Surfactant-assisted implantation strategy for facile construction of Pt-based hybrid electrocatalyst to accelerate oxygen reduction reaction

Abstract

A considerable number of strategies have been investigated to construct highly-efficient and stable Pt-based electrocatalysts for promoting the oxygen reduction reaction, which plays a critical role in proton exchange membrane fuel cells and metal-air batteries. In this contribution, Pt-based intermetallic nanoparticles confined in a Co-doped zeolitic imidazolate framework-8 derived carbon matrix with cobalt nanocrystallites and Co-Nx sites decoration are conceptually predicted and experimentally constructed by a novel surfactant-assisted Pt implantation and in-situ alloying strategy. Cationic surfactant cetyltrimethylammonium bromide was simultaneously used as the functional capping ligand to coordinate with [PtCl6]2- and structure-directing agent for synthesis of rod-like Co-doped zeolitic imidazolate framework-8. Systematical characterization and contrast experiments reveal that the Pt-based intermetallic compounds are mainly Pt3Co nanocrystalline, and cetyltrimethylammonium bromide is critically important for Pt reservation and highly dispersion in the resulting electrocatalyst. The as-synthesized Pt3Co/Co@Co–N–C electrocatalyst with a low Pt content (∼7 wt%) shows a positive half-wave potential of 0.922 V and a high limiting current density of ∼6 mA cm−2. More importantly, compared with commercial Pt/C, Pt3Co/Co@Co–N–C features high stability with mass activity increased from 362 mA/mgPt to 400 mA/mgPt after 30,000 voltage cycles from 0.6 to 0.9 V vs. reversible hydrogen electrode. The strategy for the construction of oxygen reduction reaction electrocatalyst with Pt and transition metal-doped catalysts provides a new opportunity to design advanced hybrid catalysts for various electrocatalysis processes.