Oxygen evolution over Fe1/NiSe2 single-atom electrocatalyst: The role of thermal-electrical cascade and surface reconstruing

Oxygen evolution reaction (OER) in water electrolysis is a tough challenge. Here we report the thermally activated on-surface oxygen evolution at nickel diselenide under alkaline conditions, specifically focusing on the (101) and (100) facets supported with Fe single-atom electrocatalysts. Assisted by heat, the Fe₁/NiSe₂(101) and (100) facets demonstrate highly efficient activity for oxygen evolution at pH = 14. First-principles calculations and AIMD simulations illustrate excellent electrical conductivity and thermal stability of the Fe₁/NiSe₂(101) and (100) facets, as well as provide a promising understanding of electron transports among the oxygen-containing active species and the electrocatalysts during thermal-electrical cascade of OER under alkaline conditions. The enhanced OER performance depends on the co-adsorbate combinations: *O_(Fe-Se^Ⅰ₎-*OH_(Se^Ⅱ₎ and *O_(Fe-Se^Ⅰ₎-*OH_(Ni) at the Fe₁/NiSe₂(101) facet, whose adsorption behaviors lead to self-activated surface reconstruing. Impressively, the affinity of the key intermediates at the potential-determining steps of OER: *O_(Fe-Se^Ⅰ₎ at the Fe₁/NiSe₂(101) facet, *O_(Fe) and *OOH_(Fe) at the Fe₁/NiSe₂(100) facet, is optimized by such self-activated surface reconstruing.