Elevated temperature scanning tunneling microscopy study of formic acid adsorption and reaction on oxygen (2×1) covered Cu(110)

Abstract

The adsorption and reaction of formic acid on a fully oxygen (2×1) covered Cu(110) surface maintained at 353 K has been studied by scanning tunneling microscopy (STM). Formic acid adsorption is followed in a sequence of images that show the removal of oxygen (2×1) rows preferentially in the 〈001〉 direction. The added copper atoms which were associated with the oxygen reconstruction are liberated and diffuse to create significant areas of the high oxygen coverage O-c(6×2) structure. The adsorbed formate produces a (4×1) structure. Analysis of the STM images allows limits to be placed upon the surface structure of the final formate (4×1) surface revealing a lower local formate density than produced for room temperature adsorption. These two observations lead to an understanding of the significant drop in formic acid uptake which has been reported for a narrow temperature window between 350–420 K on this surface.