Cesium‑vanadium catalyst with excellent low-temperature catalytic activity for the oxidation of sulfur dioxide to sulfuric acid

Vanadium-based catalysts are widely employed in the oxidation of sulfur dioxide to sulfuric acid. However, in the conventional mixed-milling process, the materials are typically subjected to one-step mixing, and the preparation of vanadium aqueous solution requires acid-base synergistic neutralization, resulting in a cumbersome preparation process and uneven distribution of active components. Furthermore, the catalytic activity is also severely constrained at low temperatures, leading to high SO 2 concentrations in emissions. Herein, a cesium‑vanadium-based catalyst demonstrating exceptional activity even at low temperatures has been created, in which the vanadium aqueous solution is formulated using pure water as the sole solvent without the involvement of any acids or alkalis, and this process is synergistically enhanced by the ultrasonic cavitation effect. The ultrasound cavitation treatment yields a more uniform distribution of components, endowing the catalyst with a more attractive and consistent appearance, along with a notable increase in average rigidity to roughly 116 N/cm. Owing to the specific introduction of cesium, coupled with the enhancement of active sites facilitated by diatomite pretreatment, the catalyst exhibits significant catalytic activity even under low-temperature conditions. Specifically, the conversion efficiency of sulfur dioxide attains 64 % at 410 °C.