Single‐Atom Nickel Encapsulated in Nanosheet‐Coiled rGO‐CTAB‐MoS2 Nanoflowers for High‐Efficiency and Long‐Term Hydrogen Evolution in Acidic Medium

Abstract Molybdenum disulfide (MoS 2 ) is a promising, cost‐effective alternative to noble metal catalysts for electrocatalytic hydrogen evolution reactions (HER). However, its poor conductivity and limited active sites hinder its application. In this study, single‐atom nickel (Ni SA) encapsulated in nanosheet‐coiled rGO‐cetyltrimethyl ammonium bromide (CTAB)‐MoS 2 nanoflowers is designed and synthesized using hydrothermal and photodeposition methods. The resulting Ni SA/rGO‐CTAB‐MoS 2 exhibited outstanding HER performance, with an overpotential of 79 mV and a Tafel slope of 33.28 mV dec −1 at a current density of 10 mA cm −2 in 0.5 m H 2 SO 4 . Notably, it demonstrates exceptional durability, maintaining performance for over 300 h at −0.828 V versus RHE. A milligram of the catalyst produced 1209.4 L of hydrogen under highly acidic conditions at ambient temperature and pressure, making it a viable alternative to commercial Pt/C catalysts. Experimental and theoretical investigations reveal that the interplay between Ni SA and the surrounding rGO‐CTAB‐MoS 2 significantly enhances active sites availability, intrinsic conductivity, structural stability, and favorable adsorption behavior of H atoms, thereby leading to exceptional HER performance. This work presents a promising approach to develop durable MoS 2 ‐based catalysts with excellent HER activity.