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Accelerating Electron-Transfer and Tuning Product Selectivity Through Surficial Vacancy Engineering on CZTS/CdS for Photoelectrochemical CO 2 Reduction.
- Source :
-
Small (Weinheim an der Bergstrasse, Germany) [Small] 2021 Aug; Vol. 17 (31), pp. e2100496. Date of Electronic Publication: 2021 Jun 25. - Publication Year :
- 2021
-
Abstract
- Copper-based chalcogenides have been considered as potential photocathode materials for photoelectrochemical (PEC) CO <subscript>2</subscript> reduction due to their excellent photovoltaic performance and favorable conduction band alignment with the CO <subscript>2</subscript> reduction potential. However, they suffer from low PEC efficiency due to the sluggish charge transfer kinetics and poor selectivity, resulting from random CO <subscript>2</subscript> reduction reaction pathways. Herein, a facile heat treatment (HT) of a Cu <subscript>2</subscript> ZnSnS <subscript>4</subscript> (CZTS)/CdS photocathode is demonstrated to enable significant improvement in the photocurrent density (-0.75 mA cm <superscript>-2</superscript> at -0.6 V vs RHE), tripling that of pristine CZTS, as a result of the enhanced charge transfer and promoted band alignment originating from the elemental inter-diffusion at the CZTS/CdS interface. In addition, rationally regulated CO <subscript>2</subscript> reduction selectivity toward CO or alcohols can be obtained by tailoring the surficial sulfur vacancies by HT in different atmospheres (air and nitrogen). Sulfur vacancies replenished by O-doping is shown to favor CO adsorption and the CC coupling pathway, and thereby produce methanol and ethanol, whilst the CdS surface with more S vacancies promotes CO desorption capability with higher selectivity toward CO. The strategy in this work rationalizes the interface charge transfer optimization and surface vacancy engineering simultaneously, providing a new insight into PEC CO <subscript>2</subscript> reduction photocathode design.<br /> (© 2021 Wiley-VCH GmbH.)
Details
- Language :
- English
- ISSN :
- 1613-6829
- Volume :
- 17
- Issue :
- 31
- Database :
- MEDLINE
- Journal :
- Small (Weinheim an der Bergstrasse, Germany)
- Publication Type :
- Academic Journal
- Accession number :
- 34173332
- Full Text :
- https://doi.org/10.1002/smll.202100496