High-porosity carbon molybdenum sulphide

Researchers from DTU Physics have publisheded a paper in the April issue of Chemical Communication describing a highly active and stable acid activated carbon fibre and amorphous MoSxcomposite hydrogen evolution catalyst. 

A high-porosity carbon molybdenum sulphide composite with enhanced electrochemical hydrogen evolution and stability

Anders B. Laursen, Peter C. K. Vesborg and Ib Chorkendorff  
Center for Individual Nanoparticle Functionality, Department of Physics, Fysikvej building 307, 2800 Kgs. Lyngby, Denmark 

Recently an electrodeposited form of molybdenum sulfide has been developed for use as an H2 evolution catalyst in the electrolysis field1.  However this material has always been tested on a planar surface.  Since the deposition, and hence activity, of this catalyst is dependent on surface area, it was theorized that an increase in surface area would allow for an increase in activity.  In this work we investigated using a porous carbon support in the attempt to find a high surface area to deposit the catalyst.  The green curve in Figure 1 shows that the catalytic efficiency towards H2 evolution is greatly enhanced by using a porous conductive support compared to a planar surface (blue line).  This figure also shows that increasing the electrodeposition procedure from 19 cycles to 50 cycles can make a notable improvement on performance.  Furthermore, the hydrophilicity of the carbon paper can be enhanced/activated by an acid treatment.  Using this activated porous carbon support the H2 evolution efficiency can be enhanced even further (red line). 

A high-porosity carbon molybdenum sulphide composite

Figure 1: Cyclic voltammograms of electrodeposited MoSx H2 evolution catalysts in 1M HClO4 in H2 atmosphere using a Hg/HgSO4 reference and a Pt counter.  The blue curves correspond to a fluorine doped tin oxide electrode support, the green curves use a carbon paper support, and the red curves use an activated carbon paper as a support.  Both a 19 cycle and a 50 cycle catalyst deposition was done and tested with each support.

  

1. Merki, D.; Fierro, S.; Vrubel, H.; Hu, X., Amorphous molybdenum sulfide films as catalysts for electrochemical hydrogen production in water. Chemical Science 2011, 2 (7), 1262-1267.

Contact

Ib Chorkendorff
Professor
DTU Physics
+45 45 25 31 70