Bi_(2)S_(3)/TiO_(2)纳米复合材料的制备及其对304不锈钢的光生阴极保护性能研究

Fabrication and Photocathodic Protection Performance of Bi_(2)S_(3)/TiO_(2) Nanocomposites for 304 Stainless Steel

通过连续离子层吸附法(SILAR)在TiO_(2)纳米管上负载Bi_(2)S_(3),通过XRD、SEM、XPS等手段对Bi_(2)S_(3)/TiO_(2)纳米复合材料的形貌、结构、元素组成和价态进行表征。同时在模拟太阳光条件下进行光电化学性能测试。Bi_(2)S_(3)改性后复合材料的带隙减小,光生载流子复合率大幅下降,当Bi_(2)S_(3)循环5次时,TiO_(2)纳米复合材料的光电化学性能最好。带隙减小到2.9 e V,光电流密度由改性前的200μA·cm^(-2)提升至550μA·cm^(-2),是改性前的2.75倍;将其与304不锈钢耦合后,电位降至-1.0 V,比改性前的耦合电位低80 m V,可以进一步提升对304不锈钢的光生阴极保护效果。

TiO_(2)nanotube arrays are decorated with Bi_(2)S_(3) by a successive ionic layer adsorption and reaction(SILAR)method,aiming to enhance the photoelectric conversion ability of TiO_(2) and photogenerated cathodic protection performance of TiO_(2)nanotube arrays for 304 stainless steel.B-(x)/TiO_(2) nanotubes(x=1,3,5,7)were prepared by changing the number of deposition cycles of Bi_(2)S_(3).The morphology,structure,light response ability and photogenerated carrier separation efficiency of Bi_(2)S_(3)/TiO_(2) nanocomposites were examined by means of XRD,SEM and XPS.At the same time,the photoelectrochemical properties of Bi_(2)S_(3)/TiO_(2) nanocomposites were tested under simulated sunlight.In addition,the effect of the number of deposition cycles of Bi_(2)S_(3) on the photocathodic protection performance of TiO_(2)nanocomposites was also studied.After Bi_(2)S_(3) modification,the band gap of the composites decreases,and the recombination rate of photogenerated carriers decreases greatly.When a 5 cyclic deposition of Bi_(2)S_(3) is adopted,the photoelectrochemical properties of the prepared nanocomposites are the best.Of which the band gap is reduced to 2.9 eV,and the photocurrent density is increased from 200μA·cm^(-2)to 550μA·cm^(-2)under the condition of turning on light,which is 2.75 times that of the bare TiO_(2) nanotube arrays.After coupling the modified nanocomposite with 304 stainless steel,the coupling potential can be reduced to-1.0 V under simulated sunlight,which is about 80 mV lower than the coupling potential before modification,which can further improve the photogenerated cathodic protection effect on 304 stainless steel.