Journal
INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
Volume 46, Issue 10, Pages 7309-7319Publisher
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.ijhydene.2020.11.245
Keywords
Hematite; Oxygen migration; Surface deep traps; Holes transfer; Photoelectrocatalytic water splitting
Categories
Funding
- National Key Research and Development Program of China [2018YFB1502001, 2018YFE0122300]
Ask authors/readers for more resources
Oxygen concentration and distribution in hematite significantly affect holes transfer efficiency, ultimately influencing the performance of photoelectrocatalytic water splitting. Thermal treatment leads to changes in oxygen, impacting holes transfer efficiency.
The holes transfer efficiency is a key issue in the process of photoelectrocatalytic water splitting. Here, we found that the oxygen concentration and distribution in hematite evidently affected the bulk and surface holes transfer, and thus influenced the performance of photoelectrocatalytic water splitting. Two macro-changes on oxygen were observed during the thermal treatment. The first-stage led to a lower bulk O/Fe ratio of only 1/1 and the generation of adsorbed oxygen, obtaining porous nanorods (NRs) with a -1.4 nm FeOx layer. Bulk charge recombination centers and surface deep traps caused a lower bulk and surface charge transfer. The second-stage led to a bulk O/Fe ratio of nearly 3/2 and single high crystallization NRs. Major increases in charge transfer constant from 0.27 to 4.5 s(-1) and in photocurrent density (vs.1.23 VRHE) from 0.0235 to 1.20 mA/cm(2) were observed, which demonstrates the higher holes transfer efficiency. Furthermore, the connection of oxygen migration and charge transfer was derived. This work could provide effective guidance for further optimization of semiconductor photoanodes. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available