Oxygen vacancy-induced crystal-amorphous interface in NiFe LDH catalyst for enhanced OER performance

NiFe LDH exhibits excellent OER performance due to its unique layered structure. However, the limited density of active sites in NiFe LDH hinders further enhancement of OER performance. By introducing surface oxygen defects to modulate the surface functional groups and interfacial active sites of LDHs, the electrocatalytic reaction kinetics are effectively optimized. The introduced oxygen vacancies increase the interface active sites of the NiFe LDH catalysts, thereby improving the interfacial reaction rate and optimizing the catalytic performance. In this work, sulfate-intercalated NiFe 0.3 LDH with abundant oxygen vacancies was synthesized by a co-precipitation method. The abundant oxygen vacancy defects resulted in a reduction in long-range atomic order and crystallinity, leading to the formation of a crystal/amorphous structure. This structural modification optimized the mass transport process during OER, enhanced the electronic configurations of Ni and Fe, and improved their synergistic interactions, thereby increasing the catalytic activity. At a current density of 10 mA cm -2 , a low overpotential of 230 mV and a Tafel slope of 50.7 mV dec ‑1 were achieved. Furthermore, after 40 h of continuous cycling, the overpotential of the NiFe0.3 LDH sample exhibited minimal change. This work provides new insights into the rational synthesis of high-performance OER catalysts with vacancy defects using the co-precipitation method.