First-principles study of the oxygen evolution reaction on Ni3Fe-layered double hydroxides surfaces with varying sulfur coverage

Abstract

Ni3Fe-layered double hydroxides (Ni3Fe-LDHs) are promising catalysts for the oxygen evolution reaction (OER). Recently, Ni3Fe (oxy) hydroxides incorporating S have demonstrated enhanced OER activity, but the effects of varying the S coverage have not been studied. The present work used first-principles calculations to explore the OER performance of Ni3Fe-LDH specimens with 1/4, 1/2 and 3/4 S monolayer coverage on their (110) surfaces. The performances of the three Ni3Fe-LDH with different S coverages were compared to that with a clean surface at both Ni and Fe sites. The overpotential values calculated for Ni sites decreased in the order of clean > 1/2 monolayer > 3/4 monolayer > 1/4 monolayer, while the values for Fe sites decreased in the order of clean > 3/4 monolayer > 1/2 monolayer > 1/4 monolayer. In addition, the overpotentials at Fe sites were determined to be lower than those at Ni sites for the same coverage. In the case of a 1/4 S monolayer coverage, the overpotential at Fe sites was as low as 153 mV. Comparison of the Bader charge values and partial density of states data between the O covered and S covered surfaces indicated that a surface with a 1/4 S monolayer readily adsorbed the reaction intermediate OH.