PANI-coated porous FeP sheets as bifunctional electrocatalyst for water splitting

Polyaniline (PANI) coated porous iron phosphide (PANI/p-FeP) supported on nitrogen‑doped carbon fiber/carbon paper (PANI/p-FeP/NCF/CP) is prepared as a high efficient electrocatalyst for water splitting. The synergistic effect between PANI coating and underlying porous FeP not only affords richly exposed active sites, but also modulates the electronic structure of FeP and thus accelerates the charge or mass transfer efficiency, which eventually improves the catalytic activity. The self-supported PANI/p-FeP/NCF/CP composite requires low overpotentials of 59 and 76 mV at 10 mA cm−2 current density in 0.5 M H2SO4 and 1.0 M KOH for hydrogen evolution reaction (HER). Otherwise, PANI/p-FeP/NCF/CP only requires an overpotential of 355 mV at 10 mA cm–2 in 1.0 M KOH for oxygen evolution reaction (OER). PANI/p-FeP/NCF/CP exhibits good durability for HER and OER due to the protective effect of PANI coating in the electrochemical process.