Mechanistic Studies of the Oxygen Evolution Reaction by a Cobalt-Phosphate Catalyst at Neutral pH

被引:1073
作者
Surendranath, Yogesh [1 ]
Kanan, Matthew W. [1 ]
Nocera, Daniel G. [1 ]
机构
[1] MIT, Dept Chem, Cambridge, MA 02139 USA
基金
美国国家科学基金会;
关键词
COUPLED ELECTRON-TRANSFER; SURFACE INTERMEDIATE STATES; WATER OXIDATION; EVOLVING CATALYST; ELECTROCHEMICAL EVOLUTION; ALKALINE-SOLUTION; RENEWABLE ENERGY; OXIDE ELECTRODES; SPRAY-PYROLYSIS; REACTION ORDER;
D O I
10.1021/ja106102b
中图分类号
O6 [化学];
学科分类号
0703 ;
摘要
The mechanism of the oxygen evolution reaction (OER) by catalysts prepared by electrodepositions from Co2+ solutions in phosphate electrolytes (Co-Pi) was studied at neutral pH by electrokinetic and O-18 isotope experiments. Low-potential electrodepositions enabled the controlled preparation of ultrathin Co-Pi catalyst films (<100 nm) that could be studied kinetically in the absence of mass transport and charge transport limitations to the OER. The Co-Pi catalysts exhibit a Tafel slope approximately equal to 2.3 x RT/F for the production of oxygen from water in neutral solutions. The electrochemical rate law exhibits an inverse first order dependence on proton activity and a zeroth order dependence on phosphate for [Pi] >= 0.03 M. In the absence of phosphate buffer, the Tafel slope is increased similar to 3-fold and the overall activity is greatly diminished. Together, these electrokinetic studies suggest a mechanism involving a rapid, one electron, one proton equilibrium between Co-III-OH and Co-IV-O in which a phosphate species is the proton acceptor, followed by a chemical turnover-limiting process involving oxygen-oxygen bond coupling.
引用
收藏
页码:16501 / 16509
页数:9
相关论文
共 65 条
[21]   Proton-coupled electron transfer [J].
Cukier, RI ;
Nocera, DG .
ANNUAL REVIEW OF PHYSICAL CHEMISTRY, 1998, 49 :337-369
[22]   INTERFACIAL PROPERTIES OF OXIDES USED AS ANODES IN THE ELECTROCHEMICAL TECHNOLOGY [J].
DAGHETTI, A ;
LODI, G ;
TRASATTI, S .
MATERIALS CHEMISTRY AND PHYSICS, 1983, 8 (01) :1-90
[23]   ANODIC OXIDE-FILMS AS BARRIERS TO CHARGE-TRANSFER IN O2 EVOLUTION AT PT IN ACID SOLUTIONS [J].
DAMJANOVIC, A ;
JOVANOVIC, B .
JOURNAL OF THE ELECTROCHEMICAL SOCIETY, 1976, 123 (03) :374-381
[24]   Molecular chemistry of consequence to renewable energy [J].
Dempsey, JL ;
Esswein, AJ ;
Manke, DR ;
Rosenthal, J ;
Soper, JD ;
Nocera, DG .
INORGANIC CHEMISTRY, 2005, 44 (20) :6879-6892
[25]   Nickel-borate oxygen-evolving catalyst that functions under benign conditions [J].
Dinca, Mircea ;
Surendranath, Yogesh ;
Nocera, Daniel G. .
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA, 2010, 107 (23) :10337-10341
[26]   Ground state changes induced by Ni substitution in NaxCoO2 [J].
Gayathri, N. ;
Bharathi, A. ;
Sastry, V. S. ;
Sundar, C. S. ;
Hariharan, Y. .
SOLID STATE COMMUNICATIONS, 2006, 138 (10-11) :489-493
[27]  
Gileadi E., 1993, ELECTRODE KINETICS C, P127
[28]  
Grimes C.A., 2008, Light, Water, Hydrogen: The Solar Generation of Hydrogen by Water Photoelectrolysis
[30]   KINETICS OF THE ELECTROCHEMICAL EVOLUTION OF ISOTOPICALLY ENRICHED GASES .2. 0-180-16 EVOLUTION OF NICO2O4 AND LIXCO3-XO4 IN ALKALINE-SOLUTION [J].
HIBBERT, DB ;
CHURCHILL, CR .
JOURNAL OF THE CHEMICAL SOCIETY-FARADAY TRANSACTIONS I, 1984, 80 :1965-1975