No abstract

In this paper, g-Bi 2 O 3 , considered as the best photocatalyst among all Bi 2 O 3 polymorphs, was successfully prepared on the surface of m-BiVO 4 octahedral crystals through an alkaline "etching" process. Extensive XRD, SEM and TEM characterization revealed the formation of a p-n junction in the form of m-BiVO 4 @g-Bi 2 O 3 core-shell heterostructure. In addition, the alkaline concentration and reaction time during the etching process were studied and found to be critical parameters in the formation and yield of the Bi 2 O 3 phase. The visible-light photocatalytic activities of these heterogeneous samples with different g-Bi 2 O 3 /m-BiVO 4 phase ratios were evaluated for the degradation of Rhodamine B (RhB). The results indicated that with an optimum amount of g-Bi 2 O 3 on the m-BiVO 4 surface, the powders showed superior photocatalytic performance over pure m-BiVO 4 octahedral crystals. The enhancement mechanisms were discussed based on the specific surface area and g-Bi 2 O 3 shell thickness, as well as the influences of improved charge carrier transfer on the p-n heterostructure.

No abstract

No abstract

No abstract

In this Article, the improvement in the conversion efficiencies of dye-sensitized solar cells (DSSCs) was observed by integrating a small amount of thermally oxidized titanium nitride (TiN x O y ) particles into the hydrothermally growth TiO2 nanoparticles to form the composite photoanode. The oxidation of titanium nitride (TiN) to TiN x O y (N-doped TiO2) was achieved using a simple single-step annealing process at 450 °C for 1 h. The existence of the O–Ti–N linkage in TiN x O y was verified using X-ray photoemission spectroscopy (XPS). The DSSCs using the composite photoanode with 5 wt % of TiN x O y particles in TiO2 showed optimum conversion efficiency with a 25.6% improvement over the conventional DSSCs using only the mesoporous TiO2 layer as photoanode. Higher incident photon-current conversion efficiency (IPCE) values were also obtained for these composite photoanodes. This marked improvement was attributed to the combined synergetic effects of an extra absorption in the visible region and an enhanced efficiency in the electron transport. The extra absorption region at 400–500 nm for TiN x O y was observed using a UV–vis spectrophotometer. In addition, the reduction of charge transport resistance in the composite photoanode as verified using electrochemical impedance spectroscopy (EIS) has also contributed to faster electron transport through the interpenetrating oxide layer.

No abstract

No abstract