Cobalt phosphide nanofibers derived from metal-organic framework composites for oxygen and hydrogen evolutions

The fabrication of one-dimensional (1D) nanocatalysts with high active surface areas is very important to the development of high-performance catalysts but challenging. Through the phosphidation of metal-organic framework (MOF) nanofiber (NF) composites, bifunctional cobalt phosphide NFs (CoP NFs) which showed a diameter of about 100 nm and length of several micrometers as well as a large catalytic surface area were successfully fabricated and used as the electrocatalysts for water splitting. Taking the advantage of this MOF-derived strategy, a series of 1D nanostructures including Co3O4 NFs, and carbon NFs immobilized with CoP or Co nanoparticles were also synthesized and investigated. The density of active sites and catalytic performances of CoP NFs could be improved by the modulation of Cu-related species. The uniform Cu-doped CoP NFs showed the best catalytic performances for both oxygen and hydrogen evolutions with the overpotentials of 330 and 170 mV, respectively, which are comparable to those of commercial noble-metal catalysts. This work provides a facile process to fabricate 1D bifunctional electrocatalysts with desired functionalities for energy-related applications.