Comment:
K content was 2.1 atoms nm-2. K was introduced by adding KHCO3 solution to a suspension of the support in water, followed by evaporation under vacuum (T = 323 K, drying (T = 368 K) and calcination (T = 773 K , time = 4 h) in a stream of air. The substrate was anatase and was calcined for 4 h at 973 K.