Fe₅Ge₂Te₂: Iron‐rich Layered Chalcogenide for Highly Efficient Hydrogen Evolution

Abstract

Recent research on van der Waals (vdW) metal chalcogenides electrocatalysts for the hydrogen evolution reaction (HER) has been devoted to finding new catalysts with active basal planes. Here, we report on experimental and theoretical investigations of the HER activity of a recently discovered iron‐rich vdW spintronic material, Fe5Ge2Te2 (FG2T) in alkaline media (1 M KOH). We show that a densified electrode of FG2T requires an overpotential of only −90.5 mV to drive a current density of 10 mA/cm2. Free energy calculations of hydrogen adsorption using density functional theory (DFT) proved that the numerous sites present on the hexagonal Te layer are more active than those found in the recently proposed Fe3GeTe2 (FGT) catalyst, supporting higher activity for the new Fe‐richer catalyst. Like in FGT, XPS analysis has found that a thin oxide layer covers the active FG2T layers, suggesting the real active surface to be a hybrid FG2T/oxide layer. These results strengthen the idea of continued screening of iron‐based vdW materials to replace the non‐abundant platinum group electrocatalysts toward HER and other electrocatalytic processes.