Synthesis, characterization and properties of sulfate-modified silver carbonate with enhanced visible light photocatalytic performance.

Sulfate-modified Ag 2 CO 3 was successfully synthesized via a simple precipitation method. Its visible light photocatalytic performance against the removal of Orange G was found to be significantly enhanced in comparison with the one of pure Ag 2 CO 3 . While SO 4 2- -Ag 2 CO 3 ensured a removal efficiency of 100% of OG within 30 min, the unmodified Ag 2 CO 3 exhibited a degradation threshold at hardly 60%. Likewise, the degradation rate constant in the presence of SO 4 2- -Ag 2 CO 3 photocatalyst was assessed to be twice that determined upon the involvement of pristine Ag 2 CO 3 . Furthermore, Total Organic Carbon (TOC) measurements evidenced the occurrence of a quasi-total mineralization of the dye pollutant upon the use of SO 4 2- -Ag 2 CO 3 photocatalyst. Scavenger experiments highlighted the dominant role of photo-induced h + along with ˙O 3 - ozonide radicals in the OG photocatalytic oxidation mechanism. Reuse cycles revealed that the modification by SO 4 2- is a promising route to improve the stability of silver carbonate against photocorrosion. All these improvements could be ascribed to electronic transfer from the upper SO 4 2- HOMO to the lower Ag 2 CO 3 conduction band.