American Chemical Society
ja6b10657_si_001.pdf (1.03 MB)

Mechanistic Investigation of Water Oxidation Catalyzed by Uniform, Assembled MnO Nanoparticles

Download (1.03 MB)
journal contribution
posted on 2016-12-28, 00:00 authored by Kyoungsuk Jin, Hongmin Seo, Toru Hayashi, Mani Balamurugan, Donghyuk Jeong, Yoo Kyung Go, Jung Sug Hong, Kang Hee Cho, Hirotaka Kakizaki, Nadège Bonnet-Mercier, Min Gyu Kim, Sun Hee Kim, Ryuhei Nakamura, Ki Tae Nam
The development of active water oxidation catalysts is critical to achieve high efficiency in overall water splitting. Recently, sub-10 nm-sized monodispersed partially oxidized manganese oxide nanoparticles were shown to exhibit not only superior catalytic performance for oxygen evolution, but also unique electrokinetics, as compared to their bulk counterparts. In the present work, the water-oxidizing mechanism of partially oxidized MnO nanoparticles was investigated using integrated in situ spectroscopic and electrokinetic analyses. We successfully demonstrated that, in contrast to previously reported manganese (Mn)-based catalysts, Mn­(III) species are stably generated on the surface of MnO nanoparticles via a proton-coupled electron transfer pathway. Furthermore, we confirmed as to MnO nanoparticles that the one-electron oxidation step from Mn­(II) to Mn­(III) is no longer the rate-determining step for water oxidation and that Mn­(IV)O species are generated as reaction intermediates during catalysis.