Facile synthesis of cubic Ag/Ag 2 O composites and its shape-dependent photo-catalytic activity examination

Ag/Ag 2 O polyhedrons, cubes and octahedron-like crystals have been fabricated via a simple chemical precipitation at room temperature. Based on experimental results, a reasonable formation mechanism was proposed, the concentration of NaOH may play a crucial role in the growth of Ag/Ag 2 O composites with different morphology. Subsequently, the as-synthesized samples were used in the photo-catalytic degradation of methyl orange to explore its photo-catalytic performance. It was found that the cubic Ag/Ag 2 O exhibited the highest photo-catalytic activity with almost 100% degradation efficiency in 50 min, which may due to the cubic Ag/Ag 2 O has strong visible light absorption properties, tremendous amount of free radicals and high separation rate of electron–hole pairs. Furthermore, the photo-induced free radicals were measured by electron paramagnetic resonance (EPR) measurement. Research demonstrates that the ⋅O 2 − and ⋅OH radicals are the predominant active species. And the feasible mechanism of photo-catalytic degradation is further discussed in detail.