Non-layered dysprosium oxysulfide as an electron-withdrawing chainmail for promoting electrocatalytic oxygen evolution

Rare-earth doping is an efficient strategy to elevate the oxygen evolution reaction activity of transition-metal-based electrocatalysts, yet it often leads to deleterious electrochemical corrosion. Here, we introduce non-layered dysprosium oxysulfide (Dy2O2S) to a cobalt catalyst to address this issue. Benefiting from an electron-withdrawing Dy2O2S shell, the optimum chainmail-structured catalyst displays low overpotentials of 225 ± 1 and 299 ± 5 mV at 0.1 and 1.0 A·cm−2, respectively, for the oxygen evolution reaction under industrially relevant conditions. Moreover, Dy2O2S blocks the dissolution of dysprosium and cobalt, endowing the catalyst with almost 100% activity retention for at least 120 h at 1 A·cm−2. A variety of in situ/ex situ characterization techniques and theoretical calculations unveil the active sites and the interfacial electron redistribution, which facilitate the oxygen intermediate adsorption and oxygen desorption. This work provides a route to utilize rare-earth elements to optimize the performance of electrocatalysts. [Display omitted] •Chainmail-structure dysprosium oxysulfide/cobalt catalysts are synthesized•Catalysts achieve ampere-level current density for oxygen evolution reaction•Dysprosium oxysulfide shell blocks the dissolution of metals under industrial conditions•The electron-withdrawing nature of dysprosium in the electrocatalyst is unveiled A core-shell-structured dysprosium-containing catalyst is reported that features robust dysprosium oxysulfide chainmail to protect cobalt during electrocatalytic oxygen evolution. Zhang et al. show that interfacial electron redistribution between the shell and core alters intermediate adsorption energy, endowing stability at ampere-level current density under industrially relevant conditions.