Ultra-dispersed molybdenum phosphide and phosphosulfide nanoparticles on hierarchical carbonaceous scaffolds for hydrogen evolution electrocatalysis

Transition metal phosphides are arguably the most promising non-precious metal-based materials for hydrogen evolution reaction (HER). Unfortunately, their high preparation temperature usually results in particle sintering. It is challenging to achieve the ultra-dispersion of transition metal phosphide nanoparticles on conductive supports so as to enlarge their surface areas and reinforce their physical stability. In this study, we prepare fine MoP nanoparticles uniformly dispersed on hierarchical carbonaceous scaffolds by using strongly interacting Mo, P and C precursors. The resultant hybrid product possesses a three-dimensional open structure that allows a large fraction of MoP nanoparticles electrochemically accessible and suppresses their possible agglomeration during extended electrocatalysis. Electrochemical measurements show that the product has an impressive HER activity, only requiring an overpotential of 120 and 170 mV to achieve 10 mA/cm2 in 0.5 M H2SO4 and 1M KOH, respectively, as well as great cycling stability. Its performance can be further promoted via the controlled sulfur doping at surface to form molybdenum phosphosulfide, which reduces the overpotential at j = 10 mA/cm2 to 92 mV and 158 mV for acidic and alkaline HER.