Heterostructure Ag@WO3–x Composites with High Selectivity for Breaking Azo-bond

The heterostructure Ag@WO3–x(x=0.1 or 1) composites with high selectivity for breaking azo-bond were obtained by in situ reduction of Ag2WO4. The crystal structure and morphology of Ag@WO3–x were characterized by X-ray powder diffraction(XRD), scanning electron microscope(SEM) and transmission electron microscope(TEM). The residue solution of methyl orange(MO) after degradation was tested by gas chromatograph mass spectrometer (GCMS) to analyze the exact components. The results indicate that the products after degradation are N,N-dimethylaniline, N,N-dimethyl-p-phenylenediamine and sulfanilic acid. This is caused by specific breaking of azo-bond in MO. The azo-bond breaking of MO by Ag@WO3–x could occur in dark without any light illumination. Therefore, we proposed a possible mechanism for this azo-bond breaking reaction based on the reaction condition and results.