A novel insight of photodegradation of dye mixture by surface analysis

In this paper, surface analysis methods, including ζ-potential (Zp) and cyclic voltammetry (CV), were utilized to obtain the photodegradation mechanism of dye mixture solutions. Firstly, nanostructured SrTiO3 (STO) was prepared as photocatalyst, which is composed of 35–142 nm particles and with specific surface area of 56.90 m2/g. The highest dye degradation efficiency was obtained in the first 30 min of degradation, and enhanced degradation efficiency of methyl orange (MO) was observed in mixture solutions. CV results exhibit different oxidation potential values that demonstrate degraded accessibility under different pH conditions (original pH, 4.30, 2.40, 1.63). ζ-potential (Zp) is measured at different pH values of unitary and binary solutions. Moreover, the influence factors in faintly acidic, neutral and strong acidic conditions are discussed. Kinetic and correlation between H+ and shift of ζ-potential are also studied.