Exploring tin tantalates and niobates as prospective catalyst supports for water electrolysis

In an attempt to identify new electrochemically stable catalyst supports for electrolysis of water, the electronic structure of Sn2Ta2O7, Sn2Nb2O7, SnTa2O6, and SnNb2O6 compounds doped with small amounts of As, Sb, Bi, Cr, Mo, and W has been calculated using the Vienna ab-initio simulation package (VASP), within the projector augmented-wave (PAW) method in the general gradient approximation (GGA) for conducting the exchange-correlation corrections. The role of incorporating the additional 5A and 6B elements in improving the electronic conductivity is discussed. Based on the calculated values of the cohesive energies for the materials and their type of electronic conductivity, we hypothesize that the thoreaulite structure of SnTa2O6 doped with As, Sb, or Bi are the most appropriate candidates for use as catalyst supports in water electrolysis.