Alkali tungsten bronzes as soot oxidation catalysts: The key role of electrodonor properties of catalytic surface

The effect of bulk alkali (Li, Na, K, Cs) promotion on the tungsten(VI) oxide catalytic activity in soot oxidation was investigated. Catalyst oxidation and reduction susceptibility investigations have shown, that soot oxidation on the investigated catalysts operates through Mars van Krevelen mechanism. It has been also revealed, that increase in electrodonor properties (lowering the work function) of the A(X)WO(3) (A= Li, Na, K, Cs) catalysts results in enhancing the catalytic activity in soot oxidation with the promotional effect increasing in order: Cs < Na << K approximate to Li.