Haimin Zhang

Sonocatalytic degradation of RhB over LuFeO3 particles under ultrasonic irradiation.

LuFeO3 particles with an average particle size of ∼200 nm were synthesized via a polyacrylamide gel route. The sonocatalytic activity of LuFeO3 particles was evaluated by the degradation of Rhodamine B (RhB) under ultrasonic irradiation, revealing that they exhibit a good sonocatalytic activity. The effects of various experimental factors including ultrasonic frequency (f), reaction solution temperature (T), catalyst dosage (Ccatalyst), initial RhB concentration (CRhB), and pH value on the sonocatalysis efficiency were investigated. It is found that the former four factors have an important influence on the sonocatalytic degradation of RhB, where the best degradation conditions are obtained to be f=60 kHz, T=40 °C, Ccatalyst=4 g L(-1), and CRhB=5 mg L(-1). The pH value has a relatively small effect on the sonocatalytic degradation of RhB compared with other experimental factors. Hydroxyl (·OH) radicals were detected by fluorimetry using terephthalic acid as a probe molecule, revealing that they are produced over the ultrasonic-irradiated LuFeO3 particles. The addition of ethanol leads to a quenching of ·OH radicals and a simultaneous decrease in the RhB degradation. This indicates that ·OH radicals are the primary active species responsible for the dye degradation.

Photocatalytic reduction synthesis of SrTiO3-graphene nanocomposites and their enhanced photocatalytic activity

SrTiO3-graphene nanocomposites were prepared via photocatalytic reduction of graphene oxide by UV light-irradiated SrTiO3 nanoparticles. Fourier transformed infrared spectroscopy analysis indicates that graphene oxide is reduced into graphene. Transmission electron microscope observation shows that SrTiO3 nanoparticles are well assembled onto graphene sheets. The photocatalytic activity of as-prepared SrTiO3-graphene composites was evaluated by the degradation of acid orange 7 (AO7) under a 254-nm UV irradiation, revealing that the composites exhibit significantly enhanced photocatalytic activity compared to the bare SrTiO3 nanoparticles. This can be explained by the fact that photogenerated electrons are captured by graphene, leading to an increased separation and availability of electrons and holes for the photocatalytic reaction. Hydroxyl (·OH) radicals were detected by the photoluminescence technique using terephthalic acid as a probe molecule and were found to be produced over the irradiated SrTiO3 nanoparticles and SrTiO3-graphene composites; especially, an enhanced yield is observed for the latter. The influence of ethanol, KI, and N2 on the photocatalytic efficiency was also investigated. Based on the experimental results, ·OH, h+, and H2O2 are suggested to be the main active species in the photocatalytic degradation of AO7 by SrTiO3-graphene composites.PACS61.46. + w; 78.67.Bf; 78.66.Sq

A novel Bi4Ti3O12/Ag3PO4 heterojunction photocatalyst with enhanced photocatalytic performance

In this work, we integrated Ag3PO4 with Bi4Ti3O12 to form Bi4Ti3O12/Ag3PO4 heterojunction nanocomposites by an ion-exchange method. The as-prepared Bi4Ti3O12/Ag3PO4 composites were systematically characterized by means of XRD, SEM, TEM, BET, XPS, UV-vis DRS, EIS, PL spectroscopy, and photocurrent response. SEM, TEM, and XPS results demonstrate the creation of Bi4Ti3O12/Ag3PO4 heterojunction with obvious interfacial interaction between Bi4Ti3O12 and Ag3PO4. PL spectra, EIS spectra, and photocurrent responses reveal that the composites display an enhanced separation efficiency of photogenerated electron-hole pairs, which is due to the charge transfer between Bi4Ti3O12 and Ag3PO4. Rhodamine B (RhB) was chosen as the target organic pollutant to evaluate its degradation behavior over Bi4Ti3O12/Ag3PO4 composites under simulated sunlight irradiation. Compared to bare Bi4Ti3O12 and Ag3PO4 nanoparticles, the composites exhibit a significantly enhanced photocatalytic activity. The highest photocatalytic activity is observed for the 10% Bi4Ti3O12/Ag3PO4 composite with 10% Bi4Ti3O12 content, which is about 2.6 times higher than that of bare Ag3PO4. The photocatalytic mechanism involved was investigated and discussed in detail.

Growth process and enhanced photocatalytic performance of CuBi2O4 hierarchical microcuboids decorated with AuAg alloy nanoparticles

CuBi2O4 hierarchical microcuboids self-assembled from nanorods were synthesized via a coprecipitation method, and their growth process was investigated. The as-synthesized CuBi2O4 hierarchical microcuboids were decorated with AuAg alloy nanoparticles via a photocatalytic reduction method. The prepared samples were systematically investigated by XRD, SEM, TEM, XPS, UV–vis DRS, EIS, PL spectroscopy and photocurrent response. RhB was chosen as the target organic pollutant to evaluate the photocatalytic activity of the samples under simulated-sunlight irradiation. It is demonstrated that the prepared CuBi2O4 samples exhibit excellent photocatalytic activity toward the degradation of RhB. Furthermore, the decoration of AuAg alloy nanoparticles on CuBi2O4 hierarchical microcuboids leads to much enhanced photocatalytic performance of the resultant AuAg–CuBi2O4 composite. The main reason for this is that the recombination rate of photogenerated electron–hole pairs is decreased due to the electron transfer from CuBi2O4 microcuboids to AuAg nanoparticles, and thus more charges are able to participate in the photocatalytic reactions. The effect of ethanol (scavenger of ·OH), BQ (scavenger of

A promising supercapacitor electrode material of CuBi2O4 hierarchical microspheres synthesized via a coprecipitation route

\cdot{\text{O}}_{2}^{ - })

Morphology-controlled synthesis of orthorhombic LuFeO 3 particles via a hydrothermal route

·O2-) and AO (scavenger of h+) on the dye degradation and the yield of ·OH was also investigated. Based on the experimental results, it is confirmed that ·OH is the dominant reactive species responsible for the dye degradation. The underlying photocatalytic mechanism was discussed.

Electrochemical Performance of Morphologically Different Bi2WO6 Nanostructures Synthesized via a Hydrothermal Route

BiFeO3 microcylinders were synthesized via a hydrothermal condition. SEM observation reveals that with increasing the hydrothermal reaction time from 6 to 15 h, the microcylinders grow from ∼0.7 to ∼4.1 µm in height, whereas their diameter remains to be 3.7-3.8 µm with a minor change. The microcylinders are mainly made up of sphere-like grains of 100-150nm in size. A possible growth mechanism of the BiFeO3 microcylinders is proposed. The photocatalytic activity of the as-prepared BiFeO3 samples was evaluated by the degradation of acid orange 7 under simulated sunlight irradiation, revealing that they possess an appreciable photocatalytic activity. Magnetic hysteresis loop measurement shows that the BiFeO3 microcylinders exhibit a typical antiferromagnetic behavior at room temperature.