Effect of V2+ and V4+-doping on the performance of MoS2 catalysts for H2 generation in microbial electrolytic cells

In this study, a series of vanadium-doped MoS 2 (V-MoS 2 ) 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 MoS 2 lattice with the state of V 2+ and V 4+ , and especially V 2+ bonded with edge the sulfur atom while V 4+ replaced the Mo 4+ and embedded in the crystal lattice of Mo S. Meanwhile, the doping ratio of V 2+ /V 4+ decreased with the increase in the doping content of V, revealing that the V 4+ is more beneficial for the efficiency of V-doping. Electrochemical testing demonstrated that the optimal doping amount of 10 % V significantly enhanced the electrochemical activity of MoS 2 by the activating of the inert basal plane. In the MEC system, the 10 % V-MoS 2 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.