“…Over the past decade, the binary selenide compounds ( e.g ., FeSe 2 , MoSe 2 , WSe 2 , etc. ) display unique structures of the center metal atoms octahedrally bonded with adjacent selenium atoms, which are considered promising alternatives to Pt-based electrocatalysts owing to their affordable price and good electrocatalytic effects. − In particular, FeSe 2 nanocrystals with high natural abundance commonly exhibit a series of textural advantages, including thermodynamic stability, environmental friendliness, stable configuration, and superior electrocatalytic properties, all of which are highly desirable for the HER. − However, the bare FeSe 2 with low electrical conductivity lacks sufficient reactive centers due to the inherent stacking arising from the high surface energy, which are unable to make full use of electrochemical activity and eventuates in a poor conductivity of the catalytic system. , …”