(764j) Advanced Catalyst for Energy Conversion and Storage Systems

Energy conversion and storage systems have received much more attentions as fossil fuel alternatives due to their great potential to store energy into the chemical bonds^1–5. 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^6–8. However, the performance of these systems are hindered due to the high cost and relatively poor performance i.e. low reaction rates and high overpotentials of state-of-the-art catalysts (e.g., noble metals)^9–11. Although many physical and chemical approaches have been employed to enhance the existing materials catalytic performance, it appears to be a fundamental limit, connected to the electronic structure of these catalysts.

Here, I will present my recent effort to design, synthesis and characterization of transition metal dichalcogenides (TMDCs) class of catalysts with unique electronic properties suitable for energy conversion and storage systems. We have tested the performance of this class of catalysts for the carbon dioxide (CO₂) reduction reaction, oxygen reduction reaction and oxygen evolution reactions. Our results include 100 times higher catalytic activity for the CO₂ reduction reaction, exceeding the performance of state-of-the-art catalysts and highly efficient bi-functional catalysts for oxygen reduction and evolution reactions compared to expensive noble metal catalysts such as platinum and gold in the aprotic media. We also tested the performance of molybdenum disulfide nanoflakes (MoS₂ NFs) -a member of TMDCs- in lithium-oxygen batteries known as potential alternative of lithium-ion batteries. 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. Robust carbon dioxide reduction on molybdenum disulphide edges. Nat. Commun. 5, 4470 (2014).

2. 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).

3. Asadi, M. et al. Cathode Based on Molybdenum Disulfide Nanoflakes for Lithium-Oxygen Batteries. ACS Nano 10, 2167–2175 (2016).

4. Lu, J. et al. A lithium–oxygen battery based on lithium superoxide. Nature 529, 377–382 (2016).

5. Abbasi, P. et al. Tailoring the Edge Structure of Molybdenum Disulfide towards Electrocatalytic Reduction of Carbon Dioxide. ACS Nano acsnano.6b06392 (2016). doi:10.1021/acsnano.6b06392

6. May, M. M., Lewerenz, H.-J., Lackner, D., Dimroth, F. & Hannappel, T. Efficient direct solar-to-hydrogen conversion by in situ interface transformation of a tandem structure. Nat. Commun. 6, 8286 (2015).

7. Jingshan, L. et al. Water photolysis at 12.3% efficiency via perovskite photovoltaics and Earth-abundant catalysts. Science (80-. ). 345, 1593–1596 (2014).

8. Chang, X., Wang, T. & Gong, J. CO2 Photo-reduction: Insights into CO2 Activation and Reaction on Surfaces of Photocatalysts. Energy Environ. Sci. (2016). doi:10.1039/C6EE00383D

9. Chen, Y., Li, C. W. & Kanan, M. W. Aqueous CO 2 Reduction at Very Low Overpotential on Oxide-Derived Au Nanoparticles. J. Am. Chem. Soc. 134, 19969–19972 (2012).

10. Li, C. W. & Kanan, M. W. CO 2 Reduction at Low Overpotential on Cu Electrodes Resulting from the Reduction of Thick Cu 2 O Films. J. Am. Chem. Soc. 134, 7231–7234 (2012).

11. DiMeglio, J. L. & Rosenthal, J. Selective Conversion of CO 2 to CO with High Efficiency Using an Inexpensive Bismuth-Based Electrocatalyst. J. Am. Chem. Soc. 135, 8798–8801 (2013).