A DFT study of formic acid decomposition on the stoichiometric SnO2 surface as a function of iso-valent doping

In the present work, we have studied the effect of iso-valent dopants on the chemical reactivity of the stoichiometric SnO2 (110) surface. Si, Ge, Pb, Ti, Zr, Hf, and Ce ions have been placed at the Sn lattice sites (substitutional doping) in bulk, sub-surface, and surface positions. The results show that surface or sub-surface sites are clearly preferred over the bulk ones. Next, we studied the effect of the iso-valent dopants on the adsorption and decomposition reaction of HCOOH molecule. On this basis, four paths with desorption of: (a) H2, (b) CO, (c) H2O, or (d) CO2 can occur. Comparing the results of this decomposition reaction on the SnO2 surface with the same process on rutile TiO2 (110) having the same structure and morphology, reveals that SnO2 is considerably more reactive in all reaction steps of the formic acid decomposition.