Z-scheme reduced graphene oxide/TiO2-Bronze/W18O49 ternary heterostructure towards efficient full solar-spectrum photocatalysis

Abstract

Z-scheme reduced graphene oxide (rGO)/TiO2-bronze (TiO2-B)/W18O49 photocatalyst consisted of rGO, super-thin TiO2-B nanosheets, and W18O49 nanofibers was fabricated by a two-step solvothermal synthesis route. The TiO2-B nanosheets were tightly attached on rGO firstly. W18O49 nanowires were then grown on rGO/TiO2-B. Precursors and reaction conditions play important roles for getting the optimal microstructure. The ternary photocatalyst is able to absorb sunlight ranging from ultraviolet to near infrared regions, which makes full use of light for efficiently photocatalytic degrading organic pollutants. The light absorption intensity and photon-generated carrier transfer efficiency are both improved with adding rGO. The localized surface plasmon resonance effect arose from the nonstoichiometric W18O49 is in favour of the absorption range of the rGO/TiO2-B/W18O49 composite broadening to near infrared light range. The photocatalytic mechanism of Z-scheme rGO/TiO2-B/W18O49 composite was verified by an electron spin resonance test. The conduction band of TiO2-B and the valence band of W18O49 are used in the photocatalytic degradation of rhodamine B, facilitating the efficient separation of photogenerated carriers. The rGO/TiO2-B/W18O49 heterostructure exhibits an excellent photocatalytic performance under full solar-spectrum irradiation. The result may represent a new strategy for the construction of nanocomposites with suitable band structure in the efficient application of full solar light.