El-Refaei, S.M.; Russo, P.A.; Schultz, T.; Koch, N.; Pinna, N.: Dual Doping of MoP with M(Mn,Fe) and S to Achieve High Hydrogen Evolution Reaction Activity in Both Acidic and Alkaline Media. ChemCatChem 13 (2021), p. 4392-4402
10.1002/cctc.202100856
Open Access Version
Abstract:
Rational design of cost-effective, high performance and stable hydrogen evolution reaction (HER) electrocatalysts in both acidic and alkaline media holds the key to the future hydrogen-based economy. Herein, we introduce an effective approach of simultaneous non-metal (S) and metal (Fe or Mn) doping of MoP to achieve excellent HER performance at different pH. The catalysts show remarkable overpotentials at -10 mA cm-2 of only 65 and 68 mV in 0.5 M H2SO4, and 50 and 51 mV in 1.0 M KOH, respectively, as well as much higher turnover frequencies compared to undoped MoP. Furthermore, the catalysts exhibit outstanding long-term stability at a fixed current of -10 mA cm-2 for 40 h. The effects of both dopants, such as electronic structure modification and enhancement of the intrinsic activity, increase of the electrochemically active surface area, and formation of coordinatively unsaturated edge sites, act cooperatively to accelerate the HER at both pH media. Additionally, the presence of oxophilic Mn and Fe at the surface results in Mn or Fe oxide/hydroxide species that promote the dissociation of water molecules in alkaline electrolyte. This work introduces a facile and effective design principle that could pave the way towards engineering highly active HER catalysts for a wide pH range.