Phosphorus‐Doping‐Induced Optimization of Atomic Hydrogen Binding Energy in MoSe2 under High Coverage for Efficient Electrocatalytic Hydrogen Evolution Reactions

Abstract

AbstractSelf‐standing two‐dimensional P‐doped molybdenum diselenide (MoSe2) nanosheets were synthesized on carbon fiber paper (CFP) (P‐doped MoSe2/CFP) using a hydrothermal reaction followed by phosphorization and were subsequently used as a high‐efficiency hydrogen evolution reaction (HER) electrocatalyst. Nanosheet aggregation was remarkably inhibited, and numerous active sites were exposed. The H adsorption and desorption capacities of MoSe2 were optimized by doping P atoms in the MoSe2 lattice. Electrochemical testing indicated that the overpotential (η50) required by P‐doped MoSe2/CFP was only 186 mV, which was much lower than that of the as‐prepared MoSe2/CFP (237 mV). The Tafel slope of P‐doped MoSe2/CFP was 54.3 mV ⋅ dec−1, which was remarkably lower than that of the as‐prepared MoSe2/CFP (79.8 mV ⋅ dec−1). The Gibbs energy of the H atoms adsorbed on P‐doped MoSe2 (ΔGH*) reached the lowest value (0.202 eV) when the hydrogen coverage (θH) was 75 %. For MoSe2, the lowest ΔGH* value was 0.296 eV when θH was 25 %. The adsorption and desorption of H atoms at the active sites of P‐doped MoSe2 occurred easier than at the active sites of MoSe2. Moreover, the P doping effect facilitated the formation of more Hads species during the Volmer reaction and substantially accelerated the kinetics of the HER.