Influence of Surface Adsorption on the Oxygen Evolution Reaction on IrO2(110).
A catalyst functions by stabilizing reaction intermediates, usually through surface adsorption. In the oxygen evolution reaction (OER), surface oxygen adsorption plays an indispensable role in the electrocatalysis. The relationship between the adsorption energetics and OER kinetics, however, has not yet been experimentally measured. Herein we report an experimental relationship between the adsorption of surface oxygen and the kinetics of the OER on IrO2(110) epitaxially grown on a TiO2(110) single crystal. The high quality of the IrO2film grown using molecular-beam epitaxy affords the ability to extract the surface oxygen adsorption and its impact on the OER. By examining a series of electrolytes, we find that the adsorption energy changes linearly with pH, which we attribute to the electrified interfacial water. We support this hypothesis by showing that an electrolyte salt modification can lead to an adsorption energy shift. The dependence of the adsorption energy on pH has implications for the OER kinetics, but it is not the only factor; the dependence of the OER electrocatalysis on pH stipulates two OER mechanisms, one operating in acidic solution and another operating in alkaline solution. Our work points to the subtle adsorption-kinetics relationship in the OER and highlights the importance of the interfacial electrified interaction in electrocatalyst design.
Department of Materials Science and Engineering, Cornell University , Ithaca, New York 14853, United States.
Ding-Yuan
DY
Kuo
Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University , Ithaca, New York 14853, United States.|Kavli Institute at Cornell for Nanoscale Science , Ithaca, New York 14853, United States.
Jason K
JK
Kawasaki
Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University , Ithaca, New York 14853, United States.
Jocienne N
JN
Nelson
Institute of Condensed Matter and Nanosciences (ICMN), Université catholique de Louvain , Louvain-la-Neuve 1348, Belgium.
Jan
J
Kloppenburg
Institute of Condensed Matter and Nanosciences (ICMN), Université catholique de Louvain , Louvain-la-Neuve 1348, Belgium.
Geoffroy
0000-0003-1754-2220
G
Hautier
Laboratory of Atomic and Solid State Physics, Department of Physics, Cornell University , Ithaca, New York 14853, United States.|Kavli Institute at Cornell for Nanoscale Science , Ithaca, New York 14853, United States.
Kyle M
KM
Shen
Department of Materials Science and Engineering, Cornell University , Ithaca, New York 14853, United States.|Kavli Institute at Cornell for Nanoscale Science , Ithaca, New York 14853, United States.
Darrell G
DG
Schlom
Department of Materials Science and Engineering, Cornell University , Ithaca, New York 14853, United States.|Kavli Institute at Cornell for Nanoscale Science , Ithaca, New York 14853, United States.
Jin
0000-0002-3427-4363
J
Suntivich