Fabrication Of Modified TiO₂ Nanorods/Nanosheets Photoelectrode And Its Visible Light Photocatalytic Degradation Of Ibuprofen In Water

Emerging contaminants were frequently detected in municipal water plants,which brought great harm to human beings and the environment.However,pristine pulverous TiO₂ photocatalytic technology had some deficiencies including low visible light absorption efficiency and difficulty of recycle and reuse in suspension solution,which severely limited the application of TiO₂photocatalytic technology in practical production.Therefore,in this paper,several photoelectrodes based on the immobilized TiO₂ nanorods/nanosheets?TiO₂ NRs/NSs?were fabricated by modification with self-doping,AgBr nano-cakes,and MS?M=Bi,Sn?nano-particle.Meanwhile,physicochemicalproperties,photoelectrochemical?PECH?performancesand photoelectrocatalytic?PC?activities of the modified TiO₂ NRs/NSs photoelectrodes were systematically investigated.Based on the above contents,the main works of this paper are as follows.In order to study the effect of microstructure on photocatalytic performance of TiO₂photocatalyst,thus,the fixed TiO₂ NRs/NSs photoelectrodes have been fabricated by regulating the hydrothermal time,hydrothermal temperature,concentration of NaOH,pickling conditions and calcination temperature.The optimal synthesis parameters for TiO₂ NRs/NSs photoelectrode was determined,that is,the hydrothermal time is 16 h,the hydrothermal temperature is 200?,hydrochloric acid is used as the pickling agent and the calcination temperature is 500?for 2 h.Meanwhile,the best photocatalytic efficiency for the degradation of methylene blue?MB?by TiO₂NRs/NSs photoelectrode was 73.56%within 150 min under 35 W Xenon light irradiation.Moreover,the prepared TiO₂ NRs/NSs photoelectrode under optimal conditions exhibit outstanding UV-visible absorption capacity and photoelectrochemical properties.In order to improve the deficiencies of the low visible light utilization and high recombination rate of photogenerated carriers,Ti³⁺self-doped(Ti³⁺/TiO₂ NRs/NSs)AgBr nano-cakes decorated TiO₂ NRs/NSs photoelectrode(AgBr-Ti³⁺/TiO₂ NRs/NSs)has been successfully fabricated through solution reduction treatment,followed by successive ionic layer adsorption and reaction?SILAR?strategy.Subsequently,various characterization techniques were applied to study the physical and chemical properties of AgBr-Ti³⁺/TiO₂ NRs/NSs photoelectrode.The results showed that when the concentration of NaBH₄ solution was 1.5 mol·L^-1 and the reduction time was 24 h the prepared Ti³⁺/TiO₂ NRs/NSs shows the optimal PC activity for photocatalytic degradation of MB.An 89.61%of photocatalytic efficiency for the degradation of methylene blue could be achieved.After 150 min of illumination,the photocatalytic degradation efficiency of Ti³⁺/TiO₂ NRs/NSs was 89.61%.When the number of cycles was 4 and the impregnation time was 1 min,the optimum photocatalytic degradation efficiency of MB by AgBr-Ti³⁺/TiO₂ NRs/NSs photoelectrode was 98.7%.In addition,the photocurrent density,carrier concentration and photocatalytic activity of TiO₂ NRs/NSs photoelectrode were significantly improved after modification with Ti³⁺self-doped and AgBr nano-cakes.The photocatalytic performance of TiO₂ NRs/NSs photoelectrode can be further improved by semiconductor coupling.Therefore,MS?M=Bi,Sn?nano-particles decorated TiO₂ NRs/NSs photoelectrode has been successfully fabricated in this paper.The results showed that when the concentration of bismuth nitrate and sodium sulfide was 0.01mol·L^-1,and the dipping frequency and time was 4 times and 1 min,respectively,the average size of the prepared Bi₂S₃ nanoparticles is 25 nm.The Bi₂S₃ nanoparticle distribute evenly on the surface of TiO₂ NRs/NSs photoelectrode.In addition,after modification of SnS nanoparticles,the photochemical conversion efficiency,the carrier lifetime,charge layer thickness,separation efficiency of carrier and photocatalytic activity of TiO₂ NRs/NSs photoelectrode were significantly increased.After irradiation for 150 min,the photocatalytic degradation efficiency of MB by SnS/TiO₂ NRs/NSs photoelectrode was 96.3%,which increased by 23%compared with that of pure TiO₂ NRs/NSs photoelectrode.Emerging contaminants,such as ibuprofen in aquatic environment,was selected and served as the target contaminant to study the photocatalytic performances of the as-modified TiO₂NRs/NSs photoelectrode under visible light irradiation.Moreover,the photocatalytic degradation ability of IBU over SnS/TiO₂ photoelectrode was investigated by the removal rate of TOC.The influence factors of photocatalytic degradation of IBU and the kinetics characteristics were further interpreted.The results show that the modified TiO₂ NRs/NSs photoelectrode exhibits good photocatalytic degradation activities for IBU,and the degradation process conforms to the quasi-first-order reaction kinetics model.Among them,SnS/TiO₂ NRs/NSs photoelectrode showed the best photocatalytic TOC removal efficiency.After 180 min,the TOC removal rate on photocatalytic degradation of IBU was 72%under 35 W xenon lamp exposures,and the rate constant was 0.00652 min^-1.Moreover,we investigated the effects of different factors?common negative ions,initial IBU concentration and initial pH of IBU solution?on photocatalytic degradation of IBU.After four cycles,SnS/TiO₂ NRs/NSs photoelectrode still exhibits an excellent photocatalytic degradation efficiency of IBU.