School of Chemistry and Chemical Engineering, State Key Laboratory of Metal Matrix Composites, Shanghai Key Laboratory of Electrical Insulation and Thermal Ageing, Shanghai Jiao Tong University , 200240 Shanghai, P. R. China.
School of Electronic Information and Electrical Engineering, School of Aeronautics and Astronautics, Shanghai Jiao Tong University , 200240 Shanghai, P. R. China.
ACS Nano. 2017 Apr 25;11(4):3933-3942. doi: 10.1021/acsnano.7b00365. Epub 2017 Mar 20.
Molybdenum carbide (MoC) based catalysts were found to be one of the most promising electrocatalysts for hydrogen evolution reaction (HER) in acid media in comparison with Pt-based catalysts but were seldom investigated in alkaline media, probably due to the limited active sites, poor conductivity, and high energy barrier for water dissociation. In this work, MoC-embedded nitrogen-doped porous carbon nanosheets (MoC@2D-NPCs) were successfully achieved with the help of a convenient interfacial strategy. As a HER electrocatalyst in alkaline solution, MoC@2D-NPC exhibited an extremely low onset potential of ∼0 mV and a current density of 10 mA cm at an overpotential of ∼45 mV, which is much lower than the values of most reported HER electrocatalysts and comparable to the noble metal catalyst Pt. In addition, the Tafel slope and the exchange current density of MoC@2D-NPC were 46 mV decade and 1.14 × 10 A cm, respectively, outperforming the state-of-the-art metal-carbide-based electrocatalysts in alkaline media. Such excellent HER activity was attributed to the rich MoC/NPC heterostructures and synergistic contribution of nitrogen doping, outstanding conductivity of graphene, and abundant active sites at the heterostructures.
碳化钼（MoC）基催化剂被发现是在酸性介质中比 Pt 基催化剂更有前途的析氢反应（HER）电催化剂之一，但在碱性介质中很少被研究，这可能是由于活性位点有限、导电性差以及水离解的能垒高。在这项工作中，在一种简便的界面策略的帮助下，成功地实现了嵌入氮掺杂多孔碳纳米片的碳化钼（MoC@2D-NPCs）。作为碱性溶液中的 HER 电催化剂，MoC@2D-NPC 表现出极低的起始电位约为 0 mV 和在 45 mV 的过电势下电流密度为 10 mA cm，这远低于大多数报道的 HER 电催化剂的值，与贵金属催化剂 Pt 相当。此外，MoC@2D-NPC 的塔菲尔斜率和交换电流密度分别为 46 mV decade 和 1.14 × 10 A cm，优于碱性介质中最先进的金属碳化物基电催化剂。这种优异的 HER 活性归因于丰富的 MoC/NPC 异质结构以及氮掺杂、石墨烯的优异导电性和异质结构中丰富的活性位点的协同贡献。
