Anchoring H3PW12O40 on 3-aminopropyltriethoxysilane modified graphene oxide: enhanced adsorption capacity and photocatalytic activity toward methyl orange

Abstract

H₃PW₁₂O₄₀ (PW₁₂) was hybridized with 3-aminopropyltriethoxysilane modified graphene oxide (GO–NH₂) sheets using a facile impregnation method, for the removal of organic pollutants in water. The obtained hybrid (PW₁₂/GO–NH₂) was characterized by elemental analysis, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), UV-vis diffuse reflectance spectroscopy (DRS), photoluminescence spectroscopy (PL), transmission electron microscopy (TEM), and photo-electrochemical measurements. Its removal efficiency for organic pollutants was evaluated by the removal of methyl orange (MO). The results show that about 61.8% of MO is adsorbed onto the PW₁₂/GO–NH₂ hybrid upon 2 h of mixing, and after 2 h of irradiation under a high-pressure mercury lamp, MO is further decreased to 17.7%. The adsorption capacity of PW₁₂/GO–NH₂ hybrids is enhanced as compared with GO–NH₂, probably due to enhanced electrostatic attraction and hydrogen-bonding interactions between the hybrid and MO. And the hybrid exhibits a better photocatalytic activity than the homogenous photocatalyst PW₁₂ (1.36 times), which is probably attributed to the effective separation of photo-generated electron–hole pairs. Furthermore, the trapping experiment of active species during the photocatalytic degradation was carried out over PW₁₂/GO–NH₂, revealing that the oxidation of MO by O₂˙⁻ and ˙OH plays a major role in the photocatalytic degradation process.