First demonstration of rainbow photocatalysts using ternary Cd 1-xZnxSe nanorods of varying compositions

An T. Nguyen, Wei Hao Lin, Yi Hsuan Lu, Yao De Chiou, Yung-Jung Hsu*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

17 Scopus citations

Abstract

We demonstrated for the first time that the assembly of Cd 1-xZnxSe nanorods (NRs) with five compositions (x = 0, 0.35, 0.54, 0.61, 1) may absorb the whole visible spectrum in a gradient fashion for photoconversion applications. The samples were prepared by conducting cation exchange reactions on Ag2Se NRs with excess Cd2+ and Zn2+ ions. By modulating the molar ratio of Cd2+ to Zn2+ employed, the composition of the resulting Cd 1-xZnxSe NRs can be delicately controlled. Because of the tunability of band edge with stoichiometry, Cd1-xZnxSe NRs of varying compositions absorbed light at different wavelength regions, which spanned almost the entire visible spectrum. As compared to the individual constituent NRs, the NRs assembly exhibited greatly improved photoactivity in photoelectrochemical water splitting as well as superior photocatalytic performance toward methylene blue degradation under white light illumination. This superiority emanates from the composition-gradient configuration that significantly improves the light harvesting efficiency by absorbing almost the whole visible spectrum of the incident white light. The full visible photon harvesting of the NRs assembly was validated by the photocurrent action spectrum which showed spectral accordance with the absorption spectrum. The recycling test manifests that the NRs assembly displayed substantially high stability during its use as photocatalyst. Furthermore, the result of performance evaluation under natural sunlight reveals that the present NRs assembly can be used as practical rainbow photocatalysts which may effectively harvest energy from sunlight. The demonstration from this work may facilitate the use of sophisticated assembly of semiconductor nanocrystals in relevant photoconversion processes where the effectiveness of photon harvesting is determinant.

Original languageEnglish
Pages (from-to)140-147
Number of pages8
JournalApplied Catalysis A: General
Volume476
DOIs
StatePublished - 22 Apr 2014

Keywords

  • Cation exchange
  • Rainbow photocatalysts
  • Solar fuel production

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