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

• Published in: Chemical engineering journal (Lausanne, Switzerland : 1996) Vol. 431; p. 133719
• Main Authors: Jiang, Enjun, Li, Junqing, Li, Xiaolan, Ali, Asad, Wang, Guifang, Ma, Shaojian, Kang Shen, Pei, Zhu, Jinliang
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01-03-2022
• Subjects: Heterostructure; Molybdenum carbide; Molybdenum phosphide; Overall water splitting; Porous carbon; Quantum dot; Heterostructure; Quantum dot; Molybdenum phosphide; Porous carbon; Molybdenum carbide; Overall water splitting
• ISSN: 1385-8947; 1873-3212
• DOI: 10.1016/j.cej.2021.133719

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•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.