Completely reconfigured Fe1-xS/C ultra-thin nanocomposite lamellar structure for highly efficient oxygen evolution

The surface reconfiguration of electrocatalysts during oxygen evolution reaction (OER) is much more important to reveal the actual catalytic active species, thus realizing the optimization of electrocatalyst activity. Herein, we demonstrate a simple strategy to achieve the complete electrochemical reconfiguration of Fe1-xS nanocrystals/ultra-thin carbon (Fe1-xS NCs/@ UT-C) nano-lamellar structure during the OER process. The uniform dispersion of Fe1-xS nanocrystals on the ultra-thin carbon layer favors the rapid complete reconfiguration. Such rapid reconfiguration creates new actual catalytic active species of amorphous iron-based oxide transformed from Fe1-xS, which is coupled with an ultra-thin carbon layer to facilitate the charge transfer of OER. More detailed, partly graphitization of the ultra-thin carbon layer not only affords to overcome the ohmic losses but also enhances the overall electrical conductivity and OER activity of the material. The Fe1-xS NCs/@UT-C as pre-catalyst shows high OER activity with a low overpotential of only 303 mV at 100 mA cm−2 and a Tafel slope of 55 mV/dec. In addition, the reconfigured catalyst has good stability for 168 h in alkaline conditions. This work is beneficial to understand the reconfiguration of electrocatalysts and design high-efficiency nonprecious metal-based electrocatalysts.