Abstract
Anatase TiO2 hollow nanoboxes were synthesized and combined with the graphene oxide to get nanocomposite of TiO2/rGO (TG). Graphene oxide was used to modify the Oxygen-Clusters and bulk to surface defects. Anatase and TG composite were characterized with the positron annihilation, XPS, EPR, EIS and photocurrent response analysis. The relative affects of defects on the photocatalytic reduction (CO2 to CH4) were studied. The TG composites showed highest photo-catalytic activity after GO coupling (49 µmol g−1 h−1), 28.6 times higher photocurrent yields much higher quantum efficiency (3.17%@400 nm) when compared to the TiO2 nanoboxes. The mechanism of enhanced photo-catalytic CO2 conversion to CH4 elucidated through electrochemical and photo-catalytic experiments with traceable isotope containing carbon dioxide (13CO2). For the first time we discovered that diminishing the comparative concentration ratio of anatase from the bulk to surface defects could significantly increase the conversion of CO2 to CH4.
Highlights
PALS is capable to probe surface and bulk defects, sensitive to all kinds of defects defects with complex structures such as open volume porousity, aggregates, voids, disclocations and grain boundaries
PALS is a good addition to the XPS, electron paramagnetic resonance (EPR) and photoluminescence spectroscopy (PL) techniques
We found that lowering the relative bulk to surface defects concentration ratio improved the photocatalysis efficiency
Summary
The obtained TG sample shows TiO2 peaks because rGO is not sensitive to the XRD (Supplementary Fig. 1a(ii))[8]. The variation of τ2 value from 0.3937 ns to 0.3864 ns was evident that the TiO2 nanoboxes contain an abundance of surface oxygen defects and compressive bonding but reduced to atomic dimensions in the TG composites. The samples were further investigated by the XPS to get information about the chemical composition, oxygen vacancies and Ti oxidation-state inside TiO2 nano-boxes after microwave treatment with the rGO. The O1s spectrum of TiO2 nanobox (Fig. 2a) shows a peak at the binding energy of 529.3 eV, corresponding to the Ti(IV)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
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.
