Facile synthesis of Ag-coated Au-Ag nanoworms and their shell specific etching for enhanced catalytic activity

One-dimensional noble-metal nanoparticles (NPs) and their surface modifications to enhance defect states are critical for heterogeneous catalysis. Herein, we report a remarkable enhancement in the catalytic activity of AuAg nanoworms (NWs) with Ag coating and its subsequent etching using galvanic replacement reaction (GRR). The Au-Ag NWs were fabricated through an uncomplicated single-step recipe and were subsequently coated with Ag using the seed-mediated approach to form core-shell NWs. The surface roughness of core-shell NWs was further increased by exploiting GRR. The catalytic activity of the nanostructures was studied by the catalytic reduction of the 4-nitrophenol to 4-aminophenol model reaction. The catalytic activity of core-shell and rough NWs is found to be 0.273 min-1 and 0.843 min-1, respectively, which is - 22 and - 67 times higher, respectively, compared to Au-Ag NWs. This makes these nanostructures excellent for catalytic applications.