Sodium Cation Substitution in Sr2KTa5O15 toward Enhancement of Photocatalytic Conversion of CO2 Using H2O as an Electron Donor

The K and Sr cations (K + and Sr 2+ ) in a Sr 2 KTa 5 O 15 photocatalyst were found to be easily substituted by Na cations (Na + ) to form Sr x K y Na z Ta 5 O 15 by a facile one-pot flux method using a mixture of potassium chloride (KCl) and sodium chloride (NaCl). Sr x K y Na z Ta 5 O 15 fabricated using a mixture of KCl and NaCl with a Ag cocatalyst showed enhanced photocatalytic activity without apparent change in selectivity toward CO for the photocatalytic conversion of CO 2 using H 2 O. The present study demonstrates that the flux treatment significantly affected the phase, morphology, band gap, and surface Sr composition of the catalyst owing to the substitution of K + and Sr 2+ for Na + . The stability and durability of the catalyst were also enhanced as compared to those of the photocatalyst fabricated using only KCl flux due to more stable Ag on the surface of Sr x K y Na z Ta 5 O 15 .