Fabrication And Electrocatalytic Properties Of Graphene And TiO₂ Nanotubes

This work introduces two Ti-based hybrid electrodes including TiO₂/Ti electrode and graphene/TiC nanorod array electrode,and the properties of both are investigated respectively.First,Au nanoparticles and TiO₂ nanotube hybrid materials were prepared electrochemically.The Ti wire was used to form TiO₂ nanotube arrays via anodization and subsequent annealing process.The Au nanoparticles were then electrodeposited in chloroauric acid solution to form Au/TiO₂ hybrid layers.These two steps were repeated to prepare Au/TiO₂,TiO₂/Au/TiO₂ and Au/TiO₂/Au/TiO₂ hybrid materials,and the morphology,structure and formation of nanocomposite is discussed.The Au/TiO₂ hybrid materials also exhibited different photoelectrocatalytic activities for decomposing methyl orange.The application of the Au/TiO₂/Au/TiO₂ hybrid material as a photo-anode has been simultaneously examined toward electrochemical–oxidation,photo-oxidation,and photoelectro-oxidation of methyl orange.The photoelectrocatalytic mechanism of Au/TiO₂/Au/TiO₂ hybrid material and its degradation reaction mechanism for methyl orange were evaluated.Second,vertically stacked graphene nanosheet/titanium carbide nanorod array/titanium wires electrode were fabricated using a direct current arc plasma jet chemical vapor deposition method.The graphene/TiC nanorod arrays electrode were characterized by scanning with electron microscopy,transmission electron microscopy,Raman spectroscopy,X-ray photoelectron spectroscopy,and X-ray diffraction spectroscopy.The TiO₂ nanotube array was reduced to the TiC nanorod array,and using those nanorods as nucleation sites,the vertical graphene layer was formed on the TiC nanorod surface.The multi-target response mechanisms of the graphene/TiC nanorod array were investigated for ascorbic acid?AA?,dopamine?DA?,uric acid?UA?,and hydrochlorothiazide?HCTZ?.The linear range of four substances is 3-600,0.3-8 and 8-60,0.3-8 and 8-60,0.3-8 and 8-60?M.The graphene/TiC nanorod arrays electrode provided high selectivity with a detection limit of 1 mM for AA,0.1 mM for DA,0.1 mM for UA,and 0.2 mM for HCTZ,having good application foreground in the fields of biosensor.The electron cloud distribution of HOMO and LUMO,the energy gap of analytes,and the work function of graphene were determined to be the response mechanisms.Thus,the graphene/TiC nanorod arrays could simultaneously respond to trace biomarkers and antihypertensive drugs.The innovation point of this paper : First,The composite materials photo-anode ofAu nano particle and TiO₂ nanotube having a higher capacity of photoelectron-catalysis was designed.Second,The TiC nanorod array taking TiO₂ nanotube array as a template was prepared.Accordingly,the composite multiple target sensor of vertical grapheme and TiC nanorod array was builded.