Electronic structure modulation of isolated Co-N4 electrocatalyst by sulfur for improved pH-universal hydrogen evolution reaction
- Citation:
- Sabhapathy, P, Shown I, Sabbah A, Raghunath P, Chen J-L, Chen W-F, Lin M-C, Chen K-H, Chen L-C. 2021. Electronic structure modulation of isolated Co-N4 electrocatalyst by sulfur for improved pH-universal hydrogen evolution reaction, 2021. Nano Energy. 80:105544.
Abstract:
Exploring 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.
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