The development of low-cost and highly active electrocatalysts for two half reactions: H2 and O2 evolution reactions (HER and OER), is still a huge challenge to realize water splitting. Herein, we report that CoP nanoparticles (NPs) can act as a bi-functional catalyst for both HER and OER. Particularly, ultrafine CoP NPs decorated on N-doped multi-walled carbon nanotube (MWCNT) exhibit remarkable catalytic performance for OER in 0.1 M NaOH aqueous solution, with a low onset overpotential of 290 mV, a Tafel slope of 50 mV dec?1 , an overpotential (η) of 330 mV at 10 mA cm?2 and, approximately 100% Faradic efficiency, paralleling the performance of state-of-the-art Co-based OER catalysts including Co3O4, CoSe2 and Co-Pi. The hybrid catalyst is capable of maintaining a high catalytic current density for at least 10 h without any loss of catalytic activity. Meanwhile, the noble-metal-free catalyst also shows good activity and duarability for HER under the same basic condition.

ACS Appl. Mater., 2015