Ultrasonic impregnation assisted in-situ photoreduction deposition synthesis of Ag/TiO2/rGO ternary composites with synergistic enhanced photocatalytic activity

Abstract

Abstract New approaches and practices to improve photocatalytic efficiency of materials for remediation of organic and inorganic pollutant has become a top priority. We have developed a graphene-oxide based ternary composite Ag/TiO2/rGO as a green catalyst, and the photocatalytic oxidation and reduction efficiency of the catalyst was thoroughly evaluated for Cr(VI) and tetracycline (TC) remediation in water as potential contaminants. The results suggested that the electronic coupleing system exhibits excellent photocatalytic activity, mainly due to affecting light absorption and higher e−/h+ separation efficiency. The photocatalytic activity of the silver-deposited graphene-supported silver and titanium dioxide was 4.3 and 2.5 times for Cr (VI) and TC remediation, respectively. Furthermore, the service life of the photocatalyst was also evaluated within five recycling studies, indicating that the efficiency of the obtained photocatalyst was maintained above 80%. Electron paramagnetic resonance spectroscopy and the addition of free radical scavengers confirmed that e− act as reducing agents and may be the key (O2·−) to the degradation process. The photocatalytic mechanism was proposed based on the studies obtained. Green catalysts based on graphene-based ternary composites developed in this work can provide effective and economic remediation at higher scale and offer practical application of photo catalysis technology.