Graphene supported ceria-titania mixed oxide composite-An effective photo catalyst for methylene blue (MB) dye degradation

Abstract

In the present study we have prepared graphene supported CeO₂-TiO₂ mixed oxide and studied its activity towards photocatalytic degradation of methylene blue (MB) dye. The mixed oxide is prepared with the variation of cerium loading to that of titanium from 2% to 10% by sol-gel method and graphene oxide (GO) is prepared by using modified Hummer’s method. The resulting adsorbent nanocomposite is synthesised by chemical reduction method with GO loading 2% by weight to that of mixed metal oxide and employed in the catalytic process through batch wise adsorption to test the optimum level of activity by varying the parameters (pH: 3-10, time: 15-75 min, dye concentration: 5-40 ppm, anions like Cl^-, SO₄^2-, NO₃^-, HCO₃^-) with catalyst loading 0.020 g per 0.100 L of the dye solution. It is inferred that the adsorbent catalyst nanocomposite with ceria loading up to 5% with that of titania has better catalytic activity towards the photodegradation of MB with the optimum condition of pH-10 and time-75 minutes. Degraded product characterisation is carried out by LC-MS technique, which confirmed the degradation of MB. The adsorption kinetics is being investigated through pseudo-first-order kinetics and Langmuir adsorption model with good fitting having R² value 0.986 and 0.993 respectively.