Plasma Enhanced Wet Chemical Surface Activation of Ti[O.sub.2] for the Synthesis of High Performance Photocatalytic Au/Ti[O.sub.2] Nanocomposites

To enhance the effectiveness of Ti[O.sub.2] as a photocatalyst, it was believed that the drawbacks of the large bandgap and the rapid electron-hole recombination can be overcome by coupling Ti[O.sub.2] with plasmonic metal nanoparticles. The incorporation of the nanoparticles onto the Ti[O.sub.2] surface requires a suitable procedure to achieve the proper particle adhesion. In this work, we propose a simple, clean, and effective surface activation of Ti[O.sub.2] using plasma enhanced wet chemical surface treatment. Under only 5 min of plasma treatment in a 3% N[H.sub.3]/3% [H.sub.2][O.sub.2] solution, gold nanoparticles were found better adhered onto the Ti[O.sub.2] surface. Hence, the methylene blue degradation rate of the Au/Ti[O.sub.2] under sunlight treated was improved by a factor of 3.25 times in comparison to non-treated Au/Ti[O.sub.2] and by 13 times in comparison to the bare rutile Ti[O.sub.2]. Keywords: plasma-liquid interaction; sunlight degradation; Au/Ti[O.sub.2] nanocomposite; surface treatment; noble metal based photocatalyst