Ruan, Q;
Miao, T;
Wang, H;
Tang, J;
(2020)
Insight on Shallow Trap States-Introduced Photocathodic Performance in n-Type Polymer Photocatalysts.
Journal of the American Chemical Society
, 142
(6)
pp. 2795-2802.
10.1021/jacs.9b10476.
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Abstract
Graphitic carbon nitride (g-C3N4) is a robust organic semiconductor photocatalyst with proven H2 evolution ability. However, its application in a photoelectrochemical system as a photocathode for H2 production is extremely challenging with the majority of reports representing it as a photoanode. Despite research into constructing g-C3N4 photocathodes in recent years, factors affecting an n-type semiconductor’s properties as a photocathode are still not well-understood. The current work demonstrates an effective strategy to transform an n-type g-C3N4 photoanode material into an efficient photocathode through introducing electron trap states associated with both N-defects and C–OH terminal groups. As compared to the g-C3N4 photoelectrode, this strategy develops 2 orders of magnitude higher conductivity and 3 orders of magnitude longer-lived shallow-trapped charges. Furthermore, the average OCVD lifetime observed for def-g-C3N4 is 5 times longer than that observed for g-C3N4. Thus, clear photocathode behavior has been observed with negative photocurrent densities of around −10 μA/cm2 at 0 V vs RHE. Open circuit photovoltage decay (OCVD), Mott–Schottky (MS) plot, and transient absorption spectroscopy (TAS) provide consistent evidence that long-lived shallow-trapped electrons that exist at about the microsecond time scale after photoexcitation are key to the photocathode behavior observed for defect-rich g-C3N4, thus further demonstrating g-C3N4 can be both a photoanode and a photocathode candidate.
Type: | Article |
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Title: | Insight on Shallow Trap States-Introduced Photocathodic Performance in n-Type Polymer Photocatalysts |
Location: | United States |
Open access status: | An open access version is available from UCL Discovery |
DOI: | 10.1021/jacs.9b10476 |
Publisher version: | https://doi.org/10.1021/jacs.9b10476 |
Language: | English |
Additional information: | This is an open access article published under a Creative Commons Attribution (CC-BY) (https://creativecommons.org/licenses/by/4.0/) License, which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited. |
Keywords: | Photonics, Photovoltage, Defects, Electrical conductivity, X-ray photo, electron spectroscopy |
UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Engineering Science > Dept of Chemical Engineering |
URI: | https://discovery.ucl.ac.uk/id/eprint/10092775 |




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