Preparation and Properties of Cu2O/TiO2 Heterojunction Nanocomposite for Rhodamine B Degradation under Visible Light

Abstract

AbstractCu2O/TiO2 heterojunction nanocomposite particles were prepared through hydrothermal method. X‐ray diffractometer (XRD), static nitrogen adsorption apparatus, DelsaNano C particle analyzer, SEM, TEM, ultraviolet visible light spectrophotometer (UV‐Vis) were employed to characterize and reveal the microcosmic characteristics, surface micromorphology and optical features of the Cu2O/TiO2 heterojunction nanocomposite particles. The photocatalytic degradation regularity of rhodamine B utilizing Cu2O/TiO2 heterojunction nanocomposite was optimized via the response surface methodology (RSM), and the quadratic regression equation of the degradation rate and coding of experimental variables were constructed. First principle calculation was applied through density function theory (DFT), the binding energies of the heterojunction of multiple Cu2O crystal surfaces and TiO2 were computed by Vienna Ab‐Initio Simulation Package. The results showed that the prepared Cu2O/TiO2 heterojunction nanocomposite crystal nanoparticles had high purity with a Cu2O crystallization preferential orientation of (111) plane. TiO2 doped Cu2O nanocomposite increased the forbidden band width, specific surface, dispersibility and absorbance efficiency in the visible light range. R2 value of the constructed quadratic regression equation was 0.9233, showing the constructed regression model was available and the photocatalytic process and the established model had good fitness. The optimum conditions for the rhodamine B degradation were obtained as follows: the photocatalytic time was 3 h, the amount of catalyst was 40 mg/L and the solution pH value was 3. The experimental degradation rate of rhodamine B was predicted to be 91.8% and the relative error between the theoretical value and the experimental value was 2.8%. All the calculated binding energies of Cu2O/TiO2 heterojunction nanocomposites were positive and Cu2O (111)/TiO2 heterojunction nanocomposites were most likely to present high catalytic activity. The photocatalytic degradation mechanism, transfer and separation laws of photogenerated carriers of Cu2O/TiO2 p‐n heterojuncion were explored and revealed.