TY - JOUR
T1 - Oxygen evolution in Co-doped RuO2 and IrO2
T2 - Experimental and theoretical insights to diminish electrolysis overpotential
AU - González-Huerta, R. G.
AU - Ramos-Sánchez, G.
AU - Balbuena, P. B.
N1 - Funding Information:
GRS acknowledges CONACYT for support this research with a postdoctoral fellowship. This work was partially supported by IPN multidisciplinary Project SIP-1540/2014 and by Secretaría de Ciencia, Tecnología, e Inovación del DF, SECITI DF , agreement ICYTDF/193/2012 . Computational resources from Texas A&M Supercomputer facility, Texas A&M University Brazos HPC cluster, and Texas Advanced Computer Center (TACC) are greatly acknowledged.
PY - 2014/12/15
Y1 - 2014/12/15
N2 - Development of proton exchange membrane (PEM) water electrolysis systems has been held back by the cost of membrane and precious metal electrocatalyst components, and by the high overvoltage for water splitting. Since non-noble metal electrocatalysts with satisfactory activities are not currently available, costs must be reduced by improving performance and durability of noble metal electrocatalysts. Moreover, it is mandatory to understand the mechanisms of oxygen evolution and find out how the reaction kinetics could be improved. Here the kinetic pathway for oxygen evolution reaction (OER) on RuO2, IrO2 and RuIrCoOx surfaces is analyzed with electrochemical polarization and Density Functional Theory (DFT) analyses of the changes occurring when pure oxides are doped with Co and their effect during the first stages of oxygen evolution. Experimental electrochemical methods are used to find indicators of electrocatalyst quality: the lower the Tafel slope, the faster the reaction kinetics and the more active the electrocatalyst. It is found that RuIrCoOx surfaces show the lowest Tafel slope value, 0.068 V dec-1, and the rate determining step at low overpotential is the second H-O breaking. Changes in electronic structure responsible of the sluggish second reduction step in comparison to the first are identified by the theoretical study.
AB - Development of proton exchange membrane (PEM) water electrolysis systems has been held back by the cost of membrane and precious metal electrocatalyst components, and by the high overvoltage for water splitting. Since non-noble metal electrocatalysts with satisfactory activities are not currently available, costs must be reduced by improving performance and durability of noble metal electrocatalysts. Moreover, it is mandatory to understand the mechanisms of oxygen evolution and find out how the reaction kinetics could be improved. Here the kinetic pathway for oxygen evolution reaction (OER) on RuO2, IrO2 and RuIrCoOx surfaces is analyzed with electrochemical polarization and Density Functional Theory (DFT) analyses of the changes occurring when pure oxides are doped with Co and their effect during the first stages of oxygen evolution. Experimental electrochemical methods are used to find indicators of electrocatalyst quality: the lower the Tafel slope, the faster the reaction kinetics and the more active the electrocatalyst. It is found that RuIrCoOx surfaces show the lowest Tafel slope value, 0.068 V dec-1, and the rate determining step at low overpotential is the second H-O breaking. Changes in electronic structure responsible of the sluggish second reduction step in comparison to the first are identified by the theoretical study.
KW - Density functional theory
KW - Doped oxides
KW - Electrocatalysis
KW - Oxygen evolution reaction
UR - http://www.scopus.com/inward/record.url?scp=84903159821&partnerID=8YFLogxK
U2 - 10.1016/j.jpowsour.2014.06.029
DO - 10.1016/j.jpowsour.2014.06.029
M3 - Artículo
SN - 0378-7753
VL - 268
SP - 69
EP - 76
JO - Journal of Power Sources
JF - Journal of Power Sources
ER -