Controlled Synthesis Of Au/?-? Semiconductor Hetero-nanocrystals And Their Photocatalytic Properties Research

Hetero-nanostructures consist of Au and ?-? semiconductor own broad scientific research and application value in photovoltaic cell,photocatalytic water splitting,light emitting LED and efficient luminescence fields due to their unique optical and electrical properties and coupling.In this paper,we focused on the core-shell and yolk-shell nanostructures formed by Au and ?-? semiconductor,by the combination of non-epitaxial growth method and ion exchange method,precisely controlled Au@XS(X presents Zn,Cd)hetero-nanocrystals can be achieved.Their photocatalytic activities,including methylene blue degradation,photocatalytic hydrogen evolution and the difference of hetero-interface caused interaction mechanism between Au and semiconductor have been studied.1.By the combination of non-epitaxial growth method and ion exchange method in aqueous phase,Au@ Zn S core-shell nanocrystals with tightly contacted interface can be fabricated,in which the size of the Au core can be flexibly controlled.The UV-Vis absorption spectra demonstrated their favorable visible light absorption capacity.Furthermore,we compared the photocatalytic hydrogen evolution activity of the Au@ Zn S core-shell nanocrystals with different core size and explored their internal photocatalytic mechanism.2.We have developed a hydrothermal cation exchange strategy to fabricate Au@Zn S-Ag Au S/Au Y-S NCs with three kinds of hetro-interfaces,including metal-semiconductor interface,semiconductor-semiconductor interface and cocatalyst-semiconductor interface.By adjusting the thermodynamic and kinetic of the cation exchange reaction process,Au@Zn S-Ag Au S Y-S nanostructures with tunable interior voids and compositions have been fabricated well here.This unprecedented evolution can be reasonably explained by cation exchange initialized chemical etching of Au core,followed by the diffusion through the shell to be Ag Au S and then Zn S through the TEM,XRD and XPS analysis.The UV-Vis absorption spectra evolution and visible light photocatalytic performances,includ ing improved photodegradation behavior and photocatalytic hydrogen evolution activity,have demonstrated their enhanced photocatalytic performance and applications.3.Here,we reported a controllable aqueous-phase synthesis of Au@Cd S core-shell colloidal NCs with tunable shell thickness,high-quality interface and quasi-single-crystalline shell on metal Au core via non-epitaxial growth.The Mid-IR femotosecond pump-probe transient absorption spectroscopy measurement of the products indicated the efficient SPR-induced hot electron injection from metal to semiconductor under visible light irradiation.