TY - JOUR
T1 - Topotactic transformation of bismuth oxybromide into bismuth tungstate
T2 - bandgap modulation of single-crystalline {001}-faceted nanosheets for enhanced photocatalytic CO2 reduction
AU - Kong, Xin Ying
AU - Tong, Tong
AU - Ng, Boon Junn
AU - Low, Jingxiang
AU - Zeng, Tingying Helen
AU - Mohamed, Abdul Rahman
AU - Yu, Jiaguo
AU - Chai, Siang Piao
N1 - Funding Information:
This work was funded by the Ministry of Education (MOE) Malaysia and Universiti Sains Malaysia (USM) under NanoMITe-LRGS (project code 203/PJKIMIA/6720009). The main author, X. Y. Kong , would like to specially thank The Jeffrey Cheah Travel Grant for funding part of the work conducted at Harvard University.
Publisher Copyright:
Copyright © 2020 American Chemical Society.
Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2020/6/17
Y1 - 2020/6/17
N2 - The photocatalytic conversion of CO2 to energy-rich CH4 solar fuel is an ideal strategy for future energy generation as it can resolve global warming and the imminent energy crisis concurrently. However, the efficiency of this technology is unavoidably hampered by the ineffective generation and utilization of photoinduced charge carriers. In this contribution, we report a facile in situ topotactic transformation approach where {001}-faceted BiOBr nanosheets (BOB-NS) were employed as the starting material for the formation of single-crystalline ultrathin Bi2WO6 nanosheets (BWO-NS). The as-obtained BWO-NS not only preserved the advantageous properties of the 2D nanostructure and predominantly exposed {001} facets but also possessed enlarged specific surface areas as a result of sample thickness reduction. As opposed to the commonly observed bandgap broadening when the particle sizes decrease to an ultrathin nanoscale owing to the quantum size effect, the developed BWO-NS exhibited a fascinating bandgap narrowing compared to those of pristine Bi2WO6 nanoplates (BWO-P) synthesized from a conventional one-step hydrothermal approach. Moreover, the electronic band positions of BWO-NS were modulated as a result of ion exchange for the reconstruction of the energy bands, where BWO-NS demonstrated significant upshifting of CB and VB levels; these are beneficial for photocatalytic reduction applications. This propitious design of BWO-NS through integrating the merits of BOB-NS caused BWO-NS to exhibit substantial 2.6 and 9.3-fold enhancements of CH4 production over BOB-NS and BWO-P, respectively.
AB - The photocatalytic conversion of CO2 to energy-rich CH4 solar fuel is an ideal strategy for future energy generation as it can resolve global warming and the imminent energy crisis concurrently. However, the efficiency of this technology is unavoidably hampered by the ineffective generation and utilization of photoinduced charge carriers. In this contribution, we report a facile in situ topotactic transformation approach where {001}-faceted BiOBr nanosheets (BOB-NS) were employed as the starting material for the formation of single-crystalline ultrathin Bi2WO6 nanosheets (BWO-NS). The as-obtained BWO-NS not only preserved the advantageous properties of the 2D nanostructure and predominantly exposed {001} facets but also possessed enlarged specific surface areas as a result of sample thickness reduction. As opposed to the commonly observed bandgap broadening when the particle sizes decrease to an ultrathin nanoscale owing to the quantum size effect, the developed BWO-NS exhibited a fascinating bandgap narrowing compared to those of pristine Bi2WO6 nanoplates (BWO-P) synthesized from a conventional one-step hydrothermal approach. Moreover, the electronic band positions of BWO-NS were modulated as a result of ion exchange for the reconstruction of the energy bands, where BWO-NS demonstrated significant upshifting of CB and VB levels; these are beneficial for photocatalytic reduction applications. This propitious design of BWO-NS through integrating the merits of BOB-NS caused BWO-NS to exhibit substantial 2.6 and 9.3-fold enhancements of CH4 production over BOB-NS and BWO-P, respectively.
KW - bandgap modulation
KW - bismuth-based layered structures
KW - photocatalytic COreduction
KW - topotactic transformation
KW - {001} facets
UR - http://www.scopus.com/inward/record.url?scp=85086682808&partnerID=8YFLogxK
U2 - 10.1021/acsami.9b15950
DO - 10.1021/acsami.9b15950
M3 - Article
C2 - 32433865
AN - SCOPUS:85086682808
VL - 12
SP - 26991
EP - 27000
JO - ACS Applied Materials & Interfaces
JF - ACS Applied Materials & Interfaces
SN - 1944-8244
IS - 24
ER -