Fabrication of Fe-doped Co2P nanoparticles as efficient electrocatalyst for electrochemical and photoelectrochemical water oxidation

Abstract

Fe-doped Co2P nanoparticles (Fe-Co2P) are successfully synthesized using a facile and scalable solid reaction method and demonstrate highly efficient oxygen evolution reaction (OER) activity towards water splitting. Benefiting from the synergistic effect of Fe, Co and P as well as enlarged electrochemical active surface area (ECSA), the resultant Fe-Co2P nanoparticles yield extraordinary OER performance with an overpotential as low as 289 mV at 10 mA cm−2, a small Tafel slope of 40 mV dec−1, and excellent OER stability, which are superior to the individual Co2P, Fe2P as well as the commercial RuO2 electrocatalyst. Moreover, Fe-Co2P nanoparticles are also shown to be a resultful co-catalyst to promote the photoelectrochemical (PEC) water oxidation performance of α-Fe2O3 photoanode, leading to a cathodic potential shift of ∼200 mV at 1.0 mA cm−2 and a significantly promoted photocurrent density of 1.40 mA cm−2 at 1.23 VRHE with respect to that of bare α-Fe2O3. The effective synthesis method and electronic modulate-induced enhancement of OER by hetero-atom doping highlight the promising design and fabricate of various efficient bimetallic or polymetallic phosphides for photo-/electrochemical water splitting.