Preparation Of Ag/Au-?-Fe 2 O 3 Heteromorphic Nanoarrays And Their Photoelectrocatalytic Properties

With the development of economy, the problem of energy and environment becomes more and more severe. The development of new resources has been the focus of scientists of the world. Hydrogen became the hot spot for its clean, high efficient and environmental interest. In this paper, we studied anode of photoelectrochemistry?PEC? cell and the catalytic performance in water splitting. One dimensional ?-Fe₂O₃ nano array was chosen as the foundational material and decorated with nano metal particles by electric method.One dimensional ?-Fe OOH nano array was synthesized on the FTO by hydrothermal method. The growth mechanism was studied. Na+ reduced the lattice mismatch between ?-FeOOH and SnO2 and Cl- promoted the axial growth. The effect of substrate, reactant concentration, reaction temperature and pH value were also discussed. The ?-FeOOH was transformed to ?-Fe₂O₃ by annealing.Ag particles were deposited on the surfaces of the ?-Fe₂O₃ nanorods. The effects of potential and treating time on the size and distribution were discussed. Ag nano particles with size of 30-50 nm were obtained when the potential is-1.2 V and the time is 150 s. The optics and catalysis property were tested to analyze the effect of Ag on the nanoarrays' property. The current density of Ag-?-Fe₂O₃ was 0.075 mAcm-2 at 0.45 V which is 6 times of pure ?-Fe₂O₃. The initial reaction potential was 0.35 V which is 200 mV lower than the pure ?-Fe₂O₃.Au particles were deposited on the surfaces of the ?-Fe₂O₃ nanorods by step potential method. The effects of potential and treating time on the size and distribution were discussed. Au nano particles with size of 50-80 nm were obtained when the potential is-1.4 V, 2 s and-1.2 V, 50 s. The optics and catalysis property were tested to analyze the effect of Au on the nanoarrays' property. The current density of Au-?-Fe₂O₃ was 0.25 mAcm-2 at 0.45 V which is about 20 times of pure ?-Fe₂O₃. The initial reaction potential was 0.25 V which is about 300 mV lower than the pure ?-Fe₂O₃.One dimension structure provided a fast way to the electron. Metal particles with nano size had big optical section and enforced the light absorbency. Au and Ag had surface Plasmon resonance effect and changed the energy field on the electrode surfaces. The electron- hole recombination was reduced. After decoration with Ag and Au, the optic and catalysis property were improved.