Facile synthesis of dysprosium oxide/bismuth oxide nanocomposite electrode materials with good electrocatalytic performance

Benzoic acid is widely applied in the food field, including beverages as the antimicrobial preservative due to its strong inhabitation role to bacteria and yeasts. However, excessive intake of benzoic acid can easily cause abdominal pain and diarrhea and can even result in metabolic diseases. Hence, it is important to seek simple, accurate and sensitive strategies to detect low-trace benzoic acid. The aim of this study is to synthesize dysprosium oxide/bismuth oxide nanocomposites using dysprosium sulphate and sodium bismuthate as the raw materials and research the electrochemical sensing properties for the detection of benzoic acid. Dysprosium oxide/bismuth oxide nanocomposites were synthesized by a facile hydrothermal route. The dysprosium oxide/bismuth oxide nanocomposites were characterized by X-ray diffraction, electron microscopy, X-ray photoelectron spectroscopy and electrochemical impedance spectroscopy. The dysprosium oxide/bismuth oxide nanocomposites are composed of nearly circular-shaped particles with polycrystalline cubic Dy2O3 and triclinic Bi2O3 phases. The size of the nearly circular-shaped particles is about 50 to 200 nm. The electrons are easier to transfer by the dysprosium oxide/bismuth oxide nanocomposite-modified electrode than the bare electrode. A pair of quasi-reversible cyclic voltammetry (CV) peaks located at -0.155 V and -0.582 V exist in the CV curve of 0.1 M KCl buffer solution containing 2 mM benzoic acid. The nanocomposite-modified electrode shows a linear detection range and detection limit of 0.001-2 mM and 0.18 μM, respectively, for benzoic acid detection. The dysprosium oxide/bismuth oxide nanocomposite-modified electrode reveals superior electro-catalytic activity towards benzoic acid.