Study of the Phosphorus Deactivation Effect and Resistance of Vanadium-Based Catalysts

We investigated the effects of phosphorus (P) on the catalytic activity and properties of V/W/Ti and V/Sb/Ce/Ti. As a result of investigating changes in the physicochemical properties of each catalyst added with P, in the V/W/Ti catalyst, P was bound to vanadium or tungsten in the form of PO3- (metaphosphate) and produced phosphate species. During this process, the Bronsted acid site on the catalyst surface was greatly increased, and the adsorption amount of ammonia of the catalyst was increased. However, the active site (V=O) and redox properties were reduced, which inhibited the reactivity of adsorbed ammonia, and as a result, the selective catalytic reduction (SCR) efficiency was decreased. In contrast, V/Sb/Ce/Ti catalysts preferentially produce Ce-phosphate and Sb-phosphate. In this process, the production of PO3- and the reduction of the active site were suppressed, indicating high P resistance. In addition, with a low P content, the redox properties were increased, such that the SCR activity was improved.