Sabhapathy P.Shown I.Sabbah A.Raghunath P.Chen J.-L.Chen W.-F.Lin M.-C.Chen K.-H.Chen L.-C.LI-CHYONG CHEN2022-08-092022-08-09202122112855https://www.scopus.com/inward/record.uri?eid=2-s2.0-85095432168&doi=10.1016%2fj.nanoen.2020.105544&partnerID=40&md5=6ad700453a86fbcfac7754c494c7f9d2https://scholars.lib.ntu.edu.tw/handle/123456789/616370Exploring an efficient platinum group metal (PGM) free electrocatalyst with superior activity and stability for hydrogen evolution reaction (HER) in a wide pH range is desirable for low-cost hydrogen production. Here, we report atomically dispersed cobalt on nitrogen and sulfur co-doped graphene (N-Co-S/G) for HER. Remarkably, the prepared N-Co-S/G electrocatalyst shows a small overpotential of 67.7 mV vs. reversible hydrogen electrode (RHE) at a current density of 10 mA cm−2 and exceptional durability over 100 h at 10 mA cm−2 under acidic conditions. Moreover, we found that the HER activity of N-Co-S/G is close to 20% Pt/C at all pH levels (0–14) and superior activity at high current density (>100 mA cm−2). Experimental and theoretical calculations reveal that the S atom in N-Co-S/G form Co-S bond, resulting new Co-N3S1 active site, which optimizes Gibbs free energy for hydrogen adsorption (∆GH*) close to zero, while water adsorption and dissociation enhanced by S modulation for neutral and basic media HER. © 2020 Elsevier LtdAtomic cobalt;Electronic structure;Graphene;Hydrogen evolution reaction (HER);Nitrogen and sulfur co-doped;Nonprecious electrocatalyst[SDGs]SDG7Electrocatalysts;Electronic structure;Free energy;Gas adsorption;Gibbs free energy;Hydrogen production;Modulation;Sulfur;Acidic conditions;High current densities;Hydrogen adsorption;Platinum group metals;Reversible hydrogen electrodes;Theoretical calculations;Water adsorption;Wide pH range;Hydrogen evolution reactionjournal article10.1016/j.nanoen.2020.1055442-s2.0-85095432168