2.1 Materials
All chemicals used in this experiment were of analytical grade and used without further purification.
2.1.1 Preparation of Mn0.05Cd0.95S
The Mn0.05Cd0.95S solid solutions were synthesized according to the previous report [33]. In a typical process, manganese acetate tetrahydrate (0.44 g), cadmium acetate anhydrous (1.919 g) and thioacetamide (2.5 g) were added into 20 mL of ethylenediamine and 40 mL deionized water and dispersed by sonication for 20 min. After stirring for 1.5 h, the mixture solution was transferred into a Teflon-lined autoclave (80 mL), the autoclave was maintained at 160 oC for 24 h. After cooling naturelly, the yellow sediment was centrifuged and washed by deionized water and absolute ethyl alcohol respectively and then dried at 60 oC for 10 h to get the Mn0.05Cd0.95S composite which named as MCS.