Boron-nitrogen-doped carbon dots on multi-walled carbon nanotubes for efficient electrocatalysis of oxygen reduction reactions

Cost-effective production of metal-free catalysts for the oxygen-reduction reaction (ORR), to supersede Pt-based catalysts, is challenging. Here, a three-dimensional nanocatalyst was prepared by compounding multi-wall carbon nanotubes (MWCNTs) with easily modified and doped carbon dots (CDs) as sources of B and N. The catalyst has high conductivity and a large specific surface area similar to the MWCNTs, allowing exposure of many CDs with rich edge active sites and enhancing electron transfer. The catalyst exhibits excellent ORR performance, with 0.92 V of E-onset vs reversible hydrogen electrode (RHE). The E-1/2 value exhibits a reduction of 50 mV compared with that of Pt/C (0.85 V) with a limited current density of 5.95 mA cm(-2). The enhanced catalytic performance is attributed to the synergy of pyridine N and BC3. This work describes a simple and economical strategy for metal-free catalysts, and promotes the development of such catalysts for metal-air batteries and fuel cells. (C) 2021 Elsevier Inc. All rights reserved.

Automated summary

A three-dimensional nanocatalyst was prepared by compounding multi-wall carbon nanotubes with carbon dots as sources of B and N, exhibiting excellent ORR performance. The catalyst shows high conductivity and a large specific surface area, promoting the development of metal-free catalysts for metal-air batteries and fuel cells.