Carbon nanofibers as nanoreactors in the construction of PtCo alloy carbon core-shell structures for highly efficient and stable water splitting

Carbon nanofibers served as nanoreactors for the design and construction of PtCo alloy carbon core-shell nanostructures with nitrogen doping (PtCo/NCNF) through a combination of electrospinning and nitrogen doping treatments. The PtCo/NCNF hybrid consists of PtCo alloy nanoparticles surrounded by a few of N-doped carbon layers , demonstrating a typical core-shell structures. The PtCo/NCNF hybrid can both served as electrode materials for electrocatalytic water splitting including hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). For the HER performance, the PtCo/NCNF exhibits very small onset potential of 20   mV, an overpotential of 50   mV at a j (vs RHE)   =   10   mA   cm −   2 and Tafel slope of 30   mV   dec −   1 . The PtCo/NCNF hybrid also exhibits high OER activity with an onset potential of 310   mV, an overpotential of 400   mV at a j of 10   mA   cm −   2 and a small Tafel slope of 76   mV   dec −   1 . The high catalytic activities of PtCo alloy for HER and OER originate from the 3D hierarchical structures, well-dispersed PtCo alloy, high conductivity of NCNF, protection from the carbon-encapsulated structure, and the introduction of nitrogen.