EPR, DFT, and Mott-Schottky study on visible light photocatalytic activity of Au and Co3O4 mediated Bi2WO6: role of SPR and multi-valence states

Au nanoparticles modified p-n hetero-structured Co3O4/Bi2WO6 composites was synthesized in present paper, and the photocatalytic activity and photocurrent density were measured to be as high as 97.2% with good stability and high photocurrent density. Relative influential factors and possible mechanism were thoroughly discussed through various techniques. The morphology, specific surface area, structure, and chemical valence states of Au/Co3O4/Bi2WO6 were evaluated using X-ray diffraction, electron transition microscopy, N-2 adsorption-desorption method, and X-ray photoelectron spectra. Metallic Au nanoparticles were decorated on surface of 2.5 mu m-spheres with nano-sheets Co3O4/Bi2WO6 which showed characteristic Raman and Infrared vibration modes. Possible influential factors such as UV-Vis absorption, energy band gap, and active radical's studies revealed that the modification of Au and Co3O4 greatly enhanced the light harvesting capability and e(-)/h(+) separation, resulting in the high degradation efficiency of Au/Co3O4/Bi2WO6. DFT simulations were performed which matched well with experimental results. A reasonable degradation mechanism was proposed based on thoroughly studies on possible influential factors such as electron transition, charge transfer, energy band gap, density of states, and oxygen vacancies. The photocatalytic parameters were sufficient promising after compared with literatures.

Automated summary

In this paper, Au nanoparticles modified p-n hetero-structured Co3O4/Bi2WO6 composites were synthesized, showing high photocatalytic activity and stability. Various techniques were used to evaluate the performance and mechanisms of the composite material.