Irradiation assisted polyacrylamide gel route for the synthesize of the Mg1–x Co x Al2O4 nano-photocatalysts and its optical and photocatalytic performances

The present work demonstrated the synthesis of the CoxMg1–xAl2O4 (x = 0.1, 0.2, 0.3, 0.4, and 0.5) photocatalysts with an p–n xMgAl2O4/(1 – x)[CoAl2O4] junction, as novel simulated sunlight-driven photocatalysts at different Co/Mg molar ratios. A gamma-ray irradiation assisted polyacrylamide gel route was used to synthesize the CoxMg1–xAl2O4 pigments. The micro-structure, phase purity, surface morphology, the cation distribution, and the electron level, color, optical and electrochemical properties, and photocatalytic activity of the CoxMg1–xAl2O4 photocatalysts were systematically analyzed. The mean particle size of the CoxMg1–xAl2O4 photocatalysts increases with increase in the x value was demonstrated by TEM. Color and optical properties analysis indicated that the CoxMg1–xAl2O4 photocatalysts exhibits a bright blue color. As the x value increased to 0.2, the b* value of the CoxMg1–xAl2O4 photocatalysts reached to –21.468, it means that the CoxMg1–xAl2O4 possessed low Co content and exhibited a stabilized color and optical properties. Photocatalytic degradation experiments revealed that the CoxMg1–xAl2O4 (x = 0.1) photocatalysts exhibit highest photocatalytic activity for the degradation of the methylene blue (MB) dye under simulated sunlight irradiation. The synergistic effects of the adsorption capacity, light absorption capacity, and superoxide ions (•O2−) played important role for the photocatalytic degradation of the MB dye on the basis of the UV–Vis spectra, XPS analysis, electrochemical test, and photocatalytic degradation experiments