Molybdenum Carbide Electrocatalyst/Support Synthesis and Characterization

Abstract

Transition metal carbides are increasingly gaining attention as electrocatalysts/supports due to their unique properties including structural durability, electronic conductivity, and an electron structure which is somewhat similar to that of noble metals[1]. Molybdenum carbide has shown to be an active catalyst and as a noble metal support, however it is difficult to prepare in high surface area nanoparticle form[2,3]. Most nanoparticle synthesis methods produce residual carbon that blocks surface access. In order to improve materials performance, high surface area, impurity-free molybdenum carbides are needed. With the aid of thermochemical modeling and gas equilibration studies, we have developed a synthesis method that yields high surface area MoC nanoparticles of the metastable cubic phase. These 2-3 nm MoC nanoparticles have surface areas of up to 360m2/g and have been characterized using TEM, XRD, EDS, XPS, and BET. The nanoparticles were tested for their effectiveness for both electrochemical and heterogeneous synthesis of ammonia. [1] Y. Liu, T.G. Kelly, J.G. Chen, W.E. Mustain, Metal Carbides as Alternative Electrocatalyst Supports, ACS Catal. 3 (2013) 1184–1194. doi:10.1021/cs4001249. [2] M. Patel, J. Subrahmanyam, Synthesis of nanocrystalline molybdenum carbide (Mo2C) by solution route, Materials Research Bulletin. 43 (2008) 2036–2041. doi:10.1016/j.materresbull.2007.09.025. [3] A.M. Gomez-Marin, E.A. Ticianelli, Analysis of the electrocatalytic activity of a-molybdenum carbide thin porous electrodes toward the hydrogen evolution reaction, Electrochimica Acta. 220 (2016) 363–372. doi:10.1016/j.electacta.2016.10.101. Figure 1