Au/Ag2MoO4 nanocomposite: A dual-function catalyst for dye degradation and colorimetric detection

The authors have successfully synthesized a distinctive potato-shaped Au/Ag2MoO4 nanocomposite with exceptional photocatalytic capabilities in the degradation of methylene blue (MB) under UV irradiation even in neutral conditions. Furthermore, this material displays noteworthy peroxidase-like oxidation activity, facilitating the detection of hydrogen peroxide (H2O2) and ascorbic acid (AA) in aqueous environments. This detection method relies on the oxidation of 3,3',5,5'-tetramethylbenzidine (TMB). The signal generated by TMB adsorption on the catalyst's surface plays a pivotal role in the oxidation of TMB in the presence of H2O2, resulting in the formation of a distinct blue-colored product. This reaction is equally influenced by the presence of AA, which, owing to its antioxidant properties, impedes the development of the color signal. This colorimetric approach exhibits high sensitivity, boasting low limits of detection (LOD) and quantification (LOQ) of 0.0252 and 0.0839 mM for H2O2, and 1.7724 and 5.7109 mg/L for AA, respectively. The method offers a broad linear range spanning from 0.029 to 26.47 mM for H2O2 and 0 to 40 mg/L for AA with a straightforward, cost-effective analytical procedure, and yields highly reliable results. The proposed method displays superior selectivity in detecting AA and high anti-interference capabilities. These findings underscore the photocatalytic and peroxidation-like activities of Au/Ag2MoO4 nanocomposite, positioning it as a promising candidate for various biomedical applications.