Curvature-Dependent Electrochemical Hydrogen Peroxide Synthesis Performance of Oxidized Carbon Nanotubes
Fangxin She, Zhongyuan Guo, Fangzhou Liu, Zixun Yu, Jiaxiang Chen, Yameng Fan, Yaojie Lei, Yuan Chen, Hao Li, Wei Li
Abstract
Surface oxidized carbon nanotubes (o-CNTs) can produce sustainable hydrogen peroxide (H 2 O 2 ) by the two-electron transferred oxygen reduction reaction (2e-ORR). The C atoms neighboring to surface epoxy (C–O–C) groups are recognized as active sites. Herein, we report the CNT curvature, or diameter, dependent ORR activity of o-CNT catalysts. Computation modeling suggests that the curvature can alter epoxy group geometry, exerting greater strain on the C–O bond in smaller diameter o-CNTs that leads to improved activity. This theoretical prediction is further experimentally validated by five o-CNTs of different diameters but comparable oxygenous groups. The o-CNT with the smallest diameter (8 nm) delivers the highest H 2 O 2 Faradaic efficiency (>85%, or molar selectivity >90%) and a mass activity of 161 A g –1 at 0.65 V. This curvature effect provides a strategy to design and synthesize efficient electrocatalysts for peroxide production and beyond.