Titanium-vanadium denoxing catalyst

To illustrate the strength of a multi-technique analytical approach and the kind of strategy which can be chosen, we will briefly describe the characterization of a titanium/vanadium denoxing catalyst. This work was carried out in our laboratory and was used as a case study by the SAS group (3). 

DENOX (Shell DENOX) A low-temperature, add-on SCR system that operates at between 120 and 350°C. The honeycomb catalyst contains vanadium and titanium. 

In a related set of catalysts a loading of 1% vanadium(v) oxide on titanium dioxide is used. These eatalysts are applied in selective catalytic reduction (SCR) reactions, i.e. the removal of NOx through selective reaction with ammonia from streams eontaining large volumes of o g gen. These eatalysts require the redox aetivity as diseussed above, but also an acidic functionality (to activate the seleetive reduetant (ammonia)). It transpires that the produet of reduetion of the surface V=0 groups (V-OH) is sufficiently acidie for this purpose. This means these V=0 species oriented into the reaction medium beeause of their interaction with Ti02 can act as both redox and acidic surface sites. The mechanism of the deNOx reaction has been extensively studied over these materials. ... 

---