Effective fabrication of porous Au-Ag alloy nanorods for in situ Raman monitoring catalytic oxidation and reduction reactions

Abstract

Porous metal nanostructures exhibit excellent catalytic properties due to their high surface-to-volume ratios and abundant catalytic active sites. However, it is still challenging to control nanopores density and structural features in a facile route and the preparation of porous alloy nanorods for catalytic application has not been well explored. In this work, we demonstrate a synthetic strategy to fabricate highly porous Au–Ag alloy nanorods (P-AuAgNRs) by critically dealloying Ag atoms from homogeneous solid Au–Ag alloy nanorods (AuAgNRs). Combining the merits of the tunable plasmonic properties of noble metal nanorods, excellent stabilities of alloys, and superior catalytic activities of porous structures, we use the P-AuAgNRs as a Raman probe for the in situ monitoring of the catalytic oxidation of 3,3’,5,5’ tetramethylbenzidine (TMB) and reduction of 4-nitrothiophenol (4-NTP). We also compare their composition-dependent catalytic activities. The results show that P-AuAgNRs possess superior chemical stability and higher catalytic activity than those of core-shell structures due to synergistic structural and chemical mechanisms. This strategy provides a predictive design approach for the next-generation alloy catalysts with high-performance.