Gold nanotube membranes have catalytic properties

This work presents the fabrication of gold nanotube membranes (GNT) using gold deposition on porous anodic aluminum oxide (AAO) template and demonstrates the catalytic properties generated by the nanostructured gold surface. AAO membranes were prepared by electrochemical anodization of Al in 0.3 M oxalic acid electrolyte. Electroless gold deposition on AAO was performed via several steps using commercially available gold plating solutions. Scanning electron microscopy (SEM) images confirm that the gold nanotubes formed inside AAO pores have characteristic nanoclustered morphology as a result of the nucleation process during gold deposition. It was found that catalytic properties of GNT membranes depend on the size of gold nanoclusters which can be controlled by pH during nucleation process. The excellent catalytic properties (catalytic rate constant k = 0.132 min−1) of the GNT membranes were demonstrated by testing catalytic conversion of 4-nitrophenol (4-NP) into 4-aminophenol (4-AP) in the presence of NaBH4 as a reductant. The correlation between the size of gold nanoclusters and catalytic activity was verified showing the capability of controlling and further improving catalytic properties of GNT membranes.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Gold nanotube membranes were prepared by electroless gold deposition using porous alumina as a template. ► Nanoclustered morphology of prepared gold nanotubes was observed. ► Catalytic conversion of 4-nitrophenol into 4-aminophenol was investigated. ► Catalytic properties of gold nanotube membranes were confirmed for the first time. ► The first order kinetic and high catalytic rate constant (k = 0.132 min−1) is determined.