TY - JOUR
T1 - Mechanism of Cathodic Performance Enhancement by a Few-Nanometer-Thick Oxide Overcoat on Porous Pt Cathodes of Solid Oxide Fuel Cells
AU - Karimaghaloo, Alireza
AU - Andrade, Angela Macedo
AU - Grewal, Simranjit
AU - Shim, Joon Hyung
AU - Lee, Min Hwan
N1 - Funding Information:
This work was funded by the NASA MUREP Institutional Research Opportunity (MIRO) Program (Grant No. NNX15AQ01A). S.G. and M.H.L. also acknowledge NASA Advanced STEM Training and Research (ASTAR) Fellowship (Grant No. NNX15AW57H).
Publisher Copyright:
© 2017 American Chemical Society.
PY - 2017/3/31
Y1 - 2017/3/31
N2 - In a recent report, we demonstrated that few-nanometer-thick yttria-stabilized zirconia (YSZ) coating on a porous Pt cathode of a solid oxide fuel cell is an excellent facilitator of oxygen reduction reaction (ORR) kinetics and an effective suppressor of Pt agglomeration. In this article, we reveal the actual role of the YSZ overcoat in the ORR process through a series of electrochemical analyses. Without the overcoat, the nanoporous Pt is significantly agglomerated during a high-temperature operation and the ORR becomes limited by the availability of triple phase boundaries (TPBs). An ultrathin YSZ overcoat prevents the ORR process from being limited by TPB area by preserving the morphology of its underlying Pt layer. More importantly, the overcoat acts as an excellent facilitator of the atomic-oxygen-species-mediated chemical process(es) that used to be rate-limiting in the ORR of a noncoated Pt/YSZ system.
AB - In a recent report, we demonstrated that few-nanometer-thick yttria-stabilized zirconia (YSZ) coating on a porous Pt cathode of a solid oxide fuel cell is an excellent facilitator of oxygen reduction reaction (ORR) kinetics and an effective suppressor of Pt agglomeration. In this article, we reveal the actual role of the YSZ overcoat in the ORR process through a series of electrochemical analyses. Without the overcoat, the nanoporous Pt is significantly agglomerated during a high-temperature operation and the ORR becomes limited by the availability of triple phase boundaries (TPBs). An ultrathin YSZ overcoat prevents the ORR process from being limited by TPB area by preserving the morphology of its underlying Pt layer. More importantly, the overcoat acts as an excellent facilitator of the atomic-oxygen-species-mediated chemical process(es) that used to be rate-limiting in the ORR of a noncoated Pt/YSZ system.
UR - http://www.scopus.com/inward/record.url?scp=85020865273&partnerID=8YFLogxK
U2 - 10.1021/acsomega.6b00433
DO - 10.1021/acsomega.6b00433
M3 - Article
AN - SCOPUS:85020865273
SN - 2470-1343
VL - 2
SP - 806
EP - 813
JO - ACS Omega
JF - ACS Omega
IS - 3
ER -