Impact of lattice defects on water oxidation properties in SnNb₂O₆ photoanode prepared by pulsed-laser deposition method

SnNb₂O₆ is one of the promising photoanode materials for photoelectrochemical water splitting. We prepared the SnNb₂O₆ thin-film photoanode with various Sn/Nb ratios by a pulsed-laser deposition method and investigated impacts of lattice defects in the SnNb₂O₆ photoanode on the water oxidation property. Photoelectrochemical measurements and Raman spectroscopy analyses for the SnNb₂O₆ photoanodes presented that the water oxidation property can be improved by suppressing the formation of the acceptor site caused by the substitution of Sn⁴⁺ for the Nb⁵⁺ site in the crystal lattice of SnNb₂O₆. This study provides material's design strategy based on defect chemistry to realize an efficient SnNb₂O₆ photoanode used for the photoelectrochemical cell, which can operate without an external bias.