Metal-Organic Framework-Derived N-Doped Carbon with Controllable Mesopore Sizes for Low-Pt Fuel Cells

Mesoporous structure of carbon materials plays an important role in electrocatalyst design. Constructing carbon supports with tunable mesopores has long been a challenge. Herein, the elaborate regulation of mesopores in N-doped carbon materials is reported by pyrolyzing energetic metal-triazolate (MET) frameworks with different particle sizes and at different ramp rates. Higher thermal transfer rates brought about by smaller particle size and higher ramp rate lead to more violent decomposition with a large number of gases producing, which in turn result in larger mesopores in the derivatives. Consequently, a series of N-doped carbon materials with controllable mesopores are obtained. As a proof-of-concept, ultrafine Pt nanoparticles are enveloped inside these mesopores to acquire high-performance electrocatalysts for oxygen reduction reaction. The optimized catalyst achieves high mass activity of 1.52 A mg(Pt)(-1) at 0.9 ViR-free and peak power density of 0.8 W cm(-2) (H-2-Air) with an ultralow Pt loading of 0.05 mg(Pt) cm(-2) at cathode in fuel cells, highlighting the great advantages of MET-derived carbon materials with controllable mesopores in the preparation of advanced electrocatalysts.

Automated summary

This article reports the fine regulation of mesopores in N-doped carbon materials by pyrolyzing metal-triazolate (MET) frameworks with different particle sizes and ramp rates. The higher thermal transfer rates caused by smaller particle size and higher ramp rate result in more violent decomposition and larger mesopores in the derivatives. Consequently, a series of N-doped carbon materials with controllable mesopores are obtained. As a proof-of-concept, high-performance electrocatalysts for oxygen reduction reaction are achieved by encapsulating ultrafine Pt nanoparticles inside these mesopores.