Preparation of Ni-P-CeO2 electrode and study on electrocatalytic properties for hydrogen evolution reaction

In this study ternary Ni-P-CeO2 catalysts were first synthesized by the Co-electrodeposition method on a copper substrate and then characterized by means of microstructural and electrochemical techniques toward a hydrogen evolution reaction (HER). Also, for comparison other catalysts such as Ni-CeO2, Ni-P, and Ni were prepared and characterized by the same methods. The microstructure of the investigated catalysts was characterized by scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectrometry (EDX) and X-ray diffraction (XRD) methods. The electrochemical efficiency of all investigated catalysts was studied based on electrochemical data obtained from electrochemical impedance spectroscopy (EIS) and steady-state polarization Tafel curves in 1 M NaOH solution. The results showed that microstructural properties play an essential role in the high electrocatalytic activity of Ni-P-CeO2. Furthermore, it was observed that the HER mechanism for all investigated systems was Volmer-Heyrovsky with a Volmer step as the rate determining step (RDS). The Ni-P-CeO2 catalyst, as the most active catalyst in this work, was characterized by an exchange current density of j0=168.0 µAcm-2, a Tafel slope of b=-162.0 mV.dec-1, and overpotential at j0=250 mAcm-2; η250=-143.0 mV.