MoP-Mo2C quantum dot heterostructures uniformly hosted on a heteroatom-doped 3D porous carbon sheet network as an efficient bifunctional electrocatalyst for overall water splitting

[Display omitted] •MoP-Mo2C quantum dot heterostructures uniformly distribute on carbon sheet network.•MoP-Mo2C/NPC possesses abundant heterogeneous interfaces and pore structure.•MoP-Mo2C/NPC exhibits low overpotentials and ultrahigh stability for HER and OER. In this work, we constructed MoP-Mo2C quantum dot heterostructures uniformly hosted on a three-dimensional (3D) hierarchically porous thin N,P-doped carbon sheet network (MoP-Mo2C/NPC) by a novel one-pot simultaneous phosphating-carbonization-activation of molybdenum-chelated resin and KOH. Chelate confinement not only prevents the aggregation of MoP/Mo2C quantum dots, but also synchronously produces a carbon sheet network doped with N and P without the requirement for post-atom doping. The prepared MoP-Mo2C/NPC exhibited a large specific surface area, a high electron conductivity, and abundant active sites for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER). As a result, MoP-Mo2C/NPC with a low calculated Gibbs free energy for H adsorption exhibited an excellent electrocatalytic activity and an ultrahigh stability for both the HER and OER processes in an alkaline medium. In addition, the assembled MoP-Mo2C/NPC || MoP-Mo2C/NPC alkaline electrolyzer delivered a current density of 10 mA cm−2 at an overpotential of only 1.55 V, and maintained > 95% of the initial current density after 168 h (1 week) of activity, which is superior to that of the state-of-the-art Pt/C || RuO2/C system in the overall water splitting process.