Multiple layered macroporous SnO2 film for applications to photoelectrochemistry and morphology control of iron oxide nanocrystals

Multiple layered ordered macroporous SnO2 (mac-SnO2) electrode is homogeneously decorated with cc-Fe2O3 photocatalyst as a photoanode for solar energy conversion. The as-prepared mac-SnO2 electrodes are coated with alpha-Fe2O3 via typical hydrothermal method with varied conditions to manipulate the nanostructure of alpha-Fe2O3@ mac-SnO2. In comparison to a planar substrate, smaller alpha-Fe2O3 nanocrystals are obtained on mac-SnO2, and the size of coated alpha-Fe2O3 is contained at a certain scale disregarding the synthetic conditions. The optimized alpha-Fe2O3@mac-SnO2 electrode exhibits a maximum photocurrent density of 1.71 mA cm(-2) at 0 V vs. V-Ag/(Agcl), and 2.41 mA cm(-2) at 1.23 V vs. V in 1 M NaOH aqueous electrolyte under visible light irradiation. The improved photocurrent density can be attributed to the greater surface area by mac-SnO2 film, enhanced light absorption and the optimized nanostructure of alpha-Fe2O3@mac-SnO2. In addition to the photoelectrochemical performance, the application of mac-structural materials to control the morphology of nanocrystals is also investigated.