Electrochemical Synthesis And Performance Research Of Metal Oxides （Co₃O₄,TiO₂） Nano-Film Materials

Electrochemical-based strategies for synthesizing metal oxides nanomaterials due to its advantages of simple and cheap apparatus, easy and flexible operation under mild condition have attracted more extensive attentions. In this thesis, we have taken CO3O4, HO2as examples to develop novel synthetic routes based on electrochemical techniques for preparing advanced metal oxides nanomaterials and characterized the performances of as-made products. The electrochemical-based routes we have developed can be used for synthesizing other metal materials due to their advantages such as mild condition and easy controlled of operation; good reproducibility, short period and high purity of products. The main research work of the thesis is list as follows:(1) Adopt Cycle Voltammograms (CV) technique oxidizing cobalt metallic layer directly in KOH electrolyte to synthesize CO3O4nano-film materials. According to FTIR, XRD, SEM and TEM characterizations, we found that the film products are composed of vertical-standing hexagonal nanosheet arrays. The average thickness and edge length of nanosheets is about20-50nm and200-500nm respectively. The as-made film electrodes as electrochemical sensor exhibit high sensitivity and electro-catalysis activity for different concentration of H2O2in solution.(2) Based on the variety and flexibility of electrochemical techniques, adopt Normal Pulse Voltammetry (NPV) technique oxidizing cobalt metallic layer in alkaline electrolyte containing ammonia to synthesize cross-linked Co3O4nanowalls materials. According to XRD, SEM and TEM characterizations, the as-made cross-linked nanowalls arrays have an edge length of up to1μm with thickness of about20nm. The electrode exhibits low oxidation over potential of about0.54V (vs. Ag/AgCl) for oxygen evolution and high exchange current density in alkaline solution which indicating an enhanced catalytic activity.(3) In alkaline electrolyte containing H2O2, adopt Ti foils as titanium source and substrates to synthesize foam-like TiO2nano-film materials based on strong oxidability and corrodibility of H2O2. According to XRD, SEM and TEM characterizations, we found that as-made TiO2nano-film materials in rutile phase with interlaced pores size5-30nm exhibit3D foam-like mesoporous architecture. The porous film electrodes demonstrate prompt photocurrent response and favorable photocurrent density in KOH electrolyte under UV irradiation.