Eosin Y sensitized BiPO4 nanorods for bi-functionally enhanced visible-light-driven photocatalysis.

In this work, we report a novel photocatalyst of Eosin Y dye sensitized BiPO4 nanorods via a low-temperature and impregnation adsorption method. It shows enhanced visible-light-driven photocatalytic activity for degrading methylene blue (MB) and 2,4-DCP compared to that of pristine BiPO4 nanorods. The mass ratio of Eosin Y/BiPO4 is varied from 5 wt% to 30 wt% and the optimum value is 15 wt%, showing 46.7 and 10.5 fold greater apparent reaction rates than pristine BiPO4. Moreover, all of the reduced MB was transformed into CO2 and H2O during the photocatalysis, showing the good mineralization ability (almost 100%) of the composite. Furthermore, the photocatalytic mechanism of the composite is also investigated here by the zeta potential, scavenger experiments, Electron Paramagnetic Resonance (EPR), Photoluminescence Spectroscopy (PL), and a series of electrochemical analyses. The results show that (i) e- is the main reactive species and (ii) Eosin Y coated and adsorbed on BiPO4, thus widening the response range to the visible light region and accelerating the charge separation/transfer, resulting in bi-functionally promoted activity.

Rational shape control of porous Co3O4 assemblies derived from MOF and their structural effects on n-butanol sensing.

Porous metal oxides are promising materials for VOCs (volatile organic compounds) chemical sensors, because they have large specific surface areas and enough internal space for the fast gas diffusion. Recently, metal-organic framework (MOF) materials with varied shapes and sizes have been regarded as good templates for preparing porous metal oxides. Herein, four kinds of Co-MOFs were prepared by altering the ratios of Co2+ ions and 2-methylimidazole at room temperature, which exhibited well-controlled shapes. Then, corresponding porous Co3O4 assembled from nanoparticles was acquired by heating Co-MOFs, and showed a good sensing performance for n-butanol, with a response up to 21.0 toward 100 ppm n-butanol. Moreover, it is found that the shape and the size of Co3O4 assemblies can significantly influence their sensing performances. For porous Co3O4 assemblies, when the nanoparticles are small enough (˜10 nm), a porous structure with a larger proportion of the nanoparticles close to its surface tends to show a better gas-sensing performance. The findings can be used in the design of gas-sensing materials in the future.