Enhanced charge separation and transfer by Bi2MoO6@Bi2Mo2O9 compound using SILAR for photoelectrochemical water oxidation

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 Bi 2 MoO 6 @Bi 2 Mo 2 O 9 photoanode by a one-step SILAR method. The optimized Bi 2 MoO 6 @Bi 2 Mo 2 O 9 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 Bi 2 MoO 6 and Bi 2 Mo 2 O 9 for water oxidation . The enhanced efficiencies of charge separation and oxidation kinetics by Bi 2 MoO 6 @Bi 2 Mo 2 O 9 are 20.5% and 54.6% at 1.23 V vs. RHE, which is higher than Bi 2 Mo 2 O 9 (9.2% and 15.4%) and Bi 2 MoO 6 (10.7% and 29.2%). Moreover, the electron transport time of Bi 2 MoO 6 @Bi 2 Mo 2 O 9 is 0.038 ms at 300 W m −2 through the controlled intensity modulated photocurrent spectrometer analysis, which is lower than Bi 2 Mo 2 O 9 (0.087 ms) and Bi 2 MoO 6 (0.052 ms). The enhanced photoelectrochemical activities of Bi 2 MoO 6 @Bi 2 Mo 2 O 9 can be attributed to the matched energy band between Bi 2 Mo 2 O 9 and Bi 2 MoO 6 , which could not only improve the charge separation, but also accelerate the charge migration. Therefore, our research indicates an effective technique for fabricating Bi 2 MoO 6 @Bi 2 Mo 2 O 9 by one step process, and thus may provide a new idea for the preparation of other hybrid ternary metal oxides.