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Title: Understanding the effects of cationic dopants on α-MnO 2 oxygen reduction reaction electrocatalysis

Nickel-doped α-MnO 2 nanowires (Ni–α-MnO 2) were prepared with 3.4% or 4.9% Ni using a hydrothermal method. A comparison of the electrocatalytic data for the oxygen reduction reaction (ORR) in alkaline electrolyte versus that obtained with α-MnO 2 or Cu–α-MnO 2 is provided. In general, Ni-α-MnO 2 (e.g., Ni-4.9%) had higher n values (n = 3.6), faster kinetics (k = 0.015 cm s –1), and lower charge transfer resistance (R CT = 2264 Ω at half-wave) values than MnO 2 (n = 3.0, k = 0.006 cm s –1, R CT = 6104 Ω at half-wave) or Cu–α-MnO 2 (Cu-2.9%, n = 3.5, k = 0.015 cm s –1, R CT = 3412 Ω at half-wave), and the overall activity for Ni–α-MnO 2 trended with increasing Ni content, i.e., Ni-4.9% > Ni-3.4%. As observed for Cu–α-MnO 2, the increase in ORR activity correlates with the amount of Mn 3+ at the surface of the Ni–α-MnO 2 nanowire. Examining the activity for both Ni–α-MnO 2 and Cu–α-MnO 2 materials indicates that the Mn 3+ at the surface of the electrocatalysts dictates the activity trends within the overall series. Single nanowire resistance measurements conducted on 47 nanowire devices (15 of α-MnO 2,more » 16 of Cu–α-MnO 2-2.9%, and 16 of Ni–α-MnO 2-4.9%) demonstrated that Cu-doping leads to a slightly lower resistance value than Ni-doping, although both were considerably improved relative to the undoped α-MnO 2. As a result, the data also suggest that the ORR charge transfer resistance value, as determined by electrochemical impedance spectroscopy, is a better indicator of the cation-doping effect on ORR catalysis than the electrical resistance of the nanowire.« less
Authors:
ORCiD logo [1] ; ORCiD logo [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1] ;  [1]
  1. Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Publication Date:
Report Number(s):
SAND2017-1258J
Journal ID: ISSN 1932-7447; 651017
Grant/Contract Number:
AC04-94AL85000
Type:
Accepted Manuscript
Journal Name:
Journal of Physical Chemistry. C
Additional Journal Information:
Journal Volume: 121; Journal Issue: 5; Journal ID: ISSN 1932-7447
Publisher:
American Chemical Society
Research Org:
Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
Sponsoring Org:
USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE
OSTI Identifier:
1343628

Lambert, Timothy N., Vigil, Julian A., White, Suzanne E., Delker, Collin J., Davis, Danae J., Kelly, Maria, Brumbach, Michael T., Rodriguez, Mark A., and Swartzentruber, Brian S.. Understanding the effects of cationic dopants on α-MnO2 oxygen reduction reaction electrocatalysis. United States: N. p., Web. doi:10.1021/acs.jpcc.6b11252.
Lambert, Timothy N., Vigil, Julian A., White, Suzanne E., Delker, Collin J., Davis, Danae J., Kelly, Maria, Brumbach, Michael T., Rodriguez, Mark A., & Swartzentruber, Brian S.. Understanding the effects of cationic dopants on α-MnO2 oxygen reduction reaction electrocatalysis. United States. doi:10.1021/acs.jpcc.6b11252.
Lambert, Timothy N., Vigil, Julian A., White, Suzanne E., Delker, Collin J., Davis, Danae J., Kelly, Maria, Brumbach, Michael T., Rodriguez, Mark A., and Swartzentruber, Brian S.. 2017. "Understanding the effects of cationic dopants on α-MnO2 oxygen reduction reaction electrocatalysis". United States. doi:10.1021/acs.jpcc.6b11252. https://www.osti.gov/servlets/purl/1343628.
@article{osti_1343628,
title = {Understanding the effects of cationic dopants on α-MnO2 oxygen reduction reaction electrocatalysis},
author = {Lambert, Timothy N. and Vigil, Julian A. and White, Suzanne E. and Delker, Collin J. and Davis, Danae J. and Kelly, Maria and Brumbach, Michael T. and Rodriguez, Mark A. and Swartzentruber, Brian S.},
abstractNote = {Nickel-doped α-MnO2 nanowires (Ni–α-MnO2) were prepared with 3.4% or 4.9% Ni using a hydrothermal method. A comparison of the electrocatalytic data for the oxygen reduction reaction (ORR) in alkaline electrolyte versus that obtained with α-MnO2 or Cu–α-MnO2 is provided. In general, Ni-α-MnO2 (e.g., Ni-4.9%) had higher n values (n = 3.6), faster kinetics (k = 0.015 cm s–1), and lower charge transfer resistance (RCT = 2264 Ω at half-wave) values than MnO2 (n = 3.0, k = 0.006 cm s–1, RCT = 6104 Ω at half-wave) or Cu–α-MnO2 (Cu-2.9%, n = 3.5, k = 0.015 cm s–1, RCT = 3412 Ω at half-wave), and the overall activity for Ni–α-MnO2 trended with increasing Ni content, i.e., Ni-4.9% > Ni-3.4%. As observed for Cu–α-MnO2, the increase in ORR activity correlates with the amount of Mn3+ at the surface of the Ni–α-MnO2 nanowire. Examining the activity for both Ni–α-MnO2 and Cu–α-MnO2 materials indicates that the Mn3+ at the surface of the electrocatalysts dictates the activity trends within the overall series. Single nanowire resistance measurements conducted on 47 nanowire devices (15 of α-MnO2, 16 of Cu–α-MnO2-2.9%, and 16 of Ni–α-MnO2-4.9%) demonstrated that Cu-doping leads to a slightly lower resistance value than Ni-doping, although both were considerably improved relative to the undoped α-MnO2. As a result, the data also suggest that the ORR charge transfer resistance value, as determined by electrochemical impedance spectroscopy, is a better indicator of the cation-doping effect on ORR catalysis than the electrical resistance of the nanowire.},
doi = {10.1021/acs.jpcc.6b11252},
journal = {Journal of Physical Chemistry. C},
number = 5,
volume = 121,
place = {United States},
year = {2017},
month = {1}
}