Functionalized MoS2 supported core-shell Ag@Au nanoclusters for managing electronic processes in photocatalysis

Abstract

Metal nanoclusters (MNCs) based on gold as core and silver as shell, abbreviated as Ag@AuNCs, were electrostatically associated with functionalized semiconducting MoS2 nanosheets, abbreviated as f-MoS2. The realization of the Ag@AuNCs/f-MoS2 ensemble was manifested by UV–vis and photoluminescence titration assays, while its morphology was evidenced by high-angle annular dark-field STEM imaging coupled with EDX analyses. Photoinduced intra-ensemble charge-transfer phenomena were witnessed and attributed to the suppression and concomitant shift of Ag@AuNC photoluminescence by incremental additions of f-MoS2. The Ag@AuNCs/f-MoS2 was employed as RhB photodegradation catalyst for wastewater purification from organic pollutant dyes. The production of highly oxidant radicals from the photogenerated electron-hole pairs within Ag@AuNCs/f-MoS2 were found to be the main reactive species, while the holes left on Ag@AuNCs attacked RhB, as evidenced by the disappearance of the characteristic absorption peak. The photocatalytic reaction by the ensemble followed fast kinetics as compared with bare Ag@AuNCs or individual AuNCs and AgNCs.