García-Sánchez A., Gomez-Mendoza M., BarawiI M., Villar-Garcia I., Liras M., Gándara F., de la Peña O’Shea V. A. ”Fundamental insights into photoelectrocatalytic hydrogen production with a hole-transport bismuth metal–organic framework” Journal of the American Chemical Society 2020, 142, 1, 318-326
Due to the current situation of growing greenhouse gas emission, it is crucial search for sustainable energy sources as alternative to fossil fuels. For that purpose, it is necessary to develop process that effectively exploit renewable natural resources, being the solar energy of the main ones. In this sense, MOF or Metal Organic Frameworks are emerging as promising materials due to its tailorable capacity to absorb light by the smart selection of its components.
The lasts advances in the Solar Fuels of Photoactivated Processes Group of IMDEA Energy was recently published in prestigious Journal of the American Chemical Society (JACS) entitled Fundamental Insights into Photoelectrocatalytic Hydrogen Production with a Hole-Transport Bismuth Metal–Organic Framework. We have designed and synthesized a new MOF, based on bismuth and an electron-rich linker with hole transport ability. This new structure denoted IEF-5 (IMDEA Energy Framework-5) was successfully applied in photoelectrochemical hydrogen production with the absence of co-catalyst. There is only one previous example employing a material with these characteristics. The optolectronic characteristic of this materials lead to obtain very promising H2 production even thought are tested laboratory scale results.
One to the most remarkable issues of this work is the deeply understanding of the mechanism pathways involved in H2 photo-production. Thus, several characterization techniques at different time scales were combined with theoretical calculations giving the elucidation of the involved charge transfer and to understand their role in the reaction mechanism (Figure 1) . It is expected that this progress will allow the design of new materials with improved H2 yield or to be applied to other light mediated processes.
Scheme of photo(electro)catalytic H2 production mechanism, where S0 (Fundamental state), S1 (Singlet excited state); T1 (Triplet excited state), A (Anion) and ISC (Intersystem crossing).