Cobalt Phosphide Based Nanostructures as Bifunctional Electrocatalysts for Low Temperature Alkaline Water Splitting

摘要

Cobalt phosphide based thin films and nanoparticles were prepared by the thermal phosphidation of spinel Co_3O_4 precursor films and nanoparticles, respectively. CoP films were prepared with overall retention of the Co_3O_4 nanoplatelet morphology while the spherical/cubic Co_3O_4 and Ni_(0.15)Co_(2.85)O_4 nanoparticles were converted to nanorods or nanoparticles, respectively. The inclusion of nickel in the nanoparticles resulted in a 2.5 fold higher surface area leading to higher gravimetric performance. In each case high surface area structures were obtained with CoP as the primary phase. All materials were found to act as effective bifunctional electrocatalysts for both the HER and the OER and compared well to commercial precious metal benchmark materials in alkaline electrolyte. A symmetrical water electrolysis cell prepared from the CoP-based film operated at a low overpotential of 0.41-0.51 V.