Photocatalysis Enhancement Of Au/BFO Nanocomposite Using Plasmon Resonance Of Au NPs

With the increasing global concern over organic pollution these years, many effective measures have been taken for degradation of organic pollutants, such as utilizing heterogeneous photocatalyst especially those capable of responding to visible light which is the main component of the solar spectrum. Since titanium dioxide was discovered as a best catalyst for degrading organic molecules without second pollution, plenty of experiments concerned were conducted to improve the photo catalysis behavior. While TiO2 with the high band gap (3.2eV) only responds to ultraviolet light. As we know, a relatively small amount of UV light in sunlight can be harnessed to meet the needs of photocatalysts responding to only UV light. But BiFeO3 nanoparticles as a photocatalyst have moderate band gap (2.1 eV-2.7 eV), so the absorption spectra is in the visible light region (400 nm-700 nm).Normally, the main factors that affect catalytic activity include the quantity of electron-hole pairs, and the recombination rate of electron-hole pairs. The photocatalytic activity of BiFeO3 nanoparticles is also constrained by such factors as mentioned above. The ways to decorate photocatalysts include preparation of photocatalyst in composite structure, metal doping, nonmetallic elements doping and the deposition of noble metal. With the addition of noble metal such as gold or silver, the photocatalytic activity was improved remarkably for the surface plasmon resonance of Au or Ag nanoparticles (NPs). In this paper, the Au NPs could be successfully deposited on the BiFeO3 particles vis impregnation-reduction method, The enhanced local electric field induced by the SPR of Au NPs will result in the more electrons and holes in the BiFeO3.Further experiments showed that the catalytic activity was enhanced more remarkbly with the increase of Au loadings in Au/BiFeO3 nanocomposites, but the organic degradation by Au/BiFeO3 nanoparticles was significantly suppressed for the excessive Au NPs. Therefore, our study focuses on determining the optimum Au loading content and explaining the key role of Au NPs in the photo-catalytic reaction.