The preparation and photocatalytic activity of phosphotungstic acid-reduced graphene oxide composites

In this work, phosphotungstic acid-reduced graphene oxide composites (denoted as HPW-RGO) were synthesized using phosphotungstic acid and self-made graphene oxide as starting materials via a facile hydrothermal method. The prepared materials were characterized by scanning electron microscopy, X-ray diffraction analysis, infrared spectroscopy, X-ray photoelectron spectroscopy and thermograv- imetric analysis. The results showed that the phosphotungstic acid particles were loaded on reduced graphene oxide. The optimal mass ratio of graphite oxide to HPW was 3.0 wt% in preparation process. Under the same experimental condition (pH 3.0, 20 mg/L methyl orange (MO) and 1.0 g/L dosage), the adsorption removal ratio of MO over HPW-3RGO was 46.34%, the photocatalytic degradation removal ratio is about 40.00%, and the total removal ratio was 86.34%. While the adsorption removal ratio of MO over HPW was only 2.67%, the photocatalytic degradation removal ratio is about 32.00% and the total removal ratio was only 34.66%. The degradation rate constant of HPW-3RGO (0.00892 min-1) was 3.4 times of the HPW (0.00264 min-1).