Pt修饰TiO_2纳米管的接触势与光电性能

Contact Potential Barriers and Photoelectric Properties of Pt-TiO_2 Nanotubes

采用碱熔-水热法在常压下制备了Pt修饰TiO_2复合纳米管(Pt-TNT),并对其微观组织形貌和性能进行了表征.结果表明,Pt-TNT主要由锐钛矿相和金红石相TiO_2组成,铂和氧化铂(Pt,PtO,PtO_2,记作PtO_x^(δ+))分散在TiO_2纳米管表面.Pt-TNT表面接触势为PtO_x^(δ+)-锐钛矿-金红石-PtO_x^(δ+)类型,Pt-TNT比表面积(BET)由原料的9.0 m^2/g增至41 m^2/g,增加3.55倍.傅里叶变换红外(FTIR)光谱中1047与1641 cm^(-1)处的OH弯曲振动峰是由Pt-TNT样品表面吸附δ-H_2O所致.表面光电压分析显示TiO_2表面光伏响应红移,在外电场作用下深能级上的束缚激子由带-带跃迁变为亚带隙跃迁.

Composite TiO2 nanotubes of Pt-modified（Pt-TNT） were synthesized via alkaline fusion-hydrothermal method under ambient atmosphere pressure. The microstructure morphology and properties of Pt-TNT were characterized. Composition analysis showed that the particulate matters on surface of Pt-TNT were composed of platinum and platinum oxides（Pt,PtO and PtO2,PtOx（δ＋））. Contact potential barriers consisting of PtOx（δ＋）anatase-rutile-PtOx（δ＋）are presumed to form upon PtOx（δ＋）particle that deposited on the surface of Pt-TNT. The result of XRD indicated that a mixture of anatase and rutile phases prevailed in Pt-TNT. The 1047 and 1641 cm（-1）（OH bending vibration） of FTIR were caused by the adsorption of δ-H2O on the surface of Pt-TNT.Surface photovoltage spectroscopy（SPS） and electric field-induced surface photovoltage spectroscopy（FISPS）demonstrated that the bound exciton which showed sub-band gap transition characteristics with the asymmetric changes of photoelectric property corresponding to changes in polarity and strength of the external electric field.Compared with TiO2,BET of Pt-TNT increased more than 3. 55 times and was 41 m2/g by nitrogen adsorption.