Fig. 5. Photocatalytic conversion of 4-nitrophenol using different composites. (A) TiO₂ with a single cocatalyst (a) Ag and (b) graphene; (B–D) the dosage of GO sheets in each figure was fixed, which was 0.1, 0.5 and 1.0 wt% in (B), (C), and (D) respectively. However, the dosage of Ag was adjusted from 0.1 to 1.0 wt% in the two kinds of ternary composites: (a) TGA and (b) TAG samples.