Light-responsive MOF films offer scalable solution for carbon capture and storage

The study, conducted by an interdisciplinary team that included scientists from the research infrastructure consortium CERIC-ERIC, Elettra Sincrotrone Trieste, Graz University of Technology (TU Graz) and the Istituto Officina dei Materiali (IOM) of the National Research Council of Italy (IOM-CNR), has been recently published in Nature Communications. In their research, supported by CERIC-ERIC, scientists addressed a critical challenge in the field: adapting highly porous MOF materials into practical, durable, and responsive assemblies for the use in carbon capture and storage technologies, while maintaining their structural integrity and sorption capacity.

Carbon neutrality goals aim to mitigate human impact on climate change achieving a balance between carbon dioxide (CO₂) emissions and its adsorption or sequestration from the atmosphere. Within this context, MOFs, known for their exceptional porosity and tunable chemistry, are among the most promising candidates for future CO₂ mitigation strategies. However, their integration and use have been slowed down by difficulties in fabricating functional, stable forms—especially films or membranes—compatible with industrial systems. In this new study, researchers engineered flexible Zn-based MOF films grown as heteroepitaxial layered structures on substrates. These films incorporate functionalized organic linkers, including photo-switchable molecules like azobenzene, enabling reversible CO₂ capture triggered by light (both ultraviolet and visible).

“Our findings show that it is possible to design MOF films that not only operate at near-ambient conditions but can be controlled remotely using light—an appealing strategy for smart and energy-efficient carbon capture, that enables at the same time a non-invasive control over the system,” says principal investigator author Dr Sumea Klokic, who designed the experiment and performed the related measurements in the framework of CERIC-ERIC research and is now scientist at TU Graz. By tailoring linker chemistry, the team has unlocked enhanced flexibility and responsiveness in the Zn-MOF films enabling reversible CO₂ uptake and dynamic structural adaptation at near-ambient conditions. “Using a combination of cutting-edge analytical techniques available in CERIC-ERIC Partner Facilities  — including grazing incidence wide angle X-ray scattering (GIWAXS) and infrared spectromicroscopy — we have been able to deeply characterise the reversible, low-energy system we developed, observing molecular-scale interactions and quantifying CO₂ uptake in real time —especially under external stimuli such as light and temperature.” adds Dr Giovanni Birarda, researcher at the beamline SISSI-Bio of Elettra Sincrotrone Trieste. At the SISSI beamline, infrared spectromicroscopy allows researchers to investigate the spatial distribution and molecular dynamics of CO₂ within the MOF films with high chemical specificity and micrometric resolution.

Looking ahead, the researchers highlight the need for improved nanoscale imaging techniques – such as the ones that will be developed during the upcoming upgrade of Elettra Sincrotrone Trieste (Elettra 2.0), that will strive to provide complementary synchrotron methods to probe dynamic processes at even smaller length scales – to eventually map the CO₂ distribution within MOF films. Such insights could unlock further application of MOFs besides carbon storage, including gas separation devices, mixed matrix membranes, and environmental sensors.