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A selective extraction process for recovering vanadium (IV) over chromium was proposed with use of a mixed extractant consisting of di(2-ethylhexyl) phosphate (D2EHPA) and tri-n-butyl phosphate (TBP). The influence of various factors, which included the initial aqueous pH value, the concentration of leach solution and D2EHPA, phase ratio (O/A), extraction equilibrium time and extraction temperature in the extraction process on the separation of V and Cr was investigated. Under the condition of the optimum extraction, vanadium extraction was above 94.0%. Meanwhile, under the optimum stripping conditions, the vanadium stripping was above 93.0% utilizing 1.5 mol/L sulfuric acid as the effective stripping reagent. The regeneration and reusability of the loaded organic phases after stripping were discussed. In addition, continuous three-stage extraction and stripping strategy indicated that the aggregate loss of vanadium was 0.885% and that the purity of vanadium was more than 99.9%. Under the condition of the optimum precipitation, when the pH value of the stripping solution was adjusted to 7.0 with ammonia water, the precipitation efficiency reached 99.93%. The calcination conditions (above 680 °C in air) were finally determined by TG-DTA and TG-MS experiments, and the V2O5 obtained by calcination was characterized by XRD. Additionally, a method for detecting impurity elements in vanadium matrix without interference was established. The recovery technology has practical significance in enlarging production scale, reducing specific energy consumption and cost, and realizing automatic control in vanadium leaching process. [ABSTRACT FROM AUTHOR]

Functional aerogels composed of regenerated cellulose and tungsten oxide were fabricated by implanting tungsten-oxide nanodots into regenerated cellulose fiber. This superfast photochromic property benefitted from the small size and even distribution of tungsten oxide, which was caused by the confinement effect of the regenerated cellulose fiber. The composite was characterized using XRD and TEM to illustrate the successful loading of tungsten oxide. The composite turned from pale white to bright blue under ambient solar irradiation in five seconds. The evidence of solar absorption and electron paramagnetic resonance (EPR) demonstrated the fast photochromic nature of the composite and its mechanism. Furthermore, carbon fiber filled with preferential growth tungsten-oxide nanorods was obtained by annealing the photochromic composite in a N2 atmosphere. This annealed product exhibited good absorption across the whole solar spectrum and revealed an excellent photothermal conversion performance. The water evaporation rate reached 1.75 kg m−2 h−1 under one sun illumination, which is 4.4 times higher than that of pure water. The photothermal conversion efficiency was 85%, which shows its potential application prospects in seawater desalination. [ABSTRACT FROM AUTHOR]

Protein phosphorylation regulates and controls protein activity and function, which is the most basic and important part in organisms' lives. However, the low abundance and ionization inhibition of phosphopeptides make it difficult to understand and analyze the protein phosphorylation mechanism. In this study, we synthesize a core‐shell structured magnetic Ti4+‐based immobilized metal ion affinity chromatography material for highly selective enrichment of phosphopeptides. The introduction of negatively charged carbon layer increases the specific surface area and avoids loss of the immobilized Ti4+ during sample loading and washing. The synthesized magnetic superhydrophilic extractant is employed to separate and enrich phosphopeptides from standard protein digests coupled with MALDI‐TOF MS. It exhibits excellent enrichment performance of high selectivity (1 : 2000 molar ratio of β‐casein and BSA), sensitivity (low detection limit of 4 fmol) and preferable reusability (at least 12 times) as well as excellent adsorption capacity of 142.5 mg ⋅ g−1 and high recovery rate of 85.6 %. Moreover, sixteen phosphopeptides and four endogenous phosphopeptides can be accurately identified from non‐fat milk and human serum, further indicating the great potential and bright application in phosphoproteomics analysis. [ABSTRACT FROM AUTHOR]

Chitosan (Cts), a positively charged natural polysaccharide, is employed to functionalize mesoporous titanium dioxide (mTiO2) nanoparticles. The prepared Cts/mTiO2 composite was used as a stationary phase to coat the inner wall of fused‐silica capillary and obtain uniform Cts/mTiO2 film. The Cts/mTiO2 film is applied to detect and enrich phosphopeptides in complex biological samples based on typical in‐tube solid phase microextraction (IT‐SPME) system. This unique Cts/mTiO2 film exhibits excellent enrichment performances of high selectivity (β‐casein and BSA in molar ratio of 1 : 1000), sensitivity (detection limit as low as 40 fmol of β‐casein tryptic digest solution) and high adsorption capacity (124.5 μg mg−1). Meanwhile, the Cts/mTiO2 film possesses preferable reusability and can be reused more than 10 times. These results confirm that the Cts/mTiO2 film possesses potential and satisfactory prospects in phosphoproteomics analysis. [ABSTRACT FROM AUTHOR]

A new method is applied for preparation of yttria-stablilized zirconia(YSZ) nanocrystals. While crystallization occurs on the surface and interface of SrCO(sub 3) nanoparticles, the agglomeration of YSZ particles is inhibited.

A MOF material has been grown on metallic transition metal nitride for electrocatalytic OER. The as-prepared hierarchical NiFe-MOF@Ni3N nano/microsheet array electrocatalyst exhibits a low overpotential of 281 mV at a current density of 200 mA cm−2 with a remarkable stability of 50 h. [ABSTRACT FROM AUTHOR]

Self-supported nickel–iron nitride microsheet arrays coated with carbon are grown on commercial Ni foam (NixFeyN@C/NF) and used as an electrocatalyst for splitting of alkaline seawater. The porous architecture and superhydrophilic/superaerophobic surface ensure sufficient exposure of active sites and mass transfer. The synergetic coupling effect between the carbon coating and NixFeyN facilitates electron transport. The optimal anode (Ni3FeN@C/NF) and cathode (Ni3N@C/NF) electrocatalysts are employed to assemble a two-electrode seawater electrolyzer for overall alkaline seawater electrolysis, which delivers a large current density of 500 mA cm−2 at a low cell voltage of 1.91 V. The superior corrosion-resistance and electron conductivity of the electrocatalyst are responsible for its excellent durability up to 100 hours. This result suggests that transition-metal nitrides coated with carbon offer an effective route to fabricate high-performance and durable hybrid electrocatalysts for hydrogen production from seawater electrolysis. [ABSTRACT FROM AUTHOR]

Low-cost, efficient and stable electrocatalysts are required for large-scale production of hydrogen by industrial scale water electrolysis. We report here a hybrid bifunctional electrocatalyst, composed of amorphous NiFe LDH nanosheets and metallic Ni3N microsheet arrays grown on Ni foam for water splitting in alkaline electrolyte. This electrocatalyst possesses a typical 3D hierarchical heterostructure architecture and affords abundant exposed active sites. The strong coupling and synergistic effects between the NiFe LDH nanosheets and the Ni3N microsheet arrays provide a robust integrated structure and fast electron transfer. The superhydrophilic/superaerophobic properties of the electrocatalyst promote the mass transfer particularly at a large current density. By employing the NiFe LDH@Ni3N/NF as a bifunctional electrocatalyst for overall water splitting, an alkaline aqueous electrolyzer exhibits a low cell voltage of 1.80 V at a current density of 500 mA cm−2 with a remarkable durability of 100 h. The bifunctional NiFe LDH@Ni3N/NF electrocatalyst is a very promising candidate for scale-up industrial implementation of hydrogen production due to its excellent catalysis activity and high stability. [ABSTRACT FROM AUTHOR]

Hexagonal (NH4)xWO3 has emerged as a promising photothermal agent in recent years due to the charge compensation reaction when cation intercalation occurs. We chose the ammonium ion to intercalate into the hexagonal crystal channel of tungsten oxide because of its appropriate ion radius and unique interaction with the hexagonal channel. The transmission electron microscope image shows that the morphology of the as‐prepared (NH4)xWO3 is a nanorod with a 10 nm radius and 50 nm length. The product exhibits strong absorption across the whole near infrared and ultraviolet light spectrum, as well as part of the visible light spectrum. Moreover, it exhibits a photothermal conversion efficiency up to 69.3 % at 808 nm with good photothermal stability, and features excellent biocompatibility during the co‐culture process with MC3T3‐E1 cells. Ammonium was intercalated into the hexagonal crystal channel of tungsten oxide to produce hexagonal (NH4)xWO3 as nanorods with a 10 nm radius and 50 nm length. The product exhibits strong absorption across the whole near infrared and ultraviolet light spectrum, as well as part of the visible light spectrum. Moreover, it exhibits a photothermal conversion efficiency up to 69.3 % at 808 nm with good photothermal stability, and features excellent biocompatibility during the co‐culture process with MC3T3‐E1 cells. [ABSTRACT FROM AUTHOR]

The design of efficient catalysts for the selective oxidation of sp3 C–H bond with air at low temperature is of great importance to the scientific and industrial community. In this work, we design a CeO2–δ modified CuFe2O4 catalyst by a post‐modification method for the selective oxidation of fluorene under an air atmosphere and N‐hydroxyphthalimide (NHPI) at 60 °C. HRTEM results indicate that CeO2–δ nanoclusters sized around 5 nm are successfully modified on the surface of CuFe2O4. XPS and H2‐TPR results show that CeO2–δ modification would favor oxygen transfer at lower temperature due to the synergetic effect between CuFe2O4 and CeO2–δ with rich Ce3+/Ce4+ couples. The results demonstrate that CuFe2O4@CeO2–δ‐0.05 with 4.20 wt.‐% Ce present the best catalytic performance with 94 % conversion of fluorene and excellent reusability at least five times. It is anticipated that the modification of CeO2–δ nanoclusters on the surface leads to increased oxygen activation and transfer to CuFe2O4, which favors the activation of NHPI to phthalimide‐N‐oxyl (PINO) radicals and exhibits an improved catalytic performance. Our results provide some guidance on the design of efficient catalysts by the surface modification strategy. CeO2–δ modification with 4.20 wt.‐% Ce on the surface of CuFe2O4 nanoparticles favors oxygen transfer at lower temperature and leads to better catalytic activity than that of pure CuFe2O4 for the aerobic selective oxidation of fluorene due to the synergetic effect between CuFe2O4 and CeO2–δ with Ce3+/Ce4+. [ABSTRACT FROM AUTHOR]