One-pot synthesis of pure phase molybdenum carbide (Mo2C and MoC) nanoparticles for hydrogen evolution reaction

Herein, we report the one-step synthesis of pure phase molybdenum carbide (Mo2C and MoC) nanoparticles via the in-situ carburization reduction route without using any reducing agent. The X-ray diffraction (XRD) results confirm the formation of pure phase Mo2C and MoC at 800 degrees C for 8 h and 15 h respectively. The as-synthesized powders have been investigated for hydrogen production and energy storage applications. The pure phase Mo2C shows high performance towards the hydrogen evolution reaction (HER) with a Tafel slope of 129.7 mV dec(-1) however, MoC exhibits a low activity towards HER with a Tafel slope of 266 mV dec(-1). Both the phases show high stability up to 5000 cyclic voltammetry (CV) cycles in the potential range of 0-0.4 V. In the case of MoC, the specific capacitance increases during the initial 2000 CV cycles which may be attributed to the electrode activation during the CV test. The Mo2C powder shows a double layer capacitance (C-dl) value of 2.47 mF cm(-2) and a specific capacitance of 2.24 mF g(-1). The MoC phase shows a higher C-dl value of 8.99 mF cm(-2) and a specific capacitance of 8.17 mF g(-1). (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.