Microwave synthesis technique could pave way for lower cost hydrogen
Scientists at the Center for Nanoscale Materials have synthesized what could be a low-cost earth-abundant catalyst for making hydrogen, according to the Department of Energy Office of Science. The scientists employed a microwave synthesis technique that helps create a nanostructured molybdenum disulfide material, which has the potential to be an affordable alternative to the platinum catalysts currently used. The performance exceeds that of MoS2 materials made via other synthetic methods.
As reported by the Office of Science via Newswise, the goal of the scientists is to use energy from intermittent renewable sources to create hydrogen and then use fuel cells to release the energy on demand.
Under investigation is a layered MoS2 material. Prior research has shown that catalytic activity is primarily in sites on the edges of sheets of the material. The scientists have demonstrated that the microwave synthesis technique can help create nanostructured MoS2 catalysts with an improved ability to produce hydrogen.
They report that theoretical calculations show the microwave-assisted strategy works partially through a change in the interaction between the hydrogen and MoS2 edge sites when the space between individual layers of MoS2 nanosheets is increased. The increase in space also exposes a larger fraction of reactive sites along the edges of these surfaces where hydrogen can be produced.
They further report that the performance of the microwave-created MoS2 nanostructured material is among the best of current MoS2 catalysts, requiring only 0.1 V of extra voltage, compared with platinum, for the beginning of hydrogen evolution. Furthermore, they add, the microwave method is more energy-efficient than thermal synthesis, and it offers the possibility of designing tailored MoS2 catalysts through precise control of the interlayer distance.
Their work is described in Nature Communications.*
*Gao, M. R., Chan, M. K. Y., and Sun, Y., “Edge-terminated Molybdenum Disulfide with a 9.4Å- interlayer Spacing for Electrochemical Hydrogen Production.” Nature Communications 6, 7493, 2015.
