Study On The Dealloying Of Ti-Cu-Pd Amorphous Alloy

TiO₂, due to its stability, nontoxicity, low cost, high surface area, long-termstability, excellent catalytic activity and other advantages, has been widely used in thefelds of photolysis of water, solar cells, gas senors, air purification, photodegradationof pollutants, and specifc catalytic reactions. But as a semiconductor photocatalyst,there are two main obstacles for the practical application of TiO₂: low quantumefficiency and restriction to short wavelength excitation. To solve these problems,several kinds of modification methods have been explored and it has been shown thatmodifcation of the TiO₂surface with noble metals will be one of the most successfulways to improve its photocatalytic effciency.A newly emerging research direction that preparing nanoporous metals bydealloying methods and investigating their physical and chemical properties has beenattracted a number of scientists. Furtheremore, it is also very important to extend thefacile dealloying method to prepare other functional materials.This work is performedbased on the dealloying process.In this work, Pd doped nanoporous TiO₂was prepared by dealloying Ti-Cu-Pdamorphous alloys. The micro-structure, element and phase composition of theas-dealloyed samples were studied by FE-SEM, EDS, XPS, XRD and TEM in detail.Meanwhile, the research on the electro-catalytic and photocatalytic properties ofas-dealloyed samples was carried out in depth.The results can be listed as follows:（I） Bicontinuous nanoporous ligament-channel structures were prepared byelectrochemically dealloying Ti₃₀Cu_70-xPd_x（x=1,2,3,4,5at.%） amorphous alloys in5.36mol/L HNO3aqueous solution using a classical three-electrode setup at anappropriate potential （1.1V（.vsSCE）） for10800s. And we found that x=3is a goodporosity forming system.（II） According to the XPS analysis, the nanoporous structures are mainlycomposed of Pd, PdO, TiO, TiO₂, Ti2O3and Cu₂O.（III） Samples with nanoporous structures had good electro-catalytic propertiesfor methanol in alkaline conditions.（IV） Nanoflower-like rutile TiO₂and Pd-doped TiO₂with hierarchical structures were obtained by chemically dealloying the Ti-Cu and Ti-Cu-Pd amorphous alloys in5.36mol/L HNO3aqueous solution, respectively.（V） Both pure TiO₂powders and Pd-doped TiO₂powders prepared under thesame conditions had goog properties for the photodegradation of Rhodamine B （RhB）.And the photocatalytic activity of Pd-doped TiO₂was a bit better than that of pureTiO₂due to Pd-doped on the surface of TiO₂.