Acidity of a single hydroxyl group measured with atomic precision for first time
Functionalised AFM tip used to assess the acidity of individual OH groups on an indium oxide surface
The acidity of single hydroxyl groups on a metal oxide surface has been determined for the first time using non-contact atomic force microscopy (AFM) and a hydroxyl-functionalised tip.1 With the new setup, researchers in Austria, Germany and the Czech Republic were able to directly assess the proton affinity of individual sites by probing the strength of their hydrogen bonds with the tip. ‘The indium oxide surface we investigated has four different oxygen atoms with different reactivity, which means we can study the proton affinity of four oxygen atoms in one experiment,’ says Margareta Wagner at TU Wien. She believes that this kind of experiment could one day be used to tailor the chemical reactivity of solids atom-by-atom.