Effect of V2+ and V4+-Doping on the Performance of Mos2 Catalysts for H2 Generation in Microbial Electrolytic Cells

Abstract

In this study, a series of vanadium-doped MoS2 (V-MoS2) powders synthesized via a hydrothermal method were coated on nickel foam (NF) as the cathode in microbial electrolysis cells (MECs). It is verified that the doped V was incorporated into the MoS2 lattice with the state of V2+ and V4+, and especially V2+ bonded with edge the sulfur atom while V4+ replaced the Mo4+ and embedded in the crystal lattice of Mo-S. Meanwhile, the doping ratio of V2+/V4+ decreased with the increase in the doping content of V, revealing that the V4+ is more beneficial for the efficiency of V-doping. Electrochemical testing demonstrated that the optimal doping amount of 10% V significantly enhanced the electrical conductivity and electrochemical activity of MoS2 by the activating of the inert basal plane. In the MEC system, the 10% V-MoS2 based electrode achieved a peak current density of 84.3 mA cm−2 with a hydrogen production rate of 289 L H2 L−1 cycle−1, a coulombic efficiency of 80.61% and a cathodic hydrogen conversion efficiency of 44.84%, which is much better than many conventional MEC catalysts, demonstrating a great potential for green hydrogen production.

Keywords: Microbial electrolysis cells, Cathode catalyst, V-MoS2, Electrochemical catalytic performance, hydrogen production