Preparation and Electrochemical Evaluation of MoS2/graphene as a Catalyst for Hydrogen Evolution in Microbial Electrolysis Cell

A series of MoS2/graphene (MoS2/Gr) composites was prepared via simple hydrothermal method, and loaded on the carbon. based electrode. The as-prepared samples were characterized by scanning electron microscopy, transmission electron microscopy, linear sweep voltammetry, and so on. The hydrogen evolution performance of MoS2/Gr electrode as the cathode of microbial electrolysis cell (MEC) was studied. The results showed that the MoS2/Gr materials held a three-dimensional layered structure, and the molybdenum sulfide loaded on graphene was amorphous MoS2. The composite prepared from 50% (mass fraction) (NH4)(2) MoS4 and 50%(mass fraction) graphene oxide with a surface density of 1.5 mg/cm(2) exhibited the best catalytic activity for hydrogen evolution reaction. In the MEC tests, the MoS2/Gr cathode was comparable with the Pt/C cathode in term of energy efficiency. The average current density of hydrogen production, hydrogen production rate, coulomb efficiency, hydrogen recovery and cathodic hydrogen recovery obtained with MoS2/Gr cathode MEC were (9.96 +/- 0.65) A/m(2), (0.424 +/- 0.041) m(3) H-2 /(m(3) . d), (89.11 +/- 5.87)%, (70.47 +/- 6.78)% and (78.86 +/- 2.49)%, respectively, higher than those obtained with the Pt/C cathode MEC. In addition, the MoS2/Gr cathode exhibited good stability, and it was inexpensive. These advantages make it suitable for practical application.