TY - JOUR
T1 - Origin of the High Selectivity of the Pt-Rh Thin-Film H2Gas Sensor Studied by Operando Ambient-Pressure X-ray Photoelectron Spectroscopy at Working Conditions
AU - Toyoshima, Ryo
AU - Tanaka, Takahisa
AU - Kato, Taro
AU - Uchida, Ken
AU - Kondoh, Hiroshi
N1 - Funding Information:
We thank the staff of the Keio University Center Service Facilities for Research and the Photon Factory for their technical support. This study was supported by the Grants-in-Aid for scientific research (19H00756). The experiments were performed under the approval of the Photon Factory Program Advisory Committee (PF PAC 2018S2-005, 2021S2-003, 2021G613).
Publisher Copyright:
© 2022 American Chemical Society.
PY - 2022/9/15
Y1 - 2022/9/15
N2 - The Pt-Rh thin-film sensors exhibit excellent sensitivity and selectivity for H2 gas detection. Here, we studied the mechanism of highly selective detection of H2 by the Pt-Rh thin-film sensors with ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) measurements at working conditions, which were paralleled with electric resistivity measurements. The elemental composition and chemical state of surface Pt and Rh drastically change depending on the background gas environments, which directly link to the sensor response. It is revealed that surface segregated Pt atoms accelerate dissociative adsorption of H2, resulting in a reduction of the sensor surface and then a decrease of electric resistivity of the film, whereas a thin oxidized Rh layer blocks dissociation of the other reducing agent, that is, NH3. This is supported from the adsorption energetics obtained by the density functional theory (DFT) calculations.
AB - The Pt-Rh thin-film sensors exhibit excellent sensitivity and selectivity for H2 gas detection. Here, we studied the mechanism of highly selective detection of H2 by the Pt-Rh thin-film sensors with ambient-pressure X-ray photoelectron spectroscopy (AP-XPS) measurements at working conditions, which were paralleled with electric resistivity measurements. The elemental composition and chemical state of surface Pt and Rh drastically change depending on the background gas environments, which directly link to the sensor response. It is revealed that surface segregated Pt atoms accelerate dissociative adsorption of H2, resulting in a reduction of the sensor surface and then a decrease of electric resistivity of the film, whereas a thin oxidized Rh layer blocks dissociation of the other reducing agent, that is, NH3. This is supported from the adsorption energetics obtained by the density functional theory (DFT) calculations.
UR - http://www.scopus.com/inward/record.url?scp=85138446850&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85138446850&partnerID=8YFLogxK
U2 - 10.1021/acs.jpclett.2c02365
DO - 10.1021/acs.jpclett.2c02365
M3 - Article
C2 - 36067214
AN - SCOPUS:85138446850
VL - 13
SP - 8546
EP - 8552
JO - Journal of Physical Chemistry Letters
JF - Journal of Physical Chemistry Letters
SN - 1948-7185
IS - 36
ER -