Papers by Author: Hai Feng Chen

Abstract: Using Yb(NO₃)₃•6H₂O and Fe(NO₃)₃•9H₂O as raw material, the YbFeO₃ nanoparticles were synthesized by microwave assisted method. The YbFeO₃ nanoparticles were characterized by thermogravimetry and differential thermal analysis (TG-DTA), powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-visible diffuse reflectance spectroscopy (DRS). It was found that the prepared YbFeO₃ show an average grain size of 80 nm in diameter, and strong visible-light absorption with absorption onset of 608 nm, indicating a narrow optical band gap of 2.04eV. Consequently, the YbFeO₃ nanoparticles show high photocatalytic activity for decomposition of methylene blue under visible-light irradiation.

Abstract: Silver ions (Ag⁺) used as secondary ion, cetyl trimethyl ammonium bromide (CTAB) used as surfactant and ascorbic acid(AA) used as reducing agent, the gold(Au) nanorods were synthesized by seed-mediated growth method. The resulting substrates have been characterized by UV-vis spectroscopy. The law of Au nanorods growing was researched by controlling concentration of CTAB, Ag⁺, seed-fluid and AA. The results showed that the optimum reaction conditions are 0.10 M CTAB, 0.1×10^-3 M Ag⁺, 0.0056×10^-3 M AA, 0.48×10^-6 M seed-fluid and system temperature 30°C.

Abstract: WO₃ nanocrystals have been successfully synthesized via an ion induced auxiliary hydrothermal method. The experiment products were characterized by powder X-ray diffraction (XRD) and the Photocatalytic oxidation performance of products were characterized by using the photocatalytic oxidation of methyl orange under the condition of hydrogen peroxide. The optimal amount of catalyst required for catalytic oxidation experiments and the concentration of methyl orange (MO) were determined. The experimental results indicated that with he enhancement of metallicity in alkali main group, the photocatalytic activity of the WO₃ induced by alkali metal cation increased; The SO₄^2- has higher induce catalytic activity than Cl- when the type and quantity of cation are the same; however, the ion induction on the impact of surface area is quite different, and it founded that they comply with this regular pattern, that is Na+> K+> Li+ and SO₄^2-> Cl-.

Abstract: Using auminum nitrate nonahydrate and titanium dioxide nanowires as the main raw material, Al₂O₃/TiO₂ composite powers were prepared by the hydrothermal method at 200 oC for 24 hours. And the samples are characterized by XRD, nitrogen adsorption and desorption. The results show that the samples are corundum and rutile, and specific surface area is nearly 155 m2/g. Otherwise we tested samples for adsorption capacity of Congo red at different times, temperature and initial concentration under visible light irradiation. We found that it is the maximum adsorption efficiency (~107 mg/g) at the temperature of 50 oC, within one hour to reach the adsorption saturation.

Abstract: Phthalocyanine sensitization nano-TiO2 have been successfully synthesized by controlling TiO2's nuclear growth and CoPcTs adsorption simultaneously via a hydrothermal way by using TiO₂, NaOH and CoPcTs as raw materials. XRD, BET, TG-DTA and FI-IR were used to characterize the features of the as-synthesized phthalocyanine sensitization TiO₂ nanowires. The results showed that anatase nano- TiO₂ with phthalocyanine sensitization have been prepared after heat treatment and cyanine materials are easily decomposed when the temperature above 450 °C; the specific surface area TiO₂ and phthalocyanine sensitization nano-TiO₂ is 42.2 m²/g and 110.5 m²/g, respectively. Methyl orange dyes were chosen to test the photocatalytic activities of the as-prepared sample in this experiment, and it found that the loading of 1% wt CoPcTs was the best.

Abstract: As titanium source tetrebutyl titanate modified by reflux preparation, the clean solution containing the nano-TiO₂ had been prepared by hydrothermal synthesis method. Then the solution was added to the chloroform solution which containing the poly (hydroxybutyrate-co-valerate) (PHBV), and the loading nano-TiO₂ modified PHBV film was prepared by solution casting processes. X-ray diffraction (XRD) and UV-visible transmission spectra (UV-vis) were used to characterized; in the photocatalytic experiment, 10 ml 5 mg/L methyl orange solution with the 10 mg catalyst, the fade rate reached 90% after 120 min. The thin film obtained in this method has characteristics of high transmittance, high photocatalytic activity, recycling, non-toxic and the loading nano-TiO₂ of uniform dispersion.

Abstract: In this paper, TiO₂/Ag/TiO₂ and TiO₂/Ag/ZnS films were prepared by evaporation coating (EC) and magnetron sputtering (MS). To test the resistance and light transmission rate to characterize the coating effect, both the size of indirect resistance that the relative thickness of the situation. By comparing the single magnetron sputtering and evaporation coating fabricated by the two transparent conductive oxide films (TCO) material conductivity and light transmission properties, determine a reasonable process. Firstly, the first layer is TiO₂ film by magnetron sputtering, and then coating Ag film and ZnS film plated by evaporation, the final form of TiO₂/Ag/ZnS film, which ha_{Subscript text}d much higher transmittance than TiO₂/Ag/TiO₂ at the same resistanc_{Subscript text}e.

Abstract: In this experiment, pyrophyllite as the main materials used the flame photometer to measure adsorption. Using the qualitative analysis of the samples of XRD with internal structure and found that pyrophyllite used in the experiment as a natural mineral, the presence with other minerals. Meanwhile, scanning electron micrographs (SEM) from the display showed that the effect of pyrophyllite adsorption for cations should be more significant. Therefore, this experiment focused on the time, Na⁺ concentration, on the pyrophyllite and different pyrophyllite concentrations (adsorbent dosage) effect on the adsorption, in addition to the adsorption dynamics. The results showed that pyrophyllite adsorption sodium in the best time of equilibrium was 20 minutes, the concentration of NaCl was 50 mg/L, pH = 7, temperature was 313 K, the concentration of pyrophyllite was 5 mg/L.

Abstract: The LaFeO3 nanoparticle was synthesized using Fe(NO3)3 and La(NO3)3 as starting materials by homogeneous precipitation method. The as-prepared LaFeO3 product was characterized by powder X-ray diffraction (XRD), scanning electron microscopy (SEM) and UV-visible diffuse reflectance spectroscopy (DRS). XRD and SEM demonstrate the successful synthesis of single phase perovskite LaFeO3 and with 60-80 nm particle size. It was found that the as-prepared LaFeO3 shows strong visible-light absorption with absorption onset of 532 nm, indicating a narrow optical band gap of 2.33 eV. Furthermore, the as-prepared LaFeO3 shows high visible-light photocatalytic activity for decomposition of methylene blue in comparison with the commercial Degussa P25.

Abstract: To prolong blast furnace campaign life, a great deal of research work has been carried out on the structure of stave cooler in the past decades, which, in turn, produced favorable results. However, due to the different thermal expanding property of the metal stave from that of the brick lining, the latter is subjected to crack, slide and damage. To solve the problem, a new stave cooler has been developed in this paper. Thus, a certain amount of anchors were welded on the traditional stave cooler, the unshaped gunning material can be fixed by anchors and the whole-lining be formed by gunning. The results of thermal simulating indicates: the bonding strength between the surface of stave cooler with anchors and the gunning lining is much higher than that between the surface of traditional stave cooler and the brick lining. Consequently, the service life of blast furnace will be extended. The optimizing design of the anchor was also described in the paper.