Cr-doped BaTiO3 aerogel was successfully synthesized using a co-gelation technique that involves two metallic alkoxides and a supercritical drying method. This freshly prepared aerogel has a high specific surface area of over 100 m2/g and exhibits improved responsiveness to the simulated sunlight spectrum. Methyl orange (MO) was chosen as the simulated pollutant, and the results reveal that the Cr-doped BaTiO3 aerogel, when modified with the noble metal silver (Ag), achieves a pollutant removal rate approximately 3.2 times higher than that of the commercially available P25, reaching up to 92% within 60 min. The excellent photocatalytic performance of the Ag-modified Cr-doped BaTiO3 aerogel can be primarily attributed to its extensive specific surface area and three-dimensional porous architecture. Furthermore, the incorporation of Ag nanoparticles effectively suppresses the recombination of photo-generated electrons and holes. Stability and reusability tests have confirmed the reliability of the Ag-modified Cr-doped BaTiO3 aerogel. Therefore, this material emerges as a highly promising candidate for the treatment of textile wastewater. [ABSTRACT FROM AUTHOR]

The degradation of amoxicillin residue has been performed using TiO2 photocatalyst doped with Cr prepared from tannery wastewater under visible light exposure. The incorporation of Cr metal into TiO2 structure was conducted via hydrothermal method. From the characterization results, it is found that doping Cr from the tannery wastewater into TiO2 structure has been successfully shifted the light absorption into visible region. Among the various Cr content in the TiO2-Cr photocatalyst, TiO2-0.33Cr (medium level) shows the highest ability in the visible light absorption, suggesting it to be the best photocatalyst. It is also clearly proven that in the presence of TiO2-0.33Cr photocatalyst, the degradation of amoxicillin can reach almost 100 % after the third cycles. Furthermore, this study also investigated the optimum condition for photodegradation of amoxicillin as the prevalent antibiotic residue in batch technique. The concentration of amoxicillin after the photodegradation process was determined using a UV–visible spectrophotometer. The result identifies the optimal condition for the amoxicillin photodegradation is reached at pH 6, with 10 mg of the photocatalyst mass per 30 mL of the sample solution, and an irradiation time at 90 min. The photodegradation of amoxicillin using TiO2-0.33Cr follows the pseudo-first order kinetic model with kinetic constant (k) is high as 0.004 min−1.

A novel Cr-doped BaTiO3 aerogel was successfully synthesized using a co-gelation technique that involves two metallic alkoxides and a supercritical drying method. This freshly prepared aerogel has a high specific surface area of over 100 m2/g and exhibits improved responsiveness to the simulated sunlight spectrum. Methyl orange (MO) was chosen as the simulated pollutant, and the results reveal that the Cr-doped BaTiO3 aerogel, when modified with the noble metal silver (Ag), achieves a pollutant removal rate approximately 3.2 times higher than that of the commercially available P25, reaching up to 92% within 60 min. The excellent photocatalytic performance of the Ag-modified Cr-doped BaTiO3 aerogel can be primarily attributed to its extensive specific surface area and three-dimensional porous architecture. Furthermore, the incorporation of Ag nanoparticles effectively suppresses the recombination of photo-generated electrons and holes. Stability and reusability tests have confirmed the reliability of the Ag-modified Cr-doped BaTiO3 aerogel. Therefore, this material emerges as a highly promising candidate for the treatment of textile wastewater.

Copyright of Inorganic Chemicals Industry is the property of Editorial Office of Inorganic Chemicals Industry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The structure, elastic properties and electronic structure of Ti-Al intermetallics including Ti3Al (space group P63/mmc), TiAl (space group I4/mmm) and TiAl3 (space group P4/mmm) are systematically studied by first-principles calculations. The results show that Ti-Al intermetallics can exist stably whether Cr replaces Ti or Al. The ductility of the alloy cannot be improved when Ti is replaced in Cr-doped TiAl and TiAl3. However, when it replaces Al, the alloy has better ductility. In Ti3Al, the ductility can be improved regardless of whether Cr replaces Ti or Al, and the effect is better when it replaces Al. The bond in Ti-Al intermetallics is mainly a Ti-Ti metal bond. The metal bond between Ti-Ti is strengthened and a solid metal bond is formed between Cr and Ti, inducing a better ductility of the material, after Cr replaces Al in Ti-Al intermetallics. [ABSTRACT FROM AUTHOR]

In this study, we used first-principles calculation methods to investigate the effects of Cr doping at different positions on the electronic and optical properties of ZnSe nanowires. We found that the bandgap of the nanowires is larger than that of the bulk. After doping, it was found that the easiest doping position is on the surface, while all positions require heating for doping. After doping, the change in the intrinsic bandgap was very small, and a large number of defect bands appeared in the middle of the intrinsic bandgap, which are mainly composed of Cr(d) orbital electrons, Se(p) orbital electrons, and d-p hybridized bands. The doping of Cr atoms also affects the distribution of LUMO and HOMO. In the parallel direction of the nanowires, the absorption spectrum exhibits a prominent absorption peak near 0.8 eV, which is caused by transitions between defect bands. Therefore, Cr-doped ZnSe (111) nanowires doped at radius ½ positions are more suitable as mid-infrared laser gain materials.

The structure, elastic properties and electronic structure of Ti-Al intermetallics including Ti3Al (space group P63/mmc), TiAl (space group I4/mmm) and TiAl3 (space group P4/mmm) are systematically studied by first-principles calculations. The results show that Ti-Al intermetallics can exist stably whether Cr replaces Ti or Al. The ductility of the alloy cannot be improved when Ti is replaced in Cr-doped TiAl and TiAl3. However, when it replaces Al, the alloy has better ductility. In Ti3Al, the ductility can be improved regardless of whether Cr replaces Ti or Al, and the effect is better when it replaces Al. The bond in Ti-Al intermetallics is mainly a Ti-Ti metal bond. The metal bond between Ti-Ti is strengthened and a solid metal bond is formed between Cr and Ti, inducing a better ductility of the material, after Cr replaces Al in Ti-Al intermetallics.

The present work focused on the synthesis and characterization of Cr (~2, 3 & 5 wt.%) doped Fe2O3 nanoparticles with desired electrochemical property for creatinine bio sensor applications via the extraction of Nyctanthes arbor tristis seed by facile chemical precipitation method. The synthesized samples have dimensions of the order of 0.5 to 0.8 µm and crystallite size of the prepared samples calculated by Powder XRD analysis using Scherer's formula. The optical characterization of the prepared nanomaterials showed that the band gap energy of the annealed chromium doped samples were found to be 5.74 eV by varying in intensity by Tauc plot that established well optical nature of the synthesized compound which is also have a good concord with the Powder XRD analysis with its crystalline nature. The FT-IR spectra clearly indicating the complete formation of Fe2O3 by observing corresponding functional groups such as Fe=O and O=O vibrations in their respective wavenumbers. The sensing performance of the prepared samples for creatinine was carried out using electrochemical workstation. Interestingly, the electrochemical analysis exposed the good sensing behaviour of the Cr-doped Fe2O3 nanoparticles which displayed corresponding redox peaks attributed to the reversible Faradaic redox reaction at the electrode surface caused by the pseudo-capacitance nature for a - Fe2O3 nanoparticles as an active material, slightly than the double layer capacitance. Consequently the current outcomes revealed a good sensing behaviour on creatinine for Cr-doped Fe2O3 nanoparticles synthesized by an effortless cost effective green synthesis method. [ABSTRACT FROM AUTHOR]

The series of Cr-substituted Co–Cu nanoferrite materials have been developed having the chemical compositions Co0.7Cu0.3Fe2-xCrxO4, x = 0.00, 0.05, 0.10, 0.15, 0.20, and 0.25. These ferrite materials are prepared by using the solgel auto combustion method. These materials are characterized by XRD, FESEM with EDS, HRTEM, FTIR, dc resistivity, and VSM studies. Chromium is found to occupy the B-sites replacing Fe3+ ions. The density of all the materials is found to increase except at higher values of Cr concentration. The lattice parameter of Cr-substituted ferrites is found to increase with the rise of Cr content. The dc resistivity is decreasing with an increase in temperature and thus reveals the materials' semiconductor nature. VSM study was utilized to characterize and estimate the magnetic features like magnetic saturation and the samples' coercivity. [ABSTRACT FROM AUTHOR]

Using sol-gel auto combustion technique complex ferrite nanoparticles have been synthesized. Characterization with the help of X-ray diffraction (XRD) revealed that the synthesized materials Cu0.7Co0.3Fe2−xCrxO4 are of a single-phase cubic spinel structure with Fd-3 m space group. And also, the samples’ crystallite sizes calculated using XRD data yielded in the range of 19.28–32.92 nm. The lattice constants are calculated to be between 8.4099 Å and 8.4441 Å. The FTIR results revealed that the spinel structure remained undisturbed even after the Cr ions were doped. FESEM images display the materials constitute polygonal-shaped grains though at times irregularly shaped gains with slight agglomeration appear. EDS analysis confirmed that the sample contained the constituent elements. A decreasing pattern in DC resistivity with an increase in temperature was observed, ensuring the semiconducting character of the ferrites under investigation. VSM was utilized to characterize and estimate the magnetic features like magnetic saturation and coercivity of the samples.

Carcinogenic hexavalent Cr in the current iron oxide-based catalysts of high temperature water-gas shift (HT-WGS) reaction is great environmental concern. Interpreting the role of the Cr in this important industrial catalyst system is required. In the present study, we investigated substitution of Cr atoms into the most stable termination of Fe 3 O 4 (111) slab surface by spin-polarized periodic DFT approach to comprehend the role of Cr. We applied the projector augmented-wave (PAW) method within the Perdew-Wang 1991 (PW91) form of the generalized gradient approximation (GGA) on the Vienna Ab-initio Simulation Package (VASP). The calculations point out that Cr atoms choose being below the surface FeO 6 sites. Cr slightly affects the dissociative H 2 O adsorption. There is no effect on the CO adsorption. Oxygen vacancy is favored to form on the topmost layer with less vacancy formation energy. Substitution of Cr into the structure increases the oxygen vacancy formation energy. This indicates that Cr does not act as a chemical promoter and does not affect the catalytic activity positively, which is experimentally confirmed by the previous studies. [Display omitted] • Surface FeO 6 is catalytic active site for HT-WGS reaction. • Oxygen atom from the topmost layer most energetically favorable for vacancy formation. • Cr modifies surface FeO 6 site by acting as ligand from below. • Cr increases energy for oxygen vacancy formation (increases E act). [ABSTRACT FROM AUTHOR]

According to the firs-principles theory-based spin-density functional calculations within the framework of Wu–Cohen generalized gradient approximation (WC-GGA), we examine the structural and electronic properties of ternary alloys of zinc-blende boron phosphide doped with chromium. We compare the materials with aluminum phosphide that exhibits half-metallic properties at various concentrations. The curves of total and partial densities of states and the band structures show that B 1 − x Cr x P are purely metallic and can be possible candidates for use in light emitting diodes (LEDs). These compounds are not polarized on spins; the main cause is the nature of chemical bond located between the boron cations and the phosphorus anion, whereas the ternary materials of Al 1 − x Cr x P all have various uses in spintronic science according to many studies because of their half-metallicity behavior. [ABSTRACT FROM AUTHOR]

Inorganic semiconducting ZnS doped with Cr nanoparticles was fabricated using chemical co-precipitation method with monothioethylene glycol as capping agent. This study is an effort to investigate as to how various concentration ratios of systematically doped Cr (1, 3, 5, and 7 wt%) to ZnS affect structural, optical, and morphological properties at room temperature. Powder X-ray diffraction (XRD) studies revealed that crystallinity improved upon doping and the synthesized material has cubic structure without secondary phase. XRD and Raman spectra showed successful incorporation of Cr3+ particles into ZnS host lattice. The functional groups and chemical species associated with vibration of molecules were determined with Fourier transform infrared spectroscopy (FTIR). Field-emission scanning electron microscope (FE-SEM) and high-resolution transmission electron microscope (HR-TEM) images showed nanoscale particles with cubic and spherical morphology. Elemental composition of Cr-ZnS particles was determined using energy-dispersive X-ray (EDX) spectroscopy. Kinetics of degradation of methylene blue (MB) catalyzed via synthesized nanoparticles was recorded under UV–Vis irradiation. The antimicrobial evaluation of Cr-doped ZnS nanocomposites against MDR S. aureus showed significant (p < 0.05) inhibition zones compared to undoped ZnS. The catalytic activity results indicate that ZnS is an efficient nanocatalyst that could be effectively used for the removal of environmental pollutants. [ABSTRACT FROM AUTHOR]

In this paper, undoped and Cr-doped VO 2 thin films were fabricated and deposited onto Al 2 O 3 substrates using a sol-gel method. Then, the effects of Cr-doping on the thermochromic, and optical properties of the thin films were investigated. Doping with Cr ions gradually increased the metal-insulator transition (MIT) temperature of the films, while the luminous transmittance (T lum) and the sol modulation efficiency (ΔT sol) gradually decreased. Additionally, Pt/VO 2 /ITO devices and Cr-doped VO 2 devices were prepared to study their threshold switching (TS) properties. For devices fabricated with Cr-doped VO 2 films, both the threshold voltage (V th+) and the OFF-state current decreased as the amount of Cr doping increased. In contrast, the ON/OFF ratio increased from 104 to 105. These results provide insight into the potential for using VO 2 in thermochromic, optical, and TS applications. • The phase transition temperature of Cr-doped VO 2 gradually increases with the increase of Cr concentration. • Optical properties decrease with the Cr3+ doping. • The threshold switching properties of the Cr-doped devices improve significantly. [ABSTRACT FROM AUTHOR]

Abstract New phase pure multiferroic oxides, YIn 1- x Cr x O 3 (x = 0.1, 0.3, 0.5), are synthesized by glycine–aided sol-gel combustion technique using binary oxides and nitrates. YIn 0.9 Cr 0.1 O 3 (I), YIn 0.7 Cr 0.3 O 3 (II) and YIn 0.5 Cr 0.5 O 3 (III) are investigated through powder X-ray diffraction (PXRD), elemental analysis (EDAX), magnetization and polarisation studies. Crystal structure analysis reveals that the sample with 10% Cr3+ (compound I) crystallizes in hexagonal P6 3 cm space group with a = 6.28035 and c = 12.533 Å. The samples with higher concentration of Cr3+ (compounds II and III) crystallize with a mixture of hexagonal and orthorhombic phases. From the detailed magnetic measurements, the compounds are found to exhibit dominating antiferromagnetic behaviour with Neel temperatures of 140, 130 and 125 K for I , II and III, respectively. The Curie-Weiss fittings provide different θ values and the effective magnetic moment, μ eff (2.60 μ B , to 4.23μ B), gradually increases with increasing Cr3+ concentration. The observed values indicate that the spins are not perfectly aligned antiparallel, rather the system exhibits canted antiferromagnetic (AFM) behaviour with weak ferromagnetic interactions. The existence of magnetic ordering is also confirmed by the presence of hysteresis loop below the Neel temperature. The room temperature ferroelectric polarisation loops are indicative of the multiferroic nature of the synthesized compounds. The work reveals the significant role of Cr3+ substitution for structural evolution and enhanced multiferroic behaviour in YIn 1- x Cr x O 3. Graphical abstract Image 1 Highlights • New crystalline Cr3+ doped YInO 3 perovskite compounds have been synthesized. • Size and morphology can be varied with the dopant concentration. • Combined hexagonal and orthorhombic phases observe above 10% Cr3+ ion doping. • Enhancements of Cr3+ ion concentration can improve the multiferroic behaviour. [ABSTRACT FROM AUTHOR]

Metal-organic frameworks (MOFs) gain the popularity among studies due to their exclusive modular and buildable structure, tunable pore size distribution and diversity of functions, which provide tremendous possibilities for the production of high-performance supercapacitors and are considered as one of the vital energy storage materials. Among MOFs, Ni-MOF shows great application outlooks of the energy storage field because of its big specific capacitance and the ability to provide active sites during the reaction. However, the shortcomings of conductivity, rate performance and cycle stability are not very outstanding. This study uses one simple hydrothermal method to synthesize a three-dimensional bimetallic metal nanosheet structure by doping different ratios (including Ni: Cr=1:1, 2:1, 3:1, 4:1, 5:1 and 6:1) in Ni-MOF structure on nickel foam to improve electrochemical performance. Cr-doped materials have abundant active sites due to their large specific surface area. It promotes the reaction of the material surface in the electrolyte, thus enhancing the particular capacitance. At the same time, Cr3+ can also strengthen the lattice stability and gives a more stable nanostructure, effectively promoting conductivity and cycling stability. Therefore, after a series of tests, the obtained electrode material with the optimal ratio of Ni: Cr=4: 1 in Ni-MOF (NC 4 M@NF) reaches high specific capacity up to 853.00 C g−1 at 1 A g−1, better rate capacity of 64.48 % at 10 A g−1 with 3 M KOH in three-electrode system. Besides, the assembled NC 4 M@NF//AC ASC supplies an energy density of 64.41 Wh kg−1 at 850.31 W kg−1, and exceptional cycling stability with only decays 17.89 % after 5000 cycles. [Display omitted] [ABSTRACT FROM AUTHOR]

The voltage fade on lithium-rich layered oxides could be alleviated by substitution of Mn and Ni for Cr. A series of Cr substituted lithium-rich layered oxides, (Li 1.2 Mn 0.6-x Ni 0.2-x Cr 2x O 2 , x = 0, 0.03, 0.065, and 0.1) was prepared by the ethylenediaminetetraacetic acid (EDTA) sol-gel method. For x = 0.03, the reduced voltage fade and a superior capacity retention were obtained, leading to a higher specific energy. When x increased to 0.1, the sample exhibited a comparable voltage fade behavior with the pristine Ni-Mn oxide. The alleviation of the voltage fade was attributed to the suppression of the phase transformation from layer to spinel structures. The reason for this was due to both the reduction of the oxygen loss from the lattice and a decreased content of Mn 3+ at the first charge. Because of the combined effect of these two factors, the conversion of layered oxides to spinel was suppressed, resulting in the alleviation of the voltage fade. [ABSTRACT FROM AUTHOR]

Spinel LiCr○xMn2--xO4 cathode material was synthesized by sol-gel assisted high temperature ball milling method using LiOH·H2O, Cr(CH3COO)3·6H2O and Mn(CH3COO)2·4H2O as raw materials . The crystal structure, surface morphology and charge-discharge performance of materials by doping different amounts of Cr were studied. The results show that the capacity retention rate of the material is greatly improved by Cr doping. The discharge capacity of the material decreases with the increasing doping amounts of Cr. The discharge specific capacity of LiCr0.2Mn1.8O4 is lower than that of LiMn2O4. The charge-discharge performance of LiCr0.05Mn1.95O4 is optimal and its initial discharge capacity is 119.6mAh/g and the discharge capacity retention rate is 97.4% after 40 cycles at a rate of 0.1. Furthermore, the discharge capacity retention rate is 96.3% after 100 cycles at various rates from 0.1 to 2.0. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Northeastern University (Natural Science) is the property of Dongbei Daxue Xuebao and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this study, we used first-principles calculation methods to investigate the effects of Cr doping at different positions on the electronic and optical properties of ZnSe nanowires. We found that the bandgap of the nanowires is larger than that of the bulk. After doping, it was found that the easiest doping position is on the surface, while all positions require heating for doping. After doping, the change in the intrinsic bandgap was very small, and a large number of defect bands appeared in the middle of the intrinsic bandgap, which are mainly composed of Cr(d) orbital electrons, Se(p) orbital electrons, and d-p hybridized bands. The doping of Cr atoms also affects the distribution of LUMO and HOMO. In the parallel direction of the nanowires, the absorption spectrum exhibits a prominent absorption peak near 0.8 eV, which is caused by transitions between defect bands. Therefore, Cr-doped ZnSe (1 1 1) nanowires doped at radius ½ positions are more suitable as mid-infrared laser gain materials. [ABSTRACT FROM AUTHOR]

o-LiMnO2and LiMn1−xCrxO2(x = 0.1) powders were synthesized via hydrothermal method after being calcined. Crystalline structure, surface morphology, and electrochemical properties of the prepared powders are investigated by XRD, SEM, and cyclic voltammetric studies. From the results, it was found that LiMnO2cathode with a small amount of doping Cr is mostly orthorhombic forms. It could not only affect the structure of the specimens, but also improve cycling performance and reversible capacity and it could reach 190 mAh/g after 50 cycles. [ABSTRACT FROM PUBLISHER]

A series of Cr-doped multiferroelectric FeBiO 3 nanoparticles were synthesized via a facile sol gel method. The resultant Cr-doped FeBiO 3 was characterized by means of different techniques, such as scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), transmission electron microscopy (TEM), X-ray powder diffraction (XRD) and electrorheological (ER) tests. Under an external electric field, electrorheological properties of the suspension containing such Cr-doped and undoped FeBiO 3 particles were investigated by steady shear experiments. It was found that the suspension of Cr-doped FeBiO 3 particles possesses a better ER effect than that of pure FeBiO 3 particles. Furthermore, different Cr-doped concentration plays an important role on the ER behavior. Combining the dielectric analysis, the enhanced ER effect of Cr-doped FeBiO 3 suspension can be attributed to the improved interfacial polarization. [ABSTRACT FROM AUTHOR]

Cationic and anionic doping in LiNi0.5Mn1.5O4 has been prepared via a solid state method. The effect of substitution on the structure, morphology, and electrochemical properties were investigated. The XRD and Raman results indicate that all synthesized materials have a phase-pure spinel structure with a space group of Fd3m and no obvious impurity phase peaks. Excellent cycle life is measured for these 5V Cr and (or) F-doped electrodes. When the charge/discharge rate returns to 1C after the test of rate capability (0.1-5C), the capacity can be completely recovered and the capacity retention is about 98.6%, 98.8% and 96.2% after 100 cycles for LiNi0.45Cr0.05Mn1.5O4, LiNi0.45Cr0.05Mn1.5O3.9F0.1 and LiNi0.5Mn1.5O3.9F0.1, respectively. Furthermore, rate capability is greatly influenced by the relative content of Mn3+. Cr and (or) F substitutions supply an efficient process to tune the Mn3+ concentration in the lattice. [ABSTRACT FROM AUTHOR]

Abstract: Immobilized photocatalysts with high catalytic activity under UV light were prepared by growing Cr-doped ZnO nanorods on glass substrates by a hydrothermal method. The effects of Cr dopant on the surface texture, crystallinity, surface chemistry, and photoinduced charge separation and their relation with the photocatalytic degradation of Cr-doped ZnO were investigated by scanning electron microscopy, diffuse reflectance spectra, photoelectrochemical scanning electrochemical microscopy, and X-ray photoemission spectroscopy. Adding the appropriate amount of Cr dopant is a powerful way to enhance the separation of charge carriers in ZnO photocatalyst. The photocatalytic activity was improved due to the increase in surface oxygen vacancies, the separation of charge carriers, modification of the band gap, and the large surface area of the doped ZnO nanorod photocatalyst. [Copyright &y& Elsevier]

LiNiMnCoCrO ( x=0, 0.01, 0.025, 0.05) materials were synthesized by Cr substitute of Mn to enhance their electrochemical properties. The structure and electrochemical properties were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and charge/discharge tests. The materials maintained the α-NaFeO type layered structure and the discharge capacities were also increase by doping appropriate amount of Cr. The sample with x = 0.025 exhibited the highest discharge capability of 181.6 mAh g and the best cycle performance. EIS measurement showed that the Cr-doped electrode had the lower resistance impedance increase during cycling. The chemical diffusion coefficient of Li ion ( D ) was measured by potentiostatic intermittent titration technique (PITT). The result showed that D in Cr-doped electrode was faster than that of the un-doped one. [ABSTRACT FROM AUTHOR]

Abstract: Nitrogen defects and their effect on the ferromagnetism (FM) in Cr-doped GaN have been systematically investigated by first-principles. Four considered configurations including one N vacancy (V N), single substitutional Cr, double substitutional Cr, and complex of Cr–V N are all ferromagnetic. The lowest energy arrangements for double Cr-doped (or Cr–V N) GaN occur at the nearest Cr–Cr (or Cr–V N) distance. One Cr contributes 84.3% of the total magnetic moment (2.533 μ B), while one Cr–Cr pair leads to 5.998 μ B moment (more than twice moment of one Cr) by the strong d–d spin coupling, which is mediated by two Cr 3d states antiferromagnetically coupling with the “commonly shared” N 2p states, and driven by a double exchange mechanism. The V N can enhance the FM by adding about 1 μ B to the Cr moment but reduce the FM spin exchange interaction between the nearest Cr–Cr pairs, so experimentally, high-performance samples may be synthesized by controlling N pressure. [ABSTRACT FROM AUTHOR]

Abstract: A visible-light-active mesoporous Cr-doped TiO2 photocatalyst with worm-like channels was synthesized using an evaporation-induced self-assembly approach and characterized by X-ray powder diffraction, nitrogen adsorption–desorption, X-ray photoelectron spectroscopy, transmission electron microscope, and UV–vis diffuse reflectance, respectively. The effect of Cr3+ doping concentration on the photocatalytic activity of mesoporous TiO2 was investigated from 0.1 to 1mol%. The characterizations indicated that the photocatalysts possessed a homogeneous pore diameter of about 8nm with high surface area of 117m2/g and a crystalline anatase pore wall doped by Cr3+. Compared with pure mesoporous TiO2, the Cr-doped TiO2 extended the photoabsorption edge into the visible light region. The results of gaseous acetaldehyde photodecomposition showed that mesoporous Cr-doped TiO2 exhibited higher photocatalytic activities than pure mesoporous TiO2 and nonporous Cr-doped TiO2 under visible light irradiation. [Copyright &y& Elsevier]

Abstract: Cr-doped TiO2 thin films were prepared by co-sputtering of titanium and chromium in a cathodic arc plasma evaporation system. X-ray diffraction (XRD), Auger electron spectroscopy (AES), field emission scanning electron microscopy (FE-SEM), and water contact angle measurement were used to characterize obtained films. As-deposited pure titanium dioxide thin films possessed a mostly anatase structure while Cr-doped TiO2 films was amorphous. After annealing at 450 °C for 3 h, amorphous Cr-doped TiO2 films transformed to a mixed anatase (mostly) and rutile phase. Changes in the morphology and composition of the films were examined by FE-SEM and AES. Crystalline Cr-doped TiO2 films became super-hydrophilic after 20 min of exposure under visible light illumination, indicating that the absorption edge shifted from an ultraviolet region for TiO2 to a visible light range for annealed Cr-doped TiO2 films, which is further confirmed by UV–visible spectra. [Copyright &y& Elsevier]

Abstract: Prospective positive-electrode (cathode) materials for a lithium secondary battery, viz., Li[Li0.2Ni0.2−x/2Mn0.6−x/2Cr x ]O2 (x =0, 0.02, 0.04, 0.06, 0.08), were synthesized using a solid-state pyrolysis method. The structural and electrochemical properties were examined by means of X-ray diffraction, cyclic voltammetry, SEM and charge–discharge tests. The results demonstrated that the powders maintain the α-NaFeO2-type layered structure regardless of the chromium content in the range x ≤0.08. The Cr doping of x =0.04 showed improved capacity and rate capability comparing to undoped Li[Li0.2Ni0.2Mn0.6]O2. ac impedance measurement showed that Cr-doped electrode has the lower impedance value during cycling. It is considered that the higher capacity and superior rate capability of Cr-doping samples would be ascribed to the reduced resistance of the electrode during cycling. [Copyright &y& Elsevier]

Abstract: Layered Li[Ni(1−x)/3Mn(1−x)/3Co(1−x)/3Cr x ]O2 materials with x =0, 0.01, 0.02, 0.03, 0.05 are prepared by a solid-state pyrolysis method. The oxide compounds were calcined with various Cr-doped contents, which result in greater difference in morphological (shape, particle size and specific surface area) and the electrochemical (first charge profile, reversible capacity and rate capability) differences. The Li[Ni(1−x)/3Mn(1−x)/3Co(1−x)/3Cr x ]O2 powders were characterized by means of X-ray diffraction (XRD), charge/discharge cycling, cyclic voltammetry, and SEM. XRD experiment revealed that the Li[Ni(1−x)/3Mn(1−x)/3Co(1−x)/3Cr x ]O2 (x =0, 0.01, 0.02, 0.03, 0.05) were crystallized to well layered α-NaFeO2 structure. The first specific discharge capacity and coulombic efficiency of the electrode of Cr-doped materials were higher than that of pristine material. When x =0.02, the sample showed the highest first discharge capacity of 241.9mAhg−1 at a current density of 30mAg−1 in the voltage range 2.3–4.6V, and the Cr-doped samples exhibited higher discharge capacity and better cycleability under medium and high current densities at room temperature. [Copyright &y& Elsevier]

Abstract: Undoped and Cr-doped titanium oxide thin films were deposited by using D.C. reactive sputtering technique. The films, deposited onto unheated glass substrates, show an amorphous structure as observed by XRD. SEM, AFM and EPR experiments evidence that Cr-doped samples are nanocrystalline and they are more compact than the undoped films. It was found that, by chromium doping, some parameters (optical transmittance, optical constants and optical band gap) significantly change. The decrease in optical band gap from 3.27 to 2.91eV, means that the material becomes more absorbing by chromium doping and an extension of its photocatalytic activity to the visible part of the absorption spectrum, can be realized. [Copyright &y& Elsevier]

[Display omitted] • Effect of Cr as dopant on the electronic properties of the InP 3 monolayer was explored. • Adsorption behavior of H 2 , C 2 H 2 and CH 4 on InP 3 -based monolayers was discussed. • Gas sensing mechanism of the Cr-InP 3 material to H 2 , C 2 H 2 and CH 4 was analyzed. • Conductivity and recovery time of Cr-InP 3 adsorption systems were evaluated. Transition metal doping plays a significant role to regulate the electronic properties of the material substrates. In this paper, the effect of Cr dopant on InP 3 monolayer and its adsorption performances to H 2 , C 2 H 2 and CH 4 were studied to explore the application potential of Cr-InP 3 for three dissolved gases in transformer oil with density functional theory (DFT). The adsorption behavior of intrinsic and Cr-doped InP 3 monolayers to three gas molecules were simulated in terms of the charge transfer, density of states and molecular orbital, etc. Results illustrated that the electronic structure of InP 3 monolayer could be sharply swayed with Cr dopant, as confirmed by the obviously asymmetry of densities of states around the Fermi level and the generation of magnetic moment of whole system. Besides, the Cr doping with high activation could effectively improve the adsorption properties of InP 3 monolayer for three gas molecules. The Cr-InP 3 monolayer shows more perfect adsorption performance towards C 2 H 2 molecule in all Cr-InP 3 adsorption systems, and might be a promising sensitive material for detection of C 2 H 2 gas. The electrical conductivity and recovery time of Cr-InP 3 adsorption systems were discussed to evaluate the applicability of the proposed material in three dissolved gases. [ABSTRACT FROM AUTHOR]

• Cu 0.7 Co 0.3 Fe 2−x Cr x O 4 ferrite nanoparticles were synthesized by sol-gel auto-combustion technique. • XRD, FESEM-EDS, TEM, FT-IR spectroscopy, dc electrical resistivity, and VSM studies were conducted. • Substitution of Fe3+ by Cr3+ in Cu 0.7 Co 0.3 Fe 2−x Cr x O 4 affects the Coercivity and saturation magnetization. • Cu 0.7 Co 0.3 Fe 1.95 Cr 0.05 O 4 delivered the lowest saturation magnetization (25.23 emu/g). • Non-monotonic variation of the structural and magnetic parameters have been recorded. Using sol-gel auto combustion technique complex ferrite nanoparticles have been synthesized. Characterization with the help of X-ray diffraction (XRD) revealed that the synthesized materials Cu 0.7 Co 0.3 Fe 2−x Cr x O 4 are of a single-phase cubic spinel structure with Fd-3 m space group. And also, the samples' crystallite sizes calculated using XRD data yielded in the range of 19.28–32.92 nm. The lattice constants are calculated to be between 8.4099 Å and 8.4441 Å. The FTIR results revealed that the spinel structure remained undisturbed even after the Cr ions were doped. FESEM images display the materials constitute polygonal-shaped grains though at times irregularly shaped gains with slight agglomeration appear. EDS analysis confirmed that the sample contained the constituent elements. A decreasing pattern in DC resistivity with an increase in temperature was observed, ensuring the semiconducting character of the ferrites under investigation. VSM was utilized to characterize and estimate the magnetic features like magnetic saturation and coercivity of the samples. [ABSTRACT FROM AUTHOR]

Chromium-doped bismuth telluride (Bi 2−x Cr x Te 3) diluted magnetic semiconductor nanocrystals were successfully synthesized in a glass matrix by the fusion method with nominal Cr concentrations of x = 0.00, 0.05, and 0.10. Transmission electron microscopy confirmed the growth of nanocrystals with an average diameter of ~5.0 nm. Shifts in X-ray diffraction peaks with increasing x indicated substitutional inclusion of Cr ions (occupying Bi sites - Cr Bi) in the Bi 2 Te 3 structure. The absorption spectra for x = 0.05 and 0.10 show two intense spin-allowed bands at ~425 and 635 nm and two minor spin-forbidden bands at ~650 and 685 nm. These bands were attributed to the Cr3+ d-d transitions, according to the crystal field theory. Finally, electron paramagnetic resonance spectra from the Bi 2−x Cr x Te 3 nanocrystals displayed Cr3+ characteristics with spin 3/2 in the d3 state, thereby confirming the trivalent state of Cr ions in the Bi 2 Te 3 structure. • Cr3+-doped Bi 2 Te 3 NCs were growth in borosilicate host glass. • Structural properties of Bi 2-x Cr x Te 3 are investigated for x = 0.00, 0.05, and 0.10. • Cr3+ spin-allowed d–d transitions in the octahedrally-coordinated environment. • Quantum confinement and effects Exchange sp-d. [ABSTRACT FROM AUTHOR]

As a kind of chalcogenide alloy, phase change material has been widely used as novel storage medium in optical disk or electrical memory. In this paper, femtosecond pulses are used to study the reversible phase transition processes of Cr-doped Sb2Te3 films with different initial states. The SET processes are all induced by multiple pulses and relate to the increase of crystallized partial in the irradiated spot. When the Cr concentration is 5.3 at % or 10.5 at %, the crystallization mechanism is still growth-dominated as Sb2Te3, which is beneficial for high speed and high density storage, whereas the necessary crystallization energy increases with more Cr-dopants, leading to higher amorphous thermal stability. RESET results by multiple pulses show that Cr-dopants will not increase the power consumption, and the increase in Cr-dopants could greatly increase the antioxidant capacity. Single-pulse experiments show that the RESET process involves the competition of melting/amorphization and recrystallization. The reversible SET/RESET results on different initial states are quite different from each other, which is mainly due to the different surroundings around the irradiated spot. Crystalline surroundings provide higher thermal conductivity and lead to easier crystallization, whereas amorphous surroundings were the reverse. All in all, Cr-doped Sb2Te3 films with suitable composition have advantages for storage with high density, better thermal stability, and lower power consumption; and the suitable initial states could ensure better reversible phase transition performances.