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Revealing and Facilitating the Rate-Determining Step for Efficient Sunlight-Driven Photocatalysis

Authors :
Jiazang Chen
Houkui Xiang
Zhijian Wang
Source :
The Journal of Physical Chemistry Letters. 12:7665-7670
Publication Year :
2021
Publisher :
American Chemical Society (ACS), 2021.

Abstract

Because of the complex composition of the apparent activation energy, the rate-determining step in a photocatalytic reaction like hydrogen evolution is still being explored even after sluggish oxygen evolution is replaced with efficient hole extraction. This issue severely limits the implementation of certain strategies like the synergistic thermal effect. Here, by developing a combined monitor method based on open-circuit potential decay, we demonstrate that semiconductor-cocatalyst interfacial electron transfer occurring on a decisecond to second time scale dominates photocatalytic hydrogen evolution. This time scale is approximately 6-12 orders of magnitude larger than the widely reported values of picoseconds to microseconds and is comparable to that predicted by Durrant et al. To improve photocatalytic hydrogen evolution, we manage to create more intermediate sites by electronically doping the semiconductor surface. This measure promotes semiconductor-cocatalyst interfacial electron transfer by charge recombination and makes the synergistic thermal effect very evident.

Details

ISSN :
19487185
Volume :
12
Database :
OpenAIRE
Journal :
The Journal of Physical Chemistry Letters
Accession number :
edsair.doi.dedup.....f2b72ba5ed5217965247b22486248dc1