| Environmental pollution and energy crisis are two of the most serious problems facing humanity today. As a new research issue, photocatalytic technology provides a possible route to solve the environmental pollution and energy crisis. The photocatalytic technology shows great potential for the removal of organic pollutants and water splitting. However, the narrow light response range and the recombination of photo-generated electrons and holes are prevailing problem of the photocatalyst, resulting in low photocatalytic efficiency. In recent years, a new type of surface plasmonic photocatalyst has been developed due to its enhanced light absorption, which can promote the separation of photogenerated charge so as to improve the photocatalytic efficiency. This type of surface plasmonic photocatalyst is mainly about noble metal loaded onto semiconductor or other supports(active carbon, graphene, fiber). However,noble metal photocatalysts without any semiconductor/molecular photocatalysts are rarely reported. In addition, ion doping is an important method for the modification of semiconductor photocatalyst, and the photocatalytic activity of semiconductor photocatalyst can be enhanced by ion doping. In this dissertation, we focus on the research of surface plasmonic photocatalytic hydrogen production performance of metal nanoparticles, and tuning the bandgap of semiconductor by ion doping to improve the photocatalytic properties. The main points of this thesis are summarized as follows:(1) The copper nanoparticles with different diameters were synthesized by various methods, and the photocatalytic activities for hydrogen evolution were evalutaed. CuNPs formed in-situ by photolysis can reach an average rate of 35 mmol?g-1?h-1 under irradiation for hydrogen production, using lactic acid as a sacrificial electron donor. Moreover, the photocatalyst can be recycled for further use with persistent photocatalytic efficiency even after five cycles of testing. Using C60 as a co-catalyst, hydrogen production rate reached 54.58mmol?g-1?h-1.(2) A new type of photocatalysis system that can generate H2 from water under irradiation has been described. AgNPs were synthesized successfully via a facile photo-reduction method exhibiting an admirable photocatalytic activity with the average hydrogen evolution rate of 20 mmol?g-1?h-1, using triethanolamine as a sacrificial electron donor and without the use of semiconductors. The photocatalytic activity of AgNPs can be attributed to the LSPR effect. The surface plasmon photocatalytic mechanism of silver nanoparticles was verified by the design of Ag NPs core/shell structure of PVP insulation layer. Using C60 as a co-catalyst, the hydrogen production rate of C60-AgNPs is 2.6 times that of AgNPs.(3) Cerium and antimony co-doped tin dioxide(Ce/ATO) nanostructured particles(Nps) were prepared by sol-gel method. X-ray diffraction, field emission scanning electron microscopy, Uv–Vis spectrophotometer, fluorescence spectrophotometer and X-ray photoelectron spectroscopy were employed to characterize the structure, morphology, optical properties and element valence state. The results show that the Ce/ATO exhibited photocatalytic ability for hydrogen production in a lactic acid solution. 4mol%Ce/ATO showed the highest rate of hydrogen production(8.5 μmol?g-1?h-1) among the samples at different doping concetrations under light irradiation. It demonstratesthat the doping of Ce can tune the band gaps of ATO samples and minimize the recombination of electron–holes in the Ce/ATO sample which can improve the photocatalytic activity. |
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