Enhanced charge separation and transfer by Bi2MoO6@Bi2Mo2O9 compound using SILAR for photoelectrochemical water oxidation. (20th February 2018) - Xiong, Yuli
Abstract: The successive ionic layer absorption and reaction (SILAR) method has been successfully used for the thin film preparation of metal oxides. In this work, we firstly fabricate the hybrid Bi2 MoO6 @Bi2 Mo2 O9 photoanode by a one-step SILAR method. The optimized Bi2 MoO6 @Bi2 Mo2 O9 demonstrates a photocurrent about 0.160 mA cm −2 at 1.23 V vs. RHE, which is 3.6 and 8.0 times enhancement compared with pristine Bi2 MoO6 and Bi2 Mo2 O9 for water oxidation. The enhanced efficiencies of charge separation and oxidation kinetics by Bi2 MoO6 @Bi2 Mo2 O9 are 20.5% and 54.6% at 1.23 V vs. RHE, which is higher than Bi2 Mo2 O9 (9.2% and 15.4%) and Bi2 MoO6 (10.7% and 29.2%). Moreover, the electron transport time of Bi2 MoO6 @Bi2 Mo2 O9 is 0.038 ms at 300 W m −2 through the controlled intensity modulated photocurrent spectrometer analysis, which is lower than Bi2 Mo2 O9 (0.087 ms) and Bi2 MoO6 (0.052 ms). The enhanced photoelectrochemical activities of Bi2 MoO6 @Bi2 Mo2 O9 can be attributed to the matched energy band between Bi2 Mo2 O9 and Bi2 MoO6, which could not only improve the charge separation, but also accelerate the charge migration. Therefore, our research indicates an effective technique for fabricating Bi2 MoO6 @Bi2 Mo2 O9 by one step process, and thus may provide a new idea for the preparation of other hybrid ternary metal oxides. Graphical abstract: Highlights: Hybrid Bi2 MoO6 @Bi2 Mo2 O9 are designed and fabricated by one step SILAR method. Bi2 MoO6 @Bi2 Mo2 O9 generated 0.160 mA cm −2 for water oxidation at 1.23 V vs. RHE. The energy band of Bi2 Mo2 O9 @Bi2 MoO6 composite is beneficial for charge transfer.