采用溶胶-水热法直接获得表面修饰十二烷基苯磺酸钠(DBS)分子基团的TiO2纳米粒子,并考察了DBS表面修饰对纳米TiO2光催化氧化降解气相n-C5H12反应的活性和寿命的影响,并利用表面光电压(SPS)谱和光致发光(PL)光谱等方法研究了DBS表面修饰的影响机制.结果表明,表面修饰DBS分子基团能够抑制TiO2纳米微晶生长,促进纳米TiO2分散,增强吸附性和提高光生电荷分离,使光催化活性显著提高.但寿命并未下降,这与TiO2和DBS基团的光稳定性有关.动力学研究结果表明,TiO2光催化氧化n-C5H12反应遵循Langmuir—Hinshelwood动力学模型,为准一级反应.
Sodium dodecylbenzenesulfonate groups(DBS)-modified TiO2 nanoparticles were directly prepared by a sol hydrothermal method, the effects of DBS modification on photocatalytic performance, including mainly activity and lifetime, of nanosized TiO2 in the degradation of gaseous n-C5H12were studied, together with the affecting mechanism of DBS modification by means of surface photovoltage spectroscopy(SPS) and photoluminescence(PL). The results show that the modification with DBS molecule groups can inhibit the crystallite growth, improve particle dispersibility, enhance the capability to adsorb organic substance, and increase separation rate of photoinduced charges, which are responsible for the increase in the photocatalytic activity. Interestingly, the lifetime of the surface-modified photocatalyst does not decrease, compared with that of unmodified sample, demonstrating that DBS groups are relatively stable. In addition, the photocatalytic reaction of gaseous n-C5H12 on TiO2 follows a Langmuir-Hinshelwood model, and also is a pseudo-first order reaction.