Honeycomb micro/nano-architecture of stable β-NiMoO_4 electrode/catalyst for sustainable energy storage and conversion devices

摘要

Multi-functionality is a highly desirable feature in designing new electrode material for both energy storage and conversion devices. Here, we report a well-integrated and stable beta-NiMoO4 that was fabricated on three dimensional (3D) nickel foam (NF) by a simple hydrothermal approach. The obtained beta-NiMoO4 with interesting honeycomb like interconnected nanosheet microstructure leads to excellent electrochemical activity. As an electrode for Supercapatteries, beta-NiMoO4-NF showed a high specific capacity of 178.2 mA h g(-1) (916.4 F g(-1)) at 5 mA cm(-2) current density. Most importantly, the fabricated symmetric device exhibits a maximum specific energy of 35.8 W h kg(-1) with the power output of 981.56 W kg(-1) and excellent cyclic stability. In methanol electro-oxidation, the beta-NiMoO4-NF catalyst deliver the high current density of 41.8 mA cm(-2) and much lower onset potential of 0.29 V with admirable long term stability. Apart from the above electrochemical activity, the beta-NiMoO4-NF honeycomb microstructure demonstrates a promising non-noble electrocatalyst for oxygen evolution reaction (OER) and hydrogen evolution reaction (HER) and showed a considerable overpotential of 351 mV (OER) and 238 mV (HER). The attractive multifunctional electrochemical activity of beta-NiMoO4-NF could be originates from their unique honeycomb micro/nano structure which can acts as an "ion reservoir" and thus leads to superior energy storage and conversion processes. (C) 2020 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.