Preparation Of Titanium-based TiO₂ Nanosheets And Research On Photoelectrocatalytic Degradation Of Environmental Drugs

Photocatalytic oxidation of TiO₂ semiconductor has been regarded as one of the most promising techniques for removal of environment pollutants by using solar energy.The work on the photocatalytic elimination of organic pollutants from sewage has become a growing field.In this dissertation,two types of photoelectrodes based on the well-organized TiO₂ BNSs were prepared by the adulteration and modification.Meanwhile,the physicochemical performances,photoelectrochemical properties and photoelectrocatalytic activities of the as-prepared TiO₂ BNSs photoelectrodes were detailedly investigated.The well-organized of TiO₂ BNSs photoelectrode was prepared directly growth of TiO₂ BNSs onto the Ti substrate through hydrothermal procedure.Subsequently,the effects of synthesis parameters on the apparent morphologies and photocatalytic removal efficiency of methyl orange of TiO₂ BNSs photoelectrode were analyzed in detail.Results revealed that the optimized concentration of NaOH,hydrothermal temperature,hydrothermal time,concentration of HCl,acid-washing time and post-calcinating temperature were 1 mol/L,170?,28 h,0.1 mol/L,24 h,500?,respectively.Under the optimized conditions,the as-prepared TiO₂ BNSs photoelectrode exhibited the greatest photocurrent density,open circuit voltage and photoelectrocatalytic efficiency.The 77.8%of photocatalytic efficiency and the 89.8%of photoelectrocatalytic efficiency for the degradation of aspirin of 5 mg/L could be obtained within 90 min.Besides,·OH was the crucial oxidative specie s during the photoelectrocatalytic process.The C,N and S codoped TiO₂ BNSs?C-N-S-TiO₂ BNSs?photoelectrode was prepared via simple one-step hydrothermal procedure,and several pivotal synthesis parameters were systematically investigated.It was found that the optimized additive concentration of cystine was 0.01 mol/L.Codoped C,N and S could enhance the visible absorption ability and separation efficiency of photogenerated charge carriers of the TiO₂ BNSs photoelectrode.In addition,under the optimized conditions,the 59.7%of photocatalytic efficiency and the 77.2%of photoelectrocatalytic efficiency for the degradation of aspirin of 10 mg/L could be obtained within 2 h over the C-N-S-TiO₂BNSs photoelectrode.And the photocatalytic and photoelectrocatalytic degradation rate of aspirin was 43.5%and 62.4%,respectively,when TiO₂ BNSs was used as the photoelectrode.The Pd/C-N-S-TiO₂ BNSs photoelectrode was fabricated through hydrothermal treatment,followed by photodeposition strategy.Results showed that the optimized concentration of PdCl₂ solution and photodeposition time were 2.0×10^-4 mol/L and 60min,respectively.And the chemical state of Pd was mainly Pd⁰ nano-particle.The photocurrent density,open circuit voltage,visible absorption ability and yield of·OH of C-N-S-TiO₂ BNSs photoelectrode were markedly improved by deposition with Pd⁰nano-particle,thereby resulting in an enhanced photoelectrocatalytic property.The photoelectrocatalytic removal efficiency of cefuroxime sodium of 10 mg/L for 2 h reaction was 73.1%when the constructed Pd/C-N-S-TiO₂ BNSs photoelectrode was used.Under the same conditions,the photoelectrocatalytic degradation rate of C-N-S-TiO₂ BNSs,Pd/TiO₂ BNSs and TiO₂ BNSs photoelectrode were 66.4%,62.2%and 56.3%,respectively.Furthermore,the degradation reaction fitted the pseudo-first-order kinetics according to the Langmuir-Hinshelwood model.