Tungsten-doped cobalt-iron bimetallic phosphide nanoparticles for enhanced oxygen evolution reaction

Abstract

BackgroundHydrogen obtained from electrochemical water splitting is an efficient method for hydrogen production, which is urgent to develop high efficiency electrocatalyst and commercialize the process. MethodsIn our work, we used coprecipitation, doping and phosphating strategies to report the trimetallic Prussian blue analogue precursors (W-CoFe PBA) were prepared by doping sodium tungstate into cobalt-iron-Prussian blue analogues (CoFe PBA), and then by a low temperature phosphating treatment to obtain tungsten doped cobalt-iron phosphide (W-CoP/FeP) heterostructures. This strategy of doping and then phosphating can allow the charge distribution is adjusted, the conductivity is increased, the electron transport to the surface is accelerated, and the synergistic effect between CoP and FeP is enhanced. Significant findingsThe experimental results show that the mass ratio of tungsten source to CoFe-PBA is 0.5 (0.5W-CoP/FeP), which shows outstanding activity with overpotentials of 282 mV for the oxygen evolution reaction (OER) in 1 M KOH at a current density of 10 mA cm−2 and Tafel slope of 29.14 mV dec−1. Simultaneously, it also exhibits excellent stability for 24 h in the chronopotentiometry test. This work provides a simple improvement for the application of Prussian blue analogues in the electrochemical water splitting.