TY - JOUR
T1 - On/Off Boundary of Photocatalytic Activity between Single- And Bilayer MoS2
AU - Taniguchi, Takaaki
AU - Nurdiwijayanto, Leanddas
AU - Li, Shisheng
AU - Lim, Hong En
AU - Miyata, Yasumitsu
AU - Lu, Xueyi
AU - Ma, Renzhi
AU - Tang, Dang Ming
AU - Ueda, Shigenori
AU - Ueda, Shigenori
AU - Tsukagoshi, Kazuhito
AU - Sasaki, Takayoshi
AU - Osada, Minoru
AU - Osada, Minoru
N1 - Funding Information:
Prof. Shintaro Ida (Kumamoto University) and Mr. Keisuke Awaya (Kumamoto University) are thanked for fruitful discussions. This work was in part supported by World Premier International Research Center Initiative (WPI Initiative on Materials Nanoarchitronics), MEXT, the Grant-in-Aid for Scientific Research KAKENHI, JSPS, Creation of Life Innovation Materials for Interdisciplinary and International Researcher Development Satellite, MEXT, and the joint usage/research program of the Institute of Materials and Systems for Sustainability (IMaSS), Nagoya University. The HAXPES measurements were performed under the approval of NIMS Synchrotron X-ray Station (Proposal Nos. 2016A4604, 2016B4604, and 2017A4604). We also acknowledge Mr. Hirohito Ohata (Materials Analysis Station, NIMS) for XPS analysis.
Publisher Copyright:
© 2020 American Chemical Society.
PY - 2020/6/23
Y1 - 2020/6/23
N2 - Molecularly thin two-dimensional (2D) semiconductors are emerging as photocatalysts owing to their layer-number-dependent quantum effects and high charge separation efficiency. However, the correlation among the dimensionality, crystallinity, and photocatalytic activity of such 2D nanomaterials remains unclear. Herein, a Ag photoreduction technique coupled with microscopic analyses is employed to spatially resolve the photocatalytic activity of MoS2 as a model catalyst. Interestingly, we find that only monolayer (1L)-MoS2 is active for a Ag photoreduction reaction. The photocatalytic activity of 1L-MoS2 is enhanced by a built-in electrical field originated from the MoS2/SiO2 interface, instead of by the specific surface structure and quantum electronic state of 1L-MoS2. Furthermore, we observe photocatalytic active sites to be geometrically distributed on triangular 1L-MoS2 crystals, wherein the Ag particles are preferentially deposited on the outermost zigzag edges and defective inner parts of the triangular grains. The degradation of photocatalytic activity and electron mobility with the formation of Mo(VI) species indicates that the species inhibit the in-plane diffusion of the photogenerated electrons to the reductive sites. The monolayer-selectivity, activation, and inactivation mechanisms, unveiled in this work, will offer future directions in designing 2D nanophotocatalysts.
AB - Molecularly thin two-dimensional (2D) semiconductors are emerging as photocatalysts owing to their layer-number-dependent quantum effects and high charge separation efficiency. However, the correlation among the dimensionality, crystallinity, and photocatalytic activity of such 2D nanomaterials remains unclear. Herein, a Ag photoreduction technique coupled with microscopic analyses is employed to spatially resolve the photocatalytic activity of MoS2 as a model catalyst. Interestingly, we find that only monolayer (1L)-MoS2 is active for a Ag photoreduction reaction. The photocatalytic activity of 1L-MoS2 is enhanced by a built-in electrical field originated from the MoS2/SiO2 interface, instead of by the specific surface structure and quantum electronic state of 1L-MoS2. Furthermore, we observe photocatalytic active sites to be geometrically distributed on triangular 1L-MoS2 crystals, wherein the Ag particles are preferentially deposited on the outermost zigzag edges and defective inner parts of the triangular grains. The degradation of photocatalytic activity and electron mobility with the formation of Mo(VI) species indicates that the species inhibit the in-plane diffusion of the photogenerated electrons to the reductive sites. The monolayer-selectivity, activation, and inactivation mechanisms, unveiled in this work, will offer future directions in designing 2D nanophotocatalysts.
KW - MoS
KW - nanosheets
KW - photocatalyst
KW - photodeposition
KW - two-dimensional materials
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U2 - 10.1021/acsnano.9b09253
DO - 10.1021/acsnano.9b09253
M3 - Article
C2 - 32396324
AN - SCOPUS:85087095331
VL - 14
SP - 6663
EP - 6672
JO - ACS Nano
JF - ACS Nano
SN - 1936-0851
IS - 6
ER -