Structural characterization of vanadium pentoxide catalyst for sulphur dioxide oxidation

Abstract

The nature of structural canges during preparation of vanadium pentoxide catalyst have been studied by XRD and ESR technique. XRD studies indicate that VO₂ i.e.V⁴⁺ state is formed as a major phase if the thermal decomposition of NH₄VO₃ is carried out at 200ᵒC. The amount of V⁴⁺ state diminishes gradually at higher temperature. If the thermal decomposition is carried out at 500°C the residual product consists of mainlyV₂O₅ phase. ESR studies confirm the above fact. Incorporation of K₂SO₄ is helpful to stabilize the V⁴⁺ state. The presence of siliceous material (kieselgur) in the system does not influence the oxidation state of vanadium but helps tomaintain a desired pore structure in the finished catalyst.