查找使用阿拉丁产品的科研文献

Controllable construction of ZnWO4 nanostructure with enhanced performance for photosensitized Cr(VI) reduction

Hongbo He,Zhuangzhu Luo,Zhen-Yu Tang,Changlin Yu

Structure controlled ZnWO 4 nanomaterials were fabricated by a facile hydrothermal reaction . The nanorod-like ZnWO 4 with exposed (111) facets exhibits significant promoting effect for Cr 6+ reduction than that of noncrystalline ZnWO 4 nanoparticles . Specifically, the photocatalytic performance of ZnWO 4 -T14 for Cr 6+ reduction is 9.8 times higher than that of ZnWO 4 -T0. The effect of Zn 2+ on the concentration-absorbance (C-A) curve of K 2 Cr 2 O 7 solution was evaluated and investigated systemically, and adding Zn 2+ can improve the UV–vis spectrum detection sensitivity of K 2 Cr 2 O 7 solution. Methylene blue (MB) as a photosensitizer to enhance the photocatalytic activity of ZnWO 4 for Cr 6+ reduction is reported for the first time. In particular, the photocatalytic activity of ZnWO 4 -T14 for Cr 6+ reduction is 96.7% in 10 mg/L MB solution, which is 65.1% higher than that in aqueous solution. Moreover, the ZnWO 4 -T14/MB possesses excellent stability, and the reduction rate of Cr 6+ remains above 90% after four cycles. We believe that the photosensitized strategy is a promising methodology in the treatment of heavy metal ion due to its superior photocatalytic activity and stability.

Immobilization of Cr(VI) from solution by a graphene oxide-nZVI/biochar composite

Jingge Shang,Jie Gao,Junting Xi,Yingjie Wang,Fangyu Ji,Ruijun Li

A graphene oxide (GO)—nanoscale zerovalent iron (nZVI)—biochar composite (GO-nZVI/BC) was synthesized prior to characterization by X-ray diffraction (XRD), vibrating sample magnetometer (VSM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy analyses. Batch experiments were performed at different initial Cr(VI) concentrations, contact times, and solution pH values. The effects of coexisting anions and chelating agents were also examined. The results indicated that the removal of Cr(VI) was highly pH-dependent and reached a maximum capacity at pH of 2. The equilibrium data were fitted well with the Langmuir isotherm model, and the kinetic data fitted better with the pseudo-second-order kinetic model. The increasing concentrations of EDTA in aqueous solutions were favorable to the removal of Cr(VI), while significantly inhibited adsorption. Furthermore, the GO-nZVI/BC maintained ~84.5% of its original capacity after aging in the air for 25 weeks. Based on the removal efficiency, GO-nZVI/BC can be considered to be an effective material for water treatment applications. Practitioner points Biochar-supported graphene oxide-coated nanoscale zerovalent iron (GO-nZVI/BC) was synthesized and used to treat Cr(VI) from solution. Cr(VI) removal was pH-dependent and obeyed the Langmuir isotherm model and pseudo-second-order model. GO-nZVI/BC maintained ~84.5% of its original capacity after aging for 25 w in the air. Graphical TEM and Magnetic Field of GO-nZVI/BC and its removal capacity of Cr(VI).

Amine-Grafted MIL-101(Cr) for Superior CO2 Capture: Performance, Kinetics, and Thermodynamics

Yandi Li,Songyi Ji,Rong Zhang,Xiaoling Li,Xiandong Hao,Ning Zhao,Bo Wang,Zhiyong Xu,Wenbo Zhao

Carbon dioxide capture is critical for mitigating climate change. Amine-functionalized MIL-101(Cr) shows great promise due to its high stability and tunable porosity. We optimized its synthesis (160°C, 24 h, 150°C activation) and investigated diethylenetriamine (DETA) loading effects. The 50 wt% DETA composite achieved a CO 2 uptake of 1.25 mmol/g at 30°C and 0.1 bar, nearly six times that of pristine MIL-101(Cr). Kinetic and isotherm data were well described by the pseudo-second-order and Langmuir models. Thermodynamic analysis revealed Δ H = −54.78 kJ/mol and Δ S = −142.13 J/(mol K), confirming an exothermic, chemisorption-dominated process. We further optimized adsorption/desorption conditions, identifying optimal working temperatures of 269.47 K (adsorption) and 388.20 K (desorption). This work provides clear guidance for designing high-performance metal–organic framework (MOF)-based CO 2 capture materials.

Enhanced Luminescence Performance of Cr-Doped CaMgSi2O6 Phosphor via Alkali Metal Ion Codoping

Lizhen Zhang,Lehui Liu,Feifei Yuan,Yisheng Huang,Zhoubin Lin

Enhancing the luminous intensity of near-infrared (NIR) phosphors is critical for practical applications. This study demonstrates that codoping charge-compensating ions (Li+, Na+, and K+) significantly improves the fluorescence emission intensity and quantum efficiency of Cr3+-doped CaMgSi2O6 (CMSO:Cr) phosphors. Optimal enhancements were achieved with specific ion concentrations: the CMSO:0.01Cr phosphor codoped with 0.8 at. % Na2CO3 exhibited a 1.8-fold increase in emission intensity, while the CMSO:0.04Cr phosphor codoped with 1.5 at. % Li2CO3 demonstrated an 8-fold enhancement. Charge compensation also improved the internal quantum yield (IQY) and photoelectric conversion efficiency without compromising the thermal stability. Mechanistic insights from absorption/emission spectra, electron paramagnetic resonance (EPR), and fluorescence lifetime analyses revealed that alkali metal ions occupy defect sites, suppress nonradiative recombination, and simplify emission profiles by eliminating defect-induced luminescent centers.

Lithiation-Driven Phase Engineering Unlocking Broadband NIR Emission in Cr-Doped Zinc Tantalate

Xiaohong Zhang,Siyuan Lin,Changfu Xu,Haiyan Shi,Kai Li,Pan Zhou,Pengbo Lyu,Lizhong Sun

Structural phase evolution is among the most powerful tools for tuning material properties, enabling advancements in catalysis, dielectrics, optoelectronics, and photoluminescence. Such an evolution can significantly enhance the near-infrared (NIR) emission properties of Cr3+-doped phosphors. Herein, we present, to the best of our knowledge, the first observation of lithiation-induced continuous structural phase evolution in ZnTa2O6 phosphors, driven by Li+ incorporation. This evolution proceeds systematically from orthorhombic ZnTa2O6 (Pbcn) to tetragonal ZnTa2O6 (P42/mnm) and ultimately to trigonal (Li0.5Zn0.5)TaO3 (R3c) as the Li+ content increases. When doped with Cr3+, the NIR emission peak exhibits a progressive blue shift, moving from 949 to 885 nm and eventually to 862 nm, in tandem with the phase evolution. This phase evolution also yields significant enhancements in photoluminescent intensity, internal quantum yield (IQY), and photoluminescence thermal stability. Our findings establish a new paradigm for designing highly efficient ultra-broadband NIR phosphors and offer a foundation for developing tantalate-based materials with versatile functionalities, including improved dielectric properties.

Cr-Doped Fe1–xCrxF3·0.33H2O Nanomaterials as Cathode Materials for Sodium-Ion Batteries

Chao Zhang,Mingxia Yan,Wenting Li,Ce Han,Jie Li,He Zhao,Guixiao Jia,Shengli An,Xinping Qiu

Due to the high theoretical specific capacity and low cost, FeF3·0.33H2O has become one of the potential choices of cathode materials for sodium-ion batteries. However, the poor intrinsic conductivity limits its practical applications. Herein, the atomic substitution is used to improve its intrinsic conductivity. The first-principles calculation results show that Cr3+ doping can reduce the band gap of FeF3·0.33H2O to improve its intrinsic conductivity. The discharge specific capacity of Fe0.95Cr0.05F3·0.33H2O with a narrowest band gap is 194.02 mA h/g at 0.1 C within the range of 1.4–4.0 V, which is higher than that of FeF3·0.33H2O (136.47 mA h/g). Using the electrochemical impedance spectroscopy and galvanostatic intermittent titration technique tests, it is found that Rct of Fe0.95Cr0.05F3·0.33H2O is reduced and DNa+ is almost unchanged, as compared to FeF3·0.33H2O.

Crystal structures and magnetocaloric properties of Li5ASrMB12O24(A = Mg, Zn; M = Cr, Ni)

Yuwei Chen,Jingcheng Feng,Feidi Fan,Jun Shen,Guochun Zhang,Heng Tu

Three new transition-metal-based borate crystals, Li 5 MgSrMB 12 O 24 (M ​= ​Cr, Ni) and Li 5 ZnSrNiB 12 O 24 , were obtained using the high temperature solution method. Their structures were determined by the single crystal X-ray diffraction, which crystallize in the trigonal R 3 ¯ space group. The [B 3 O 11 ] groups in the structures lead to the long distance between two nearest magnetic ions, which can reduce the interaction of adjacent magnetic centers. The magnetic properties and thermal stabilities of the title compounds were also investigated. The results indicated that Li 5 MgSrCrB 12 O 24 has stable chemical-physical properties and its maximum –ΔS m value of 14.33 ​J ​kg −1 ·K −1 at 2 ​K for Δμ 0 H  ​= ​9 ​T reaching 88.6% of the theoretical paramagnetic limit, suggesting its potential application on the magnetic refrigeration.

Study on Amino-functionalized Porous Carbon Materials for MB and Cr(VI) Adsorption

Song Jie,Chen Lijun,Niu Yuhua,Wei Zhiqiang,Sun Yonghui

From the perspective of environmental protection, high removal rate, reusable and degradable, amino-functionalized porous hydrogel material P-(EA-β-CD/KHA/AC) was synthesized by introducing ethylamino cyclodextrin, humic acid, and activated carbon, using polyacrylic acid as the carrier. MB and Cr (VI) are common wastewater pollutants, thus, Such contaminants must be removed from the water. The gel materials before and after adsorption were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The removal of MB and Cr(VI) showed high adsorption capacity. At 298 K and pH 8, the adsorption capacities of P-(EA-β-CD/KHA/AC) hydrogel for MB and Cr(VI) were as high as 262.31 and 170.12 mg/g, respectively, and the removal rates were 98.96% and 70.27%, respectively. The adsorption behavior follows the pseudo-second-order kinetic equation, conforming to the Langmuir model; and through intermolecular forces, π–π conjugation, chelation, and other interactions, entropy-increasing, endothermic, and spontaneous process is formed. The regeneration and degradability experiments of P-(EA-β-CD/KHA/AC) hydrogel were conducted and its recycling performance was verified.

Rational design of BixFeyVO4/g-C3N4 heterojunction for photocatalytic reduction of Cr(VI)

Qiang Li,Hao Zhou,Meng Tan,Lingxuan Yang,Xiao Hu,Guoxiang Yang,Hao Du,Qing Wei,Qi Wang

High visible light utilization and rapid charge separation are of great importance for environmental photocatalysis . Single photocatalyst always suffers from high recombination of photogenerated electron-hole pairs and low redox ability. Elemental doping and heterojunction construction are effective approaches to improve the photocatalytic performance. Herein, we designed and synthesized a novel Bi x Fe y VO 4 /g-C 3 N 4 (BFC) binary heterojunction via facile coprecipitation followed by calcination processes. The doping of Fe endows BiVO 4 with narrower bandgap, which boosts its light response and redox ability. The construction of heterojunction facilitates charge separation that makes BFC heterojunction displaying much higher photocatalytic activity than those of single semiconductors. The highest Cr(VI) photoreduction rate ( k ) of BFC binary heterojunction is 78 (45) times of BiVO 4 (FeVO 4 ). Additionally, the binary heterojunction can still maintain high photoreduction efficiency (98%) of Cr(VI) even after five cycling tests showing excellent photocatalytic stability. This research provides novel idea for synergistic application of doping and heterojunction in environmental photocatalysis.

The overlooked role of Cr(VI) in micropollutant degradation under solar light irradiation

Tao Yang,Cui Huang,Linqian An,Ge Zeng,Juan Li,Changyu Liu,Xiaolong Xu,Jianbo Jia,Jun Ma

Hexavalent chromium (Cr(VI)) is ubiquitous in natural environments, whereas its role in the transformation of coexisting contaminants may have been overlooked. In this work, it was reported for the first time that the irradiation of Cr(VI) by solar light (solar light/Cr(VI) system) could effectively degrade various micropollutants with different structures. The removal efficiency of selected micropollutants was increased by 13.3–64.8% by the solar light/Cr(VI) system compared to that by direct solar photolysis. Meanwhile, the oxidation rates were enhanced by 2.2–21.5 folds, while they were negligible by Cr(VI) oxidation alone. Experiments by specific scavengers, probe compounds, fluorescence absorbance, and electron spin resonance analysis demonstrated that hydroxyl radical (•OH) was the major reactive species in the solar light/Cr(VI) system. Further experiments showed that the generation of •OH was closely related to the intermediate Cr(V) generated from Cr(VI) reduction, and Cr(V) could be re-oxidized back to Cr(VI). Increasing solution pH negatively affected model micropollutant (carbamazepine (CBZ)) degradation by the solar light/Cr(VI) system, mainly due to the decreased quantum yield of •OH at higher pH. Coexisting sulfate ions showed negligible effect on CBZ degradation in the solar light/Cr(VI) system, while the presence of bicarbonate , chloride, and humic acid inhibited CBZ degradation to varying degrees, owing to their diverse scavenging effects on •OH. Furthermore, moderate CBZ degradation was also achieved by natural solar light photolysis of Cr(VI). This study demonstrated the pivotal role of Cr(VI) in the transformation of micropollutants under solar irradiation, which advances the understanding of the fate of micropollutants in natural environments.

Cellulose bridged carbonate hydroxyapatite nanoparticles as novel adsorbents for efficient Cr(VI) removal

Jing Cui,Xinying Li,Shoucheng Ma,Wei Wei

Enhanced adsorption and photocatalytic Cr(VI) reduction and sterilization of defective MoS2/PVP

Yingge Zhang,Hongfen Li,Xiaolei Zhang,Hanfang Zhang,Wang Zhang,Hongwei Huang,Hongling Ou,Yihe Zhang

The exploration of novel nanomaterials to resolve the issues of water pollution with the aid of photocatalytic technology has always been a research hotspot. MoS 2 is acknowledged to be one of the promising photocatalysts for its interesting layered structure, suitable band gap, and good chemical stability. However, the fast recombination of photogenerated electrons and holes within the MoS 2 impedes its extensive application. Here, hydrophilic polymer (polyvinyl pyrrolidone, PVP) and sulfur vacancy (Vs) are simultaneously introduced into the MoS 2 nanosheets to achieve high-efficient photocatalytic hexavalent chromium Cr(VI) removal and antibacterial performance. The incorporation of PVP greatly enhances the adsorption capacity of MoS 2 , and creating Vs essentially strengthens the photogenerated carrier separation of MoS 2 . As a result, the Cr(VI) removal efficiency of MoS 2 -PVP with an appropriate Vs concentration is up to 99.5 % for 3 h. Meanwhile, MoS 2 -PVP with a relatively higher Vs concentration displays a superior Escherichia coli (E. coli) removal efficiency of 91.8 % within 30 min with the initial E. coli concentration of ∼1.0 × 10 7 CFU/mL. This study extends photocatalysts to a higher level in designing advanced materials for environmental remediation and establishes a feasible platform for emphasizing the versatility of defect engineering in regulating catalytic activity.