TY - JOUR
T1 - Energetic basis of catalytic activity of layered nanophase calcium manganese oxides for water oxidation
AU - Birkner, Nancy
AU - Nayeri, Sara
AU - Pashaei, Babak
AU - Najafpour, Mohammad Mahdi
AU - Casey, William H.
AU - Navrotsky, Alexandra
PY - 2013/5/28
Y1 - 2013/5/28
N2 - Previous measurements show that calcium manganese oxide nanoparticles are better water oxidation catalysts than binary manganese oxides (Mn3O4, Mn2O3, and MnO2). The probable reasons for such enhancement involve a combination of factors: The calcium manganese oxide materials have a layered structure with considerable thermodynamic stability and a high surface area, their low surface energy suggests relatively loose binding of H2O on the internal and external surfaces, and they possess mixed-valent manganese with internal oxidation enthalpy independent of the Mn3+/ Mn4+ ratio and much smaller in magnitude than the Mn2O3-MnO2 couple. These factors enhance catalytic ability by providing easy access for solutes and water to active sites and facile electron transfer between manganese in different oxidation states.
AB - Previous measurements show that calcium manganese oxide nanoparticles are better water oxidation catalysts than binary manganese oxides (Mn3O4, Mn2O3, and MnO2). The probable reasons for such enhancement involve a combination of factors: The calcium manganese oxide materials have a layered structure with considerable thermodynamic stability and a high surface area, their low surface energy suggests relatively loose binding of H2O on the internal and external surfaces, and they possess mixed-valent manganese with internal oxidation enthalpy independent of the Mn3+/ Mn4+ ratio and much smaller in magnitude than the Mn2O3-MnO2 couple. These factors enhance catalytic ability by providing easy access for solutes and water to active sites and facile electron transfer between manganese in different oxidation states.
KW - Nanomaterials
KW - Thermochemistry
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U2 - 10.1073/pnas.1306623110
DO - 10.1073/pnas.1306623110
M3 - Article
C2 - 23667149
AN - SCOPUS:84878448492
SN - 0027-8424
VL - 110
SP - 8801
EP - 8806
JO - Proceedings of the National Academy of Sciences of the United States of America
JF - Proceedings of the National Academy of Sciences of the United States of America
IS - 22
ER -