Highly efficient nano-octahedral Au/γ-Fe2O3 catalyst synthesized by dealloying combined with calcination for low-temperature CO oxidation

Abstract

Environmental pollution, especially air pollution, has become a critical issue requiring prompt resolution. Herein, we have synthesized a novel catalyst composed of nano-octahedral γ-Fe₂O₃in situ loaded with Au nanoparticles through dealloying Al–Fe–Au alloy ribbons combined with calcination. The formation mechanism of this unique morphology was analyzed, and the catalyst's performance was evaluated through CO oxidation reactions. The test results indicate that the Au/γ-Fe₂O₃ catalyst can completely catalyze CO at 50 °C, and exhibits excellent stability and resistance to H₂O and CO₂ toxicity even under harsh testing conditions. Systematic characterization results reveal that the exceptional performance of the catalyst can be attributed to several key factors. These include the large specific surface area, well-defined nanoporous structure, efficient transfer of free electrons at the interface facilitated by the strong interactions between Au and the γ-Fe₂O₃ support, as well as the high concentration of oxygen vacancies and surface-active oxygen species present. Additionally, the potential conversion pathways of CO over the Au/γ-Fe₂O₃ catalyst were elucidated, revealing that they follow the Langmuir–Hinshelwood and Mars–van Krevelen mechanisms under aerobic and anaerobic conditions, respectively. This study is expected to provide novel insights into the green synthesis of highly active and stable nanoporous catalysts.