Increasing the global energy demand as well as the carbon dioxide (CO₂) level in the atmosphere caused by burning fossil fuel as the main source of energy motivate the development of green energy technologies. However, the real activity improvement for these technologies is mainly impeded by intermittent nature of renewable energy technologies. One smart approach to overcome this issue is to store energy into the chemical bonds^1–6 using inexpensive and efficient energy conversion and storage technologies. In these systems, energy can be converted or stored into chemical bonds as a form of fuels or electricity using renewable energy sources, e.g., solar and wind energy^7–9. Despite recent progress, the development of these systems is advanced far more slowly due to the expensive and less efficient materials employed in these technologies.

Here, I will present my aim to design, synthesis, and characterization of inexpensive earth-abundant transition metal dichalcogenide class of materials suitable for energy conversion and storage systems. I have tested the performance of this class of catalysts for the carbon dioxide (CO₂) reduction reaction, oxygen reduction, oxygen evolution reactions. The results indicate (i) 100 times higher turn over frequency- per atom activity- far exceeding the performance of state-of-the-art catalysts for CO₂ reduction reaction, and (ii) a highly efficient bi-functional catalyst for oxygen reduction and evolution reactions in the aprotic media compared to conventional noble metal catalysts used for the same application (e.g., Platinum and Gold). I also tested the performance of molybdenum disulfide nanoflakes (MoS₂ NFs) -a versatile member of TMDCs- in lithium-air batteries known as a promising alternative to the conventional lithium-ion batteries. The results indicate that MoS₂ NFs in the ionic liquid EMIM-BF₄ electrolyte performs remarkably well in the actual air environment with a small discharge/charge potential gap as well as good stability and cyclability up to 550 cycles without any evidence of failure. I will discuss these and other results including the potential of our recent discovery to open a new route towards energy efficient, highly active and cost-effective energy storage and conversion systems to replace fossil fuels.

References:

1. Asadi, M. et al. Nanostructured transition metal dichalcogenide electrocatalysts for CO₂ reduction in ionic liquid. Science 353, 467–470 (2016).
2. Asadi, M. et al. Robust carbon dioxide reduction on molybdenum disulfide edges. Nat. Commun. 5, 4470 (2014).
3. Behranginia, A. et al. Highly Efficient Hydrogen Evolution Reaction Using Crystalline Layered Three-Dimensional Molybdenum Disulfides Grown on Graphene Film. Chem. Mater. 28, 549–555 (2016).
4. Asadi, M. et al. Cathode Based on Molybdenum Disulfide Nanoflakes for Lithium-Oxygen Batteries. ACS Nano 10, 2167–2175 (2016).
5. Lu, J. et al. A lithium-oxygen battery based on lithium superoxide. Nature 529, 377–382 (2016).
6. Abbasi, P. et al. Tailoring the Edge Structure of Molybdenum Disulfide toward Electrocatalytic Reduction of Carbon Dioxide. ACS Nano 11, 453–460 (2017).
7. Seh, Z. W. et al. Combining theory and experiment in electrocatalysis: Insights into materials design. Science (80-. ). 355, eaad4998 (2017).
8. Montoya, J. H. et al. Materials for solar fuels and chemicals. Nat. Mater. 16, 70–81 (2016).
9. Chu, S., Cui, Y. & Liu, N. The path towards sustainable energy. Nat. Mater. 16, 16–22 (2016).