Decoupling hydrophilicity and superaerophobicity on amorphous molybdenum sulfide for high-rate water splitting

The development of water splitting electrocatalysts with earth-abundant materials capable of delivering high current density is crucial for sustainable H2 production. However, the mass transfer including reactants and bubbles usually suffered from the shielding effect of gas adhesion under such circumstance. Here, we report a surface engineering strategy over amorphous molybdenum sulfide (a-MoSx) to synergistically boost its generation and departure of gas bubbles. To begin with, a hydrophilic surface featuring hydroxy groups was constructed via palladium−doping induced sulfur vacancies on a-MoSx, which could enhance the local access of aqueous reactant. Furthermore, the departure of gas bubbles could be accelerated by regulating the roughness of the synthesized Pd-MoSx(OH)y nanoarrays. For demonstration purpose of practical applications, the bifunctional Pd-MoSx(OH)y nanoarrays could deliver a high current density of 1000 mA cm−2 at 1.99 V for overall water splitting over 100 h.