Two-dimensional covalent organic frameworks (2D-COFs) are an emerging family of catalytical materials with well-defined molecular structures. The stacking of 2D nanosheets and large intrinsic bandgaps significantly impair their performance. Here, we report coaxial one-dimensional van der Waals heterostructures (1D vdWHs) comprised of a carbon nanotube (CNT) core and a thickness tunable thienothiophene-pyrene COF shell using a solution based in situ wrapping method. Density functional theory calculations and in-operando and ex-situ spectroscopic analysis show that the carbon-sulfur region in the thienothiophene groups is the active catalytic site. The unique coaxial structure enables controllable n-doping from the CNT core to the COF shell depending on COF shell thickness, which lowers the bandgap and work function of COF. Consequently, the charge transfer barrier between the active catalytic site and adsorbed oxygen intermediates becomes lower, resulting in a dramatic enhancement in their catalytic activity for oxygen redox reactions. It enables a high-performance rechargeable zinc-air battery with a specific capacity of 696 mAh gZn-1 under a high current density of 40 mA cm-2 and excellent cycling stability. 1D vdWHs open the door to create multi-dimensional vdWHs for exploring fundamental physics and chemistry, as well as practical applications in electrochemistry, electronics, photonics, and beyond.
@article{arxiv.2009.14396,
title = {One-dimensional van der Waals heterostructures as efficient metal-free oxygen electrocatalysts},
author = {Chang Liu and Fei Liu and Hao Li and Junsheng Chen and Jingyuan Fei and Zixun Yu and Ziwen Yuan and Chaojun Wang and Huiling Zheng and Zongwen Liu and Meiying Xu and Graeme Henkelman and Li Wei and Yuan Chen},
journal= {arXiv preprint arXiv:2009.14396},
year = {2020}
}