Issue 14, 2018

Surface stoichiometry manipulation enhances solar hydrogen evolution of CdSe quantum dots

Abstract

Surface stoichiometry is a sensitive parameter affecting the decay dynamics of photogenerated hole–electron pairs of QDs. However, the effect of this manipulation on artificial photocatalytic H2 evolution is unclear. Here, we report that surface stoichiometry manipulation is a facile and feasible approach for enhancing H2 photogeneration of QDs. In the absence of an external cocatalyst, a decrease in the surface Se ratio of CdSe QDs from ∼16.7% to ∼4.9% gives a more than 10-fold increase in solar H2 evolution. Taking Ni(II) as an external cocatalyst, CdSe QDs with a surface Se ratio of ∼4.9% can produce ∼1600 ± 151 μmol H2 gas during 27 h of visible-light irradiation, giving a total turnover number of (1.24 ± 0.12) × 105 on CdSe QDs and an apparent quantum yield of 10.1%, which is about 8 times that of CdSe QDs with a surface Se ratio of ∼16.7% under the same conditions. Mechanistic insights obtained by a combination of steady-state and time-resolved spectroscopic techniques indicate that surface stoichiometry exerts a significant influence on the exciton kinetics of CdSe QDs: a higher ratio of surface Se would increase the possibility of exciton recombination through hole trapping, thus depressing the performance of solar H2 evolution.

Graphical abstract: Surface stoichiometry manipulation enhances solar hydrogen evolution of CdSe quantum dots

Supplementary files

Article information

Article type
Paper
Submitted
12 Jan 2018
Accepted
06 Mar 2018
First published
07 Mar 2018

J. Mater. Chem. A, 2018,6, 6015-6021

Surface stoichiometry manipulation enhances solar hydrogen evolution of CdSe quantum dots

M. Huang, X. Li, Y. Gao, J. Li, H. Wu, L. Zhang, C. Tung and L. Wu, J. Mater. Chem. A, 2018, 6, 6015 DOI: 10.1039/C8TA00385H

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements