In-situ growth of Fe(III)/tannic acid/polyvinyl pyrrolidone composite on carbon nanotubes for enhanced electroreduction of oxygen

The development of efficient electrocatalyst for oxygen reduction reaction (ORR) is of great scientific interest. Multiwalled carbon nanotubes (MWCNTs), with large surface area, good electrical conductivity and mechanical strength, have been proven an ideal platform for the construction of novel electrocatalyst for ORR. Herein, a high-performance electrocatalyst for ORR was fabricated by in-situ synthesis of Fe(III)/tannic acid (TA)/polyvinyl pyrrolidone (PVP) composite on MWCNT. MWCNT was firstly modified with PVP chains ultrasonically in the PVP solution. Then, TA, a polyphenolic compound, and Fe(III) cations were added into the PVP solution. During the growth of Fe(III)/tannic acid (TA)/polyvinyl pyrrolidone (PVP) on MWCNT, TA grasps PVP chains through either hydrogen or ionic bonds and cross-links them together by forming coordinating bonds with Fe(III) ions. Fe(III)/TA/PVP/MWCNT exhibits excellent catalytic activity for ORR, good methanol tolerance and high durability, suggesting the synergistic effect between Fe(III)/TA/PVP composite and MWCNT.