Spontaneous linker-free binding of polyoxometalates on nitrogen-doped carbon nanotubes for efficient water oxidation. Issue 5 (16th January 2017)

• Record Type: Journal Article
• Authors: Lee, Gil Yong; Kim, Insu; Lim, Joonwon; Yang, Moon Young; Choi, Dong Sung; Gu, Yujin; Oh, Youngtak; Kang, Seok Hun; Nam, Yoon Sung; Kim, Sang Ouk
• Is Part Of: Journal of materials chemistry. Volume 5:Issue 5(2017)
• Page Start: 1941
• Page End: 1947
• Publication Date: 2017-01-16
• Subjects: Materials -- Research -- Periodicals; Chemistry, Analytic -- Periodicals; Environmental sciences -- Research -- Periodicals; 543.0284
• DOI: 10.1039/c6ta09306j
• Languages: English
• ISSNs: 2050-7488

Abstract

Abstract : Linker-free spontaneous binding of Co4 POMs on NCNTs are presented via electrostatic hybridization for efficient water oxidation at neutral pH. Co4 POM/NCNT hybrids exhibited outstanding catalytic activities for water oxidation under neutral conditions. Abstract : Efficient water oxidation remains a principal challenge for clean fuels via water splitting. Polyoxometalates (POMs) are promising water oxidation catalysts in a neutral medium but their application is commonly limited by low electrical conductivity and poor adhesiveness arising from bulky and electrically insulating ligands. Here we report linker-free spontaneous binding of tetracobalt-based polyoxometalates (Co4 POMs) on nitrogen-doped carbon nanotubes (NCNTs) via electrostatic hybridization. Protonated nitrogen-dopant sites at NCNTs enable linker-free immobilization of the Co4 POMs and fluent electron transfer in the resultant Co4 POM/NCNT hybrid structures, as demonstrated by the low overpotential of 370 mV for the water oxidation at pH 7. Accordingly, the hybrids exhibit fast reaction kinetics with a turnover frequency of 0.211 s −1 at 2.01 V vs. RHE. Density functional theory calculation proposes that POMs vertically align at the NCNT surface exposing the maximal catalytic surfaces. This work suggests a reliable route to highly efficient water oxidation catalysis by employing POMs under neutral conditions and NCNTs as self-binding nanoelectrodes in a synergistic well-oriented hybrid structure.