One-step and controllable synthesis of active N-rich graphene nanoclusters-CNT composite via an ultrafast deflagration reaction for oxygen reduction electrocatalysis

One-step and controllable synthesis of carbon-based metal-free ORR catalysts with special nitrogen (N) species via a facile method is especially attractive but still challenging. In this study, pristine carbon nanotube (CNT) is easily modified to form the graphene nanoclusters-CNT (GN-CNT) composite with rich active N species via a facile and one-step energetic material (NaN3) deflagration method for the first time. Thanks to the controllable introduction of defects/edges into the CNT structure during the ultrafast (< 1 s) deflagration reaction, the active N species (graphitic N and pyridinic N) can be doped more susceptibly and account for as high as 85% of the total N content (> 5 at%) in the product, which leads to an excellent ORR performance of the prepared catalyst. An optimized GN-CNT sample is capable of achieving an excellent ORR performance with the half-wave potential of 0.84 V (300 mV positive than Pt/C) and limiting current density of - 5.5 mA.cm(-2) (similar to 10% higher than Pt/C). In addition, the prepared catalysts also show significant higher intrinsic catalytic activity, long-term stability and methanol tolerance than commercial Pt/C. Such an energetic material induced deflagration method may provide a rapid, one-step and controllable way to effectively modify or synthesize other N-doped functional materials which can be widely used in the field of catalysis.

Automated summary

The study successfully synthesized graphene nanoclusters-CNT (GN-CNT) composite with rich active N species via a one-step energetic material deflagration method, showing excellent ORR performance with higher half-wave potential and limiting current density compared to commercial Pt/C catalysts. The method may offer a rapid, one-step, and controllable way to effectively modify or synthesize other N-doped functional materials for catalytic applications.