Abstract
This study presents a novel visible light-active TiO2 nanotube anode film by sensitization with Bi2O3 nanoparticles. The uniform incorporation of Bi2O3 contributes to largely enhancing the solar light absorption and photoelectric conversion efficiency of TiO2 nanotubes. Due to the energy level difference between Bi2O3 and TiO2, the built-in electric field is suggested to be formed in the Bi2O3 sensitized TiO2 hybrid, which effectively separates the photo-generated electron-hole pairs and hence improves the photocatalytic activity. It is also found that the photoelectric conversion efficiency of Bi2O3 sensitized TiO2 nanotubes is not in direct proportion with the content of the sensitizer, Bi2O3, which should be carefully controlled to realize excellent photoelectrical properties. With a narrower energy band gap relative to TiO2, the sensitizer Bi2O3 can efficiently harvest the solar energy to generate electrons and holes, while TiO2 collects and transports the charge carriers. The new-type visible light-sensitive photocatalyst presented in this paper will shed light on sensitizing many other wide-band-gap semiconductors for improving solar photocatalysis, and on understanding the visible light-driven photocatalysis through narrow-band-gap semiconductor coupling.
Highlights
Study of effective photocatalysts lies in following conditions: (i) the prepared photocatalysts are capable of harvesting the solar energy of full wavelength as much as possible; (ii) high photocatalysis efficiency [1,2]
TiO2-based photocatalysts are only able to capture the ultraviolet (UV) part of the solar light; the UV light energy is comprised of only 4% of the total solar energy reaching earth, along with a rather low photocatalysis efficiency being lower than 1%, in contrast to 43% when visible light region is concerned [11,12]
This paper reports the sensitization of TiO2 nanotubes by coupling a visible light-active semiconductor Bi2O3, affording a good a visible light-absorptivity; this indicates the enhancement of the solar light absorption
Summary
Study of effective photocatalysts lies in following conditions: (i) the prepared photocatalysts are capable of harvesting the solar energy of full wavelength as much as possible; (ii) high photocatalysis efficiency [1,2]. Similar to the function obtained in DSSC, the semiconductor with a narrow band gap can efficiently harvest the solar energy, while wide-band-gap TiO2 is able to separate the photo-generated charge carriers. Different energy band gaps between the sensitizer and TiO2 lead to the generation of a built-in electric field [20], causing the photo-excited charge carriers to inject from one semiconductor to the other [21]. This inhibits the recombination of the generated charge carriers, in the meantime, the photo-generated electrons and holes can be well separated, improving the photocatalytic activity [22]. The structure and photoelectrical properties of the composite are well unraveled
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
