Water-dispersible, sulfonated hyperbranched poly(ether-ketone) grafted multiwalled carbon nanotubes as oxygen reduction catalysts.

Sohn, Gyung-Joo; Choi, Hyun-Jung; Jeon, In-Yup; Chang, Dong Wook; Dai, Liming; Baek, Jong-Beom · ACS Nano · 2012

basic_science · Level V

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Abstract

To endorse sufficient water affinity to multiwalled carbon nanotubes (MWCNTs), dendritic hyperbranched poly(ether-ketone) (HPEK) was first covalently grafted to the surface of a MWCNT via a Friedel-Crafts acylation reaction. The resultant HPEK-grafted MWCNT (HPEK-g-MWCNT) was subsequently sulfonated in chlorosulfonic acid to produce sulfonated HPEK-g-MWCNT (SHPEK-g-MWCNT), which is dispersible well in water showing a zeta potential value of -57.8 mV. The SHPEK-g-MWCNT paper simply formed by filtration of aqueous dispersion has a sheet resistance as low as 63 Ω/sq. Its thin film shows a high electrocatalytic activity for oxygen reduction reaction (ORR). Thus, the newly produced water-dispersible MWCNT is a new class of high performance cathode material for ORR.