Construction of a Z-scheme heterojunction bifunctional photocatalyst with Ag-modified AgBr embedded in ß-Bi2O3 flowers.

ß-Bi2O3 demonstrates excellent photocatalytic activity under visible light, but it has a very high photogenerated e--h+ recombination rate and quite low quantum efficiency. AgBr also shows excellent catalytic activity but Ag+ is easily reduced to Ag under light radiation, which limits its application in the photocatalysis field, and there are few reports about the application of AgBr in photocatalysis. In this study, the spherical flower-like porous ß-Bi2O3 matrix was first obtained, and then the spherical-like AgBr was embedded between the petals of the flower-like structure to avoid direct light radiation. The only light through the pores on the ß-Bi2O3 petals could be transmitted onto the surfaces of AgBr particles to form a nanometer point light source, which photo-reduced Ag+ on the surface of the AgBr nanospheres to construct the Ag-modified AgBr/ß-Bi2O3 embedded composite and a typical Z-scheme heterojunction was constructed. Under this bifunctional photocatalyst and visible light, the RhB degradation rate reached 99.85% in 30 min, and the photolysis water hydrogen production rate reached 6.288 mmol g-1 h-1. This work is as an effective method for not only the preparation of the embedded structure, quantum dot modification and flower-like morphology but also for the construction of Z-scheme heterostructures.

Preparation of Bitter Melon-like Ordered Porous Fluorinated Eu3+-Phenanthroline/ZnO Composite with Yellow Light Emission.

The soft template method was used to synthesize the ordered porous ZnO precursor and with 1,10-phenanthroline as an organic ligand, Eu3+ as a luminescent center ion, and NH4F as a fluorine source, a kind of much uniform bitter melon-like ordered porous fluorinated Eu3+-phenanthroline/ZnO composite was finally prepared through the hydrothermal method. The average length of the bitter melon-like particles was 0.7-1.0 µm, and its average diameter was 300-400 nm, which had a lot of ordered mesoporous dispersed on the surfaces. The prepared materials showed strong yellow and blue light emission under 394 and 275 nm excitation, respectively. The optimum synthesized conditions were determined according to the synthesis parameter of the sample with the strongest emission peak intensity.

Synthesis of Ordered Mesoporous ZnO Nanostructures for Gas Sensing.

In this study, the ordered mesoporous jar structure ZnO particles have been synthesized by template method. The cetyltrimethylammonium bromide (CTMAB) was used as the template agent, and zinc acetate dihydrate was used as zinc sources. The prepared material has ordered mesoporous on the surface. The prepared ordered mesoporous ZnO particles showed the hexagonal prisms hollow jar structure, the hexagonal prisms average diameter was about 150 nm, the average length was about 200 nm, and the jar average diameter was about 100 nm. The prepared materials were used as a gas sensor to test the toxic gas. The ordered mesoporous ZnO material showed more excellent gas sensing performances than the imporous ZnO material which was prepared without template agent by the same method. In particular, the ordered mesoporous ZnO showed a higher response to NOx, the detection limit reached to 0.5 ppm, the sensitivity reached to 66.92, and the response time was 1.08 s to 100 ppm NOx at 193 °C. The prepared material will be an excellent gas sensing matrix materials, and have a wide application prospect in gas sensors field.

Study on room temperature gas-sensing performance of CuO film-decorated ordered porous ZnO composite by In2O3 sensitization.

For the first time, ordered mesoporous ZnO nanoparticles have been synthesized by a template method. The electroplating after chemical plating method was creatively used to form copper film on the surface of the prepared ZnO, and then a CuO film-decorated ordered porous ZnO composite (CuO/ZnO) was obtained by a high-temperature oxidation method. In2O3 was loaded into the prepared CuO film-ZnO by an ultrasonic-assisted method to sensitize the room temperature gas-sensing performance of the prepared CuO/ZnO materials. The doped In2O3 could effectively improve the gas-sensing properties of the prepared materials to nitrogen oxides (NO x ) at room temperature. The 1% In2O3 doped CuO/ZnO sample (1 wt% In2O3-CuO/ZnO) showed the best gas-sensing properties whose response to 100 ppm NO x reached 82%, and the detectable minimum concentration reached 1 ppm at room temperature. The prepared materials had a good selectivity, better response, very low detection limit, and high sensitivity to NO x gas at room temperature, which would have a great development space in the gas sensor field and a great research value.