title: Monitoring of galvanic replacement reaction between silver nanowires and HAuCl4 by in situ transmission X-ray microscopy.
abstract: Galvanic replacement reaction between silver nanowires and an aqueous solution of HAuCl(4) has been successfully monitored in real time by using in situ transmission X-ray microscopy (TXM) in combination with a flow cell reactor. The in situ observations clearly show the morphological evolution of the solid silver nanowires to hollow gold nanotubes in the course of the reaction. Careful analysis of the images reveals that the galvanic replacement reaction on the silver nanowires involves multiple steps: (i) local initiation of pitting process; (ii) anisotropic etching of the silver nanowires and uniform deposition of the resulting gold atoms on the surfaces of the nanowires; and (iii) reconstruction of the nanotube walls via an Ostwald ripening process. The in situ TXM represents a promising approach for studying dynamic processes involved in the growth and chemical transformation of nanomaterials in solutions, in particular for nanostructures with dimensions larger than 50 nm.
authors: Center for Nanoscale Materials, Argonne National Laboratory , 9700 South Cass Avenue, Argonne, Illinois 60439, United States. ygsun@anl.gov
authors: Yugang
authors: Y
authors: Sun
authors: Yuxin
authors: Y
authors: Wang