Metal-Organic Framework Based Photoelectrochemical Cells

Photoelectrochemical cells (PECs), which directly convert sunlight into chemical fuels, are considered to be one of the most promising and economically feasible future technologies for producing alternative energy sources.¹

Metal−organic frameworks (MOFs) are a high surface area sub-class of coordination polymers, consisting of organic linkers bounded to metal-based nodes. MOFs display exceptional properties such as large surface area, permanent porosity and chemically tunable structures. By a clever selection of the right building blocks, it is possible to tune and modify the MOF chemical and photo physical properties^2-4. In recent years, MOFs containing light absorbing moieties/catalytic units have been successfully used in photocatalytic solar fuels reactions. Currently however, the field of MOF-based PECs is only in its infancy.

Herein we introduce two different approaches for the utilization of MOFs in PECs. First, high areal concentrations of molecular chromophores are assembled within a MOF film mounted on transparent conductive substrates, producing a semiconductor-less version of dye sensitized PEC. Detailed study on the effect of chromophore surface-loading and electrolyte composition will be presented.

In addition, we show that a MOF-derived metal-oxide layer can act as an efficient oxygen evolution co-catalyst in a BiVO₄ based photoelectrochemical water splitting cell. In depth chemical and photo-physical characterization of the system will be provided.

References:

1.Michael F. Lichterman Matthew R. Shaner, Sheila G. Handler, Bruce S. Brunschwig, Harry B. Gray, Nathan S. Lewis, and Joshua M. Spurgeon, J. Phys. Chem. Lett., 2013, 4 (23), 4188–4191

2.Rajnish Kaur,Ki-Hyun Kim,A. K. Paul and Akash Deep, J. Mater. Chem. A, 2016, 4, 3991-4002

3.Aneek Kuila, Nur A. Surib Nirmalendu S. Mishra, Ahmad Nawaz, Kah H. Leong, Lan C. Sim, Pichiah Saravanan and Shaliza Ibrahim, ChemistrySelect 2017, 2, 6163 –6177

4.Idan Hod, Matthew D. Sampson, Pravas Deria, Clifford P. Kubiak, Omar K. Farha, and Joseph T. Hupp ,ACS Catal., 2015, 5 (11), 6302–6309