Template-free and one-pot synthesis of N-doped hollow carbon tube @ hierarchically porous carbon supporting homogeneous AgNPs for robust oxygen reduction catalyst

Abstract Porous C/Ag nanohybrids were one type of emerging and promising alternative oxygen reduction catalysts for Pt, which was crucial to energy conversion and storage devices. Herein, a template-free, sustainable and in-situ method was employed for preparing N-doped hollow carbon tube @ hierarchically porous carbon supporting homogeneous Ag nanoparticles (HCT@HPC@AgNPs) by one-pot carbonization with the assist of “chelating effect”. It was very interesting that the “chelating effect” can inhibit the self-aggregation of AgNPs during its growing process, since Ag + can be well immobilized on precursor. Moreover, during the carbonization process, an amazing N-doped hollow carbon tube @ porous carbon was also achieved by the synergistic effect of thermal degradation, spontaneous bubble-template and self-doping. The resultant HCT@HPC@AgNPs was investigated by physical characterizations and electrochemical tests. The results indicated that HCT@HPC@AgNPs delivered distinct electrocatalytic activity towards oxygen reduction reaction (ORR), long-term durability and anti-toxic capacity in alkaline electrolyte, which was comparable or even better than Pt/C. Thus, HCT@HPC@AgNPs was a promising ORR catalyst for application in the field of energy and catalysis.