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Plasma-assisted doping of nitrogen into cobalt sulfide for loading cadmium sulfide: A direct Z-scheme heterojunction for efficiently photocatalytic Cr(VI) reduction under visible light.
- Source :
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Chemical Engineering Journal . Aug2021, Vol. 417, pN.PAG-N.PAG. 1p. - Publication Year :
- 2021
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Abstract
- [Display omitted] • Doping nitrogen into CoS x polyhedron via N 2 plasma treatment to yield N-CoS x. • CdS was controllably loaded on N-CoS x forming CdS/N-CoS x photocatalyst. • Surface wettability, conductivity and Fermi level of CoS x were tuned by plasma treatment. • Visible-light photocatalysis for Cr(VI) reduction was achieved with efficiency up to 100%. • A photocatalytic mechanism of direct Z-scheme heterojunction was proposed. A direct Z-scheme heterojunction has been constructed by loading cadmium sulfide (CdS) on cobalt sulfide doped with nitrogen (N-CoS x) by N 2 plasma treatment for efficient photocatalytic Cr(VI) reduction under visible light. It was discovered that the resulting CdS/N-CoS x nanocomposites could present different photocatalytic performances controllably depending on the plasma treatment time and CdS-to-N-CoS x ratios. Especially, the one with 5-min plasma treatment and 8/1 M ratio could exhibit the highest Cr(VI) photoreduction efficiency, which is over four and two folds higher than those of pristine N-CoS x and CdS, respectively. Herein, the plasma-assisted N doping could not only increase the surface wettability and conductivity of CoS x but also decrease its Fermi level for improving the photocatalytic Cr(VI) reduction. More importantly, a direct Z-scheme heterojunction could be constructed by the combination of CdS and N-CoS x with suitable band structures, which could further booster the charge separation and transferring, without sacrificing the redox capacity of photogenerated carriers. The enhanced photocatalytic activity and stability of CdS/N-CoS x nanocomposites could thereby be expected for Cr(VI) reduction, with the efficiency up to 100% within 25 min. Such a direct Z-scheme heterojunction created by the plasma treatment route may promise for the large-scale applications for the removal of various toxic pollutants in the environmental remediation field. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 13858947
- Volume :
- 417
- Database :
- Academic Search Index
- Journal :
- Chemical Engineering Journal
- Publication Type :
- Academic Journal
- Accession number :
- 150290520
- Full Text :
- https://doi.org/10.1016/j.cej.2021.129222