Ce-doped NiFe layered double hydroxide coated NiMoOxS4−x compounds: an efficient OER catalyst in alkaline solution

Abstract

It is of great significance to develop stable, high performance and low cost OER catalysts to solve the energy crisis in the future. In this work, NiMoO_xS_4−x nanorods with oxygen defects were prepared on nickel foam as a conductive substrate, and then Ce doped NiFe LDH microspheres were combined on the surface to form a unique core–shell structure. At the current density of 100 mA cm⁻², the overpotential in 1 M KOH was 190 mV. The Tafel slope was only 37.1 mV dec⁻¹. The prepared OER catalyst showed excellent electrochemical performance. The unique structure increased the number of active sites and could adsorb more oxygen-containing intermediates. At the same time, abundant high energy amorphous states and defect sites were generated due to the Ce doping, which can increase the charge transfer rate. In addition, the strong electron coupling and synergistic effect existing between the Ce-NiFe LDH and NiMoO_xS_4−x can also accelerate the OER dynamics, enabling the rapid formation and release of bubbles. These results indicate that exploring the effect of lanthanide metal doping on OER performance is successful, providing a plan for achieving the hydrogen energy economy in the future.