High-Performance Aerogel DeNOx Catalyst: Catalytic Behavior and Kinetic Modeling

Abstract

The kinetics and the parametric sensitivity of the selective catalytic reduction of NO by NH3 were investigated for a high surface area vanadia−titania aerogel. The catalyst showed high activity at low temperatures and the selectivity to N2 was higher than 99% for all experimental conditions investigated. The addition of up to 2% H2O to the dry feed notably reduced the rate of NO conversion. The effect leveled off for higher H2O concentrations. In the absence of O2 in the feed the activity collapsed, independently whether water was present or not. Small amounts of oxygen resulted in a sharp increase of the reaction rate, but for oxygen concentrations exceeding 4%, the increase diminished. A high tolerance with respect to sulfur dioxide was observed. The estimated activation energy amounted to 60 ± 1 kJ/mol. The microkinetic analysis resulted in a model based on an Eley−Rideal mechanism which describes the kinetic behavior over a wide experimental range.