The Research On Hydrogen Production Performance Of MECs With NANO-MoS₂ Used As Cathode Catalyst

Microbial electrolysis cell（MEC） is a good way to deal with effluent from dark fermentation, leading to a more efficient utilization of biomass resources. However, this technology has to use noble- metal Pt as the cathode catalys that leads to the increase of production cost. O n the other hand, it is difficult for hydrogen generation through MEC from butyric acid because bacteria on anode can hardly consume butyric acid directly.This study firstly examined whether nano-MoS₂ could be alternative of Pt as the cathode catalyst in the MECs to generate hydrogen, it turned out that when loading ratio was 20%-wt, the overpotential of cathode was close to that of Pt/C cathode. Then we used 1 g/L sodium acetate as substrate in MEC to produce hydrogen process, at the applied voltage of 0.9 V, we got largest hydrogen yield 819.84 mL/g-NaAc and highest hydrogen production rate（HPR）3.027 m3/m3/d, the hydrogen generation performance and energy recovery and the related parameters paralleled performance of Pt/C MEC.Then the experiment was to examine the performance of hydrogen generation from butyric acid. 1 g/L butyric acid was used as substrate in the MFC to cultivate exoelectrogens onto anode. The result showed that MEC would make better use of butyric acid to produce hydrogen when butyric acid was used to gather exoelectrogens. For Hydrogen generation, when butyric acid was used as substrate in the MEC, we got hydrogen yield 791.38 mL/g NaBu and HPR 1.892 m3/m3/d at applied voltage of 0.8 V; when mixed VFAs was used as substrate, we got largest butyrate removal 48%; And when dark fermentation effluent was used as substrate, we got HPR 5.22± 0.09 m3/m3/d at applied voltage of 0.8 V, and butyrate removal 41.1%, the largest COD removal 69% at applied voltage of 0.5 V.Besides,we studied the performance of MEC when Ce（Ⅳ） and Fe（OH）₃ was used as cocatalyst. Result showed that Fe（OH）₃ nearby the anode could help cultivating more efficient anode;and when concentration of Ce（Ⅳ） in MEC was less than 0.010 mg/L, bacteria on anode could make better use of butyric acid to generate hydrogen gas.