CeO2/FeS2 embedded in nitrogen doped carbon with mosaic structure: An effective catalyst for oxygen evolution reaction

Background: Reasonably designed non-precious metal catalysts for efficient oxygen evolution reaction (OER) are important for energy storage devices.Methods: Herein, a novel sol-gel method was proposed to obtain polyoxazine nanospheres, it was cleverly syn- thesized. Then, Ce3+and Fe3+modified the nanospheres by hydrothermal and high-temperature pyrolysis. CeO2/ Fe3O4/N-C was successfully prepared by solvothermal and high temperature pyrolysis, following, CeO2/Fe3O4/ N-C is modified with thioacetamide (TAA) to give CeO2/FeS2/N-C (5:1). Therefore, CeO2/FeS2/N-C (5:1) was obtained. The variability of valence states between the same metals is seen as a key factor in speeding up electron transport.Significant findings: In 1 M KOH, the optimal metal ratio CeO2/FeS2/N-C (5:1) expresses a lower overpotential of 340 mV@100 mA cm-2 than that of RuO2 (eta=382 mV@100 mA cm-2). Moreover, interestingly, successful doping of sulfur element is considered a key means to modify the OER catalytic activity of CeO2/Fe3O4/N-C. S is subsequently doped into the CeO2/Fe3O4/N-C lattice to increase the M3+/M2+ molar ratio (M=Fe and Ce), promote reaction kinetics, and optimize the electronic structure.