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.