Individual High-Quality N-Doped Carbon Nanotubes Embedded with Nonprecious Metal Nanoparticles toward Electrochemical Reaction

Developing highly active and stable nonprecious metal catalysts for electrochemical reactions is desirable but remains a great challenge. Herein, we report a novel metal-ion adsorption-pyrolysis strategy for the controllable zeolitic imidazolate framework-8 derived synthesis of individual high-quality N-doped carbon nanotubes embedded with well-dispersed nonprecious metal nanoparticles, which exhibit superior electrocatalytic activity and stability for electrochemical CO2 reduction reaction, oxygen reduction reaction, and oxygen evolution reaction. Experimental analysis and density functional theory calculations indicate that the remarkable electrocatalytic activities are mainly attributed to the interface effects for the efficient electron transfer from metal nanoparticles to the N-doped carbon shell, as well as the large specific areas, unique tube structures, appropriate doping, high graphitization degree, and robust frameworks. The high reaction stability is attributed to the multiwalled graphitic carbon shells efficiently preventing metal nanoparticles from aggregation, corrosion, and oxidation. This novel synthetic strategy presents a facile universality for synthesizing N-doped carbon nanotube structures and will provide a guideline for developing low-cost, highly active, and stable electrocatalytic materials for sustainable energy conversion.