Heteroarchitectured Ag–Bi2O3–ZnO as a bifunctional nanomaterial

Abstract

Heteroarchitectured Ag–Bi₂O₃–ZnO was synthesized through a simple, cost effective, template free photodeposition-hydrothermal method. This composite material represents a prospective new class of novel catalysts wherein the improved light absorption behavior of a metal doped coupled oxide, Ag–Bi₂O₃–ZnO is anticipated to enhance with the observed benefits of a coupled system of Bi₂O₃–ZnO. Characterization of Ag–Bi₂O₃–ZnO revealed interesting optical and morphological characteristics. XRD patterns indicated that well-crystallized α-Bi₂O₃ was formed on the hexagonal wurtzite phase of ZnO along with Ag in the process. The HR-SEM images revealed the formation of organized intercrossed sheets and peanut shell like structure, which were composed of nanosheets and nanoparticles respectively. Elemental color mapping confirms the homogeneity of Zn, O, Ag and Bi in the catalyst. Ag–Bi₂O₃–ZnO has enhanced absorption in the UV and visible region when compared to Bi₂O₃ and ZnO. This catalyst exhibited enhanced photocatalytic activity for the degradation of Acid Red 1 (AR 1), Evens Blue (EB) and Acid Violet 7 (AV 7) under natural sunlight far exceeding those of the Bi₂O₃, Ag–ZnO, Ag–Bi₂O₃ and ZnO systems at neutral pH. Ag–Bi₂O₃–ZnO was found to be stable and reusable without appreciable loss of photocatalytic activity for up to five runs. Ag–Bi₂O₃–ZnO shows enhanced electrochemical methanol oxidation when compared to Ag–Bi₂O₃, Bi₂O₃–ZnO, Ag–ZnO and ZnO. Enhancement in methanol oxidation current demonstrates its high potential as an anode catalyst in direct methanol fuel cells.