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采用焙烧前驱物碱式碳酸锌的方法制备了不同粒径的ZnO纳米粒子 ,而用粒径最小的作为光催化剂 ,通过光还原过程分别得到了贵金属质量分数为 0 .5 %和 0 .75 %的Pd/ZnO或Ag/ZnO复合纳米粒子 .利用XRD ,TEM ,XPS ,SPS和EFISPS等测试技术对样品进行了表征 ,并通过光催化氧化气相正庚烷评估了样品的光催化活性 ,考察了微晶尺寸和贵金属Pd或Ag的沉积对ZnO纳米粒子表面光电压信号以及光催化活性的影响 ,探讨了样品表面光电压谱与其光催化活性的关系 ,说明了可以通过表面光电压谱的测试来初步地评估纳米粒子的光催化活性 .结果表明 :随着ZnO纳米微晶尺寸的减小 ,其SPS信号强度逐渐变弱 ,而光催化活性逐渐升高 ;沉积适量的贵金属Pd或Ag后 ,ZnO纳米粒子的SPS信号强度明显下降 ,而其光催化活性却有所升高 .此外 ,对ZnO纳米粒子光催化剂的失活机理进行了分析
ZnO nanoparticles with different particle sizes were prepared by calcining the precursor of basic zinc carbonate, while the smallest particle size was used as the photocatalyst, the mass fraction of noble metal was 0.5% and 0.75% Of Pd / ZnO or Ag / ZnO nanocomposites.The samples were characterized by XRD, TEM, XPS, SPS and EFISPS and their photocatalytic activities were evaluated by photocatalytic oxidation of n-heptane in the gas phase. Crystallite size and the deposition of noble metal Pd or Ag on the surface photovoltage signal and photocatalytic activity of ZnO nanoparticles. The relationship between the surface photovoltage spectra and the photocatalytic activity of ZnO nanoparticles was discussed. It is demonstrated that the surface photovoltage spectra can be preliminarily evaluated by surface photovoltage spectroscopy The results showed that the SPS signal intensity gradually weakened and the photocatalytic activity increased with the decrease of the size of ZnO nanocrystallites. After depositing the appropriate amount of Pd or Ag, the size of ZnO nanoparticle SPS signal intensity decreased significantly, but its photocatalytic activity has increased.In addition, the deactivation mechanism of ZnO nanoparticles photocatalyst was analyzed