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A Crucial Role of Rh Substituent Ion in Photoinduced Internal Electron Transfer and Enhanced Photocatalytic Activity of CdS–Ti (5.2– x )/6 Rh x /2 O 2 Nanohybrids
Author(s) -
Lee Jang Mee,
Jin Hyung Bin,
Kim In Young,
Jo Yun Kyung,
Hwang JungWook,
Wang KangKyun,
Kim Min Gyu,
Kim YongRok,
Hwang SeongJu
Publication year - 2015
Publication title -
small
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.785
H-Index - 236
eISSN - 1613-6829
pISSN - 1613-6810
DOI - 10.1002/smll.201501806
Subject(s) - materials science , photocatalysis , nanosheet , photochemistry , electron transfer , titanate , photoinduced electron transfer , substituent , nanotechnology , catalysis , chemistry , ceramic , stereochemistry , organic chemistry , composite material
The photocatalytic activity and photostability of CdS quantum dot (QD) can be remarkably enhanced by hybridization with Rh‐substituted layered titanate nanosheet even at very low Rh substitution rate (<1%). Mesoporous CdS–Ti (5.2− x )/6 Rh x /2 O 2 nanohybrids are synthesized by a self‐assembly of exfoliated Ti (5.2− x )/6 Rh x /2 O 2 nanosheets with CdS QDs. The partial substitution of Rh 3+ /Rh 4+ ions for Ti 4+ ions in layered titanate is quite effective in enhancing an electronic coupling between hybridized CdS and titanate components via the formation of interband Rh 4d states. A crucial role of Rh substituent ion in the internal electron transfer is obviously evidenced from in situ X‐ray absorption spectroscopy showing the elongation of (RhO) bond under visible light irradiation. This is the first spectroscopic evidence for the important role of substituent ion in the photoinduced electron transfer of hybrid‐type photocatalyst. The CdS–Ti (5.2− x )/6 Rh x /2 O 2 nanohybrids show much higher photocatalytic activity for H 2 production and better photostability than do CdS and unsubstituted CdS–TiO 2 nanohybrid. This result is ascribable to the enhancement of visible light absorptivity, the depression of electron–hole recombination, and the enhanced hole curing of CdS upon Rh substitution. The present study underscores that the hybridization with composition‐controlled inorganic nanosheet provides a novel efficient methodology to optimize the photo‐related functionalities of semiconductor nanocrystal.