Core-shell Au@AuAg nano-peanuts for the catalytic reduction of 4-nitrophenol: critical role of hollow interior and broken shell structure

Abstract

Bimetallic hollow core-shell nanoparticles have gained immense attention especially, as a high-performance catalyst due to their large surface area and increased number of uncoordinated atoms. But, the synthesis of anisotropic hollow structure with a large number of uncoordinated atoms and tailored hole size remains elusive. Herein we report on the synthesis of peanut-like core-shell nanostructures consisting of Au nanorod as core covered by AuAg alloy shell. The AuAg shell was formed on the Au nanorod core via co-deposition of Ag and Au atoms without disturbing the Au nanorod core. Then we controllably and selectively remove Ag atoms from the shell to create �Broken Shell Peanuts� with a variable hole size between 8�4 nm and 26�7 nm. Further, we utilize these nanostructures with different hole sizes as catalysts to reduce 4-nitrophenol to 4-aminophenol where the broken shell peanut nanostructures with hole size 26�7 nm were found to be 12-times more efficient than the solid shell peanut structures.