2219
Self-Assembly- and Preshaping-Assisted Synthesis of Ultrathin Nitrogen-Doped Graphitic Carbon Lamellas Supported Molybdenum Carbide for Hydrogen Evolution Reaction

Tuesday, 3 October 2017
Prince George's Exhibit Hall D/E (Gaylord National Resort and Convention Center)

ABSTRACT WITHDRAWN

The sustainable generation of hydrogen through water electrolysis by using electricity has attracted great attention but remains an elusive goal in catalysis. Metallic carbide have been ardently expected to be the most promising alternatives to replace or reduce Pt employment in electro-catalyze HER.[1,2] Herein, we report a “self-assembly and preshaping” strategy for the controllable synthesis of porous graphitic carbon lamellas supported highly dispersed Mo2C nanoparticles (Fig. 1a-c). The self-assembly and preshaping not only efficiently promoted the distribution of Mo2C on the highly conductive carbon nanolamellas, but it also impeded the aggregation and excessive growth of ultrafine Mo2C nanoparticles at high temperatures. These features enabled the full exposure and utilization of the Mo2C active sites for H+ adsorption and reduced the electrical resistance between neighboring surface-Mo2C, endowing the constructed Mo2C/C-lamellas with a superior HER activity and long-term stability compared with traditional bulk Mo2C/C. As a matter of course (Fig. 1d-g), relative to traditional Mo2C/C-bulks, the as-constructed Mo2C/C-lamellas exhibits higher activity for the HER with a lower onset overpotential (145 mV), a smaller Tafel slope (60.5 mV dec-1), better electroconductivity, and improved stability over 20 h during operation in 0.5m H2SO4. This self-assembly and preshaping assisted carburization method represents a rational strategy for the preparation of robust carbon composite materials with hierarchically ordered structures, especially high melting point and easily-aggregation compound.

Figure 1. (a) Schematic illustration of the synthetic procedure of Mo2C/C lamellas; (b,c) TEM images of Mo2C/C lamellas; (d,e) Linear Sweep Voltammetry curves and Tafel plots during HER over 20 wt% Pt/C, SA-C, Mo2C/C bulks and Mo2C/C lamellas; (f) Current density vs. time (I–t) curve of HER over Mo2C/C lamellas at I=10 mA over 20 h-long electrocatalytic reaction; (g) Polarization curves of Mo2C/C lamellas before and after ageing.

Reference:

[1] M. S. Dresselhaus, I. L. Thomas, Nature 2001, 414, 332-337.

[2] W.-F. Chen, J. T. Muckerman, E. Fujita, Chemical communications 2013, 49, 8896.