TY - JOUR
T1 - Impact of Pt(hkl) Electrode Surface Structure on the Electrical Double Layer Capacitance
AU - Xue, Song
AU - Chaudhary, Payal
AU - Nouri, Mohammad Reza
AU - Gubanova, Elena
AU - Garlyyev, Batyr
AU - Alexandrov, Vitaly
AU - Bandarenka, Aliaksandr S.
N1 - Publisher Copyright:
© 2024 American Chemical Society.
PY - 2024/2/14
Y1 - 2024/2/14
N2 - The classical theory of the electrical double layer (EDL) does not consider the effects of the electrode surface structure on the EDL properties. Moreover, the best agreement between the traditional EDL theory and experiments has been achieved so far only for a very limited number of ideal systems, such as liquid metal mercury electrodes, for which it is challenging to operate with specific surface structures. In the case of solid electrodes, the predictive power of classical theory is often not acceptable for electrochemical energy applications, e.g., in supercapacitors, due to the effects of surface structure, electrode composition, and complex electrolyte contributions. In this work, we combine ab initio molecular dynamics (AIMD) simulations and electrochemical experiments to elucidate the relationship between the structure of Pt(hkl) surfaces and the double-layer capacitance as a key property of the EDL. Flat, stepped, and kinked Pt single crystal facets in contact with acidic HClO4 media are selected as our model systems. We demonstrate that introducing specific defects, such as steps, can substantially reduce the EDL capacitances close to the potential of zero charge (PZC). Our AIMD simulations reveal that different Pt facets are characterized by different net orientations of the water dipole moment at the interface. That allows us to rationalize the experimentally measured (inverse) volcano-shaped capacitance as a function of the surface step density.
AB - The classical theory of the electrical double layer (EDL) does not consider the effects of the electrode surface structure on the EDL properties. Moreover, the best agreement between the traditional EDL theory and experiments has been achieved so far only for a very limited number of ideal systems, such as liquid metal mercury electrodes, for which it is challenging to operate with specific surface structures. In the case of solid electrodes, the predictive power of classical theory is often not acceptable for electrochemical energy applications, e.g., in supercapacitors, due to the effects of surface structure, electrode composition, and complex electrolyte contributions. In this work, we combine ab initio molecular dynamics (AIMD) simulations and electrochemical experiments to elucidate the relationship between the structure of Pt(hkl) surfaces and the double-layer capacitance as a key property of the EDL. Flat, stepped, and kinked Pt single crystal facets in contact with acidic HClO4 media are selected as our model systems. We demonstrate that introducing specific defects, such as steps, can substantially reduce the EDL capacitances close to the potential of zero charge (PZC). Our AIMD simulations reveal that different Pt facets are characterized by different net orientations of the water dipole moment at the interface. That allows us to rationalize the experimentally measured (inverse) volcano-shaped capacitance as a function of the surface step density.
UR - http://www.scopus.com/inward/record.url?scp=85184607792&partnerID=8YFLogxK
U2 - 10.1021/jacs.3c11403
DO - 10.1021/jacs.3c11403
M3 - Article
C2 - 38316015
AN - SCOPUS:85184607792
SN - 0002-7863
VL - 146
SP - 3883
EP - 3889
JO - Journal of the American Chemical Society
JF - Journal of the American Chemical Society
IS - 6
ER -