La/Ce doped CoFe Layered double hydroxides (LDH) highly enhanced oxygen evolution performance of water splitting

Abstract The design of a new, low-cost, high-efficiency and stable oxygen evolution reaction catalyst is of great significance to water electrolysis technology. In this paper, La-doped and Ce-doped CoFe LDH was prepared to enhance OER. Experiments show that the OER performance with 25%La-CoFe LDH and 25%Ce-CoFe LDH is better than CoFe LDH. And the oxygen evolution potential of 25%La-CoFe LDH at a current density of 10 mA/cm2 is 1.547 V, which is far lower than CoFe LDH(1.694 V). And it also has lower Tafel slope(125 mV/dec), larger electrochemical specific surface area(2.46mF/cm2) and lower charge transfer resistance(37.5 Ω). Through a series of characterization test analysis, it can be concluded that after La3+ or Ce3+ partially replaces Fe3+, the CoFe LDH system has more defects. This may be due to the fact that the ionic radius of La3+ and Ce3+ is much larger than that of Fe3+, and La3+ and Ce3+ have unique electronic structures. The partial replacement of Fe3+ will affect the electronic structure of CoFe LDH, thereby enhancing the electronic coordination in the system, thereby exhibiting excellent OER performance.