Ce dopant regulating oxygen vacancy of medium-entropy NiCoFe-LDH for efficiently enhancing urea-assisted electrolytic hydrogen production

The fabrication of advanced electrocatalysts for urea-assisted electrolytic water splitting is of great significance for yielding green hydrogen. In this study, Ce doping a quaternary sea urchin like medium-entropy NiCoFe layered double hydroxide (Ce 1.2 -NiCoFe-LDH) nanoshe et s were obtained by employing a doping engineering strategy. Characterization experimental results confirmed that Ce dopants could modify the oxygen vacancy structure of NiCoFe-LDH, accelerating charge and mass transfer. thereby enhancing the urea decomposition. The electrochemical results indicated that Ce 1.2 -NiCoFe-LDH demonstrated high-efficiency catalysis for UOR, characterized by high intrinsic activity, rapid kinetics, and robust durability. The overpotential of Ce 1.2 -NiCoFe-LDH was only 48 mV at the current density of 10 mA cm −2 , much lower than the commercial IrO 2 (126 mV at 10 mA cm −2 ). The tafel slope of Ce 1.2 -NiCoFe-LDH (62 mV dec −1 ) was also better than those of IrO 2 (88 mV dec −1 ) and NiCoFe-LDH (99 mV dec −1 ). Compared with the commercial IrO 2 , the Ce 1.2 -NiCoFe-LDH exhibited a change of only 3.2 % after a 12-hour chronoamperometric test, indicating an improvement in stability. Impedance comparison between the two hydrotalcites revealed that Ce 1.2 -NiCoFe-LDH possessed lower impedance, potentially enhancing catalytic efficiency. Therefore, this work illustrates that the modulation of oxygen vacancies in electrocatalysts, induced by the heteroatom doping effect, can enhance the electrocatalytic oxidation performance of small molecules for hydrogen production.