Electrochemical tests of the separate ingredients showed that molybdenum carbide is effective for converting H2O to H2, but not stable in acidic solution, while molybdenum nitride is corrosion-resistant but not efficient for hydrogen production. A nanostructured hybrid of these two materials, however, remained active and stable even after 500 hours of testing in a highly acidic environment.
"We attribute the high activity of the molybdenum-soy catalyst (MoSoy) to the synergistic effect between the molybdenum-carbide phase and the molybdenum-nitride phase in the composite material," Chen said.
Structural and chemical studies of the new catalyst conducted at Brookhaven's National Synchrotron Light Source (NSLS) and the Center for Functional Nanomaterials (CFN) are also reported in the paper, and provide further details underlying the high performance of this new catalyst.
"The presence of nitrogen and carbon atoms in the vicinity of the catalytic molybdenum center facilitates the production of hydrogen from water," Muckerman said.
The scientists also tested the MoSoy catalyst anchored on sheets of graphenean approach that has proven effective for enhancing catalyst performance in electrochemical devices such as batteries, supercapacitors, fuel cells, and water electrolyzers. Using a high-resolution transmission microscope in Brookhven's Condensed Matter Physics and Materials Science Department, the scientists were able to observe the anchored MoSoy nanocrystals on 2D graphene sheets.
The graphene-anchored MoSoy catalyst surpassed the performance of pure platinum metal. Though not quite as active as commercially available platinum catalysts, the high performance of graphene-anchored MoSoy was extremely encouraging to the scientific team.
"The direct growth of anchored MoSoy nanocrystals on graphene sheets may enhance the
|Contact: Karen McNulty Walsh|
DOE/Brookhaven National Laboratory