Fine Chemical Synthesis on Metal Nanoparticle Photocatalysts

负载金属纳米粒子的光催化剂实现了高效和选择性的光催化反应。我们阐明了几个反应，如仲胺的合成从醇和硝基芳烃，芳族卤化物的脱卤，和过氧化氢的生产由负载Pd，Pt-Pd合金，和Au-Ag合金纳米粒子的催化剂。特别地，我们发现，当负载在二氧化钛上时，Au或Pt纳米颗粒通过颗粒吸收可见光，然后将激发的电子转移到半导体导带来促进有效的有氧氧化。此外，负载Au-Cu合金颗粒有效地促进有氧氧化，但活性随着表面Cu原子的氧化而降低。我们发现，可见光照射通过Au原子的可见光吸收成功地还原了氧化的表面Cu，从而保持了高的氧化活性。

Efficient and selective photocatalytic reactions have been achieved with the photocatalysts loaded with metal nanoparticles. We clarified that several reactions such as secondary amine synthesis from alcohol and nitroaromatics, dehalogenation of aromatic halides, and hydrogen peroxide production by the catalysts loaded with Pd, Pt-Pd alloy, and Au-Ag alloy nanoparticles. In particular, we found that Au or Pt nanoparticles when loaded on titanium dioxide promotes efficient aerobic oxidation via the absorption of visible light by the particles followed by the transfer of excited electrons to semiconductor conduction band. In addition, supported Au-Cu alloy particles efficiently promote aerobic oxidation, although the activity decreases with by the oxidation of surface Cu atoms. We found that visible light irradiation successfully reduces the oxidized surface Cu via the visible light absorption by Au atoms, thus maintaining high oxidation activity.