The interconversion of SnO2(110) reduced phases by reaction with formic acid

Angle-resolved photoemission (ARPES), Auger electron spectroscopy (AES) and low energy electron diffraction (LEED) are used to study modifications to the surface electronic structure and symmetry of reduced SnO2(110)1 X 1 and 1 X 2 surfaces, following interaction with formic acid. Formic acid adsorbs molecularly on both surfaces at 105 K and is desorbed by annealing to 375 K, leaving no carbon residues on the surface. LEED shows that while the surface order of the 1 X 1 reduced surface remains unchanged by this treatment the half order beams from the 1 X 2 surface are completely removed. ARPES spectra from the 1 X 1 surface are unaffected by formic acid adsorption and annealing, but for the 1 X 2 surface change to resemble the 1 X 1 surface data. We speculate that the interaction either removes or replaces bridging oxygen sites on the 1 X 2 surface.