In Situ Catalytic Etching Strategy Promoted Synthesis of Carbon Nanotube Inlaid with Ultrasmall FeP Nanoparticles as Efficient Electrocatalyst for Hydrogen Evolution

The development of effective methods for synthesizing and stabilizing ultrafine supported metal catalysts is not only advantageous but significantly recommendable in electrocatalytic water splitting. Herein, carbon nanotube inlaid with ultrasmall FeP nanoparticles is engineered by a controlled in situ catalytic carbon etching strategy. The key for implementing this favorable effect lies in the close self-assembly of iron(II) phthalocyanine onto carbon nanotube by pi-pi stacking interactions. During the pyrolysis process of the assemblies in the air, the generated ultrasmall Fe2O3 nanoparticles stemming from iron(II) phthalocyanine can synchronously in situ catalyze the decomposition of the adjacent carbon nanotube, which makes Fe2O3 nanoparticles tightly anchor onto, and/or even infiltrate into, the carbon nanotube. Subsequently, the inlaid ultrasmall FeP nanoparticles are obtained by a facile anion-exchanging process. Thanks to the more accessible active sites, inlaid structure, and superior electrical conductivity originating from the interconnected carbon nanotube, the as-obtained hybrid exhibits superior electroactivity toward hydrogen evolution reaction, achieving a very low overpotential (68 mV at 10 mA cm(-2)), favorable reaction kinetics, and remarkable stability. The present strategy provides a novel method for strengthening the interactions between ultrasmall catalyst particles and the conductive supports for achieving efficient and robust catalysts toward energy storage and conversion systems.