Periodic Reporting for period 1 - reaCtor (Fibre-based plasmonic micro reactor for flow chemistry)
Période du rapport: 2023-04-01 au 2024-03-31
Major challenges of the European society such as the climate crisis, insufficient environmental protection, pharmaceutical shortages, and military risks require solutions that substitute fossil fuels by sustainable energy sources and significantly reduce energy consumption in basically all industries. Following the green deal of the EU commission, the European continent shall become the first climate-neutral continent by 2050. Particularly, the chemical industry is a major contributor to CO2 emissions as it accounts for about 12 % of industry’s total energy use worldwide and is responsible for 5% of the greenhouse gas emissions in the EU. As a consequence, disruptive new technologies must be developed to reduce greenhouse gas emissions.
It is widely agreed that photochemistry in flow reactors is an eco-friendly and safe technology for the synthesis of organic compounds and further applications such as water treatment. Compared to batch reactors, flow photochemistry benefits significantly from continuous flow due to improved reaction selectivity, irradiation conditions, mass and heat exchange, and operation safety. However, despite the overwhelming advantages of microreactor flow photochemistry, the technique has not been widely adopted by the chemical industry, so far. A major bottleneck is the missing light management inside the microflow reactors, which significantly hinders its upscaling and large-scale application in industry. This is exactly where the key to the technological and economic breakthrough lies, and this is where reaCtor comes into play by offering an innovative solution. By integrating a chemical reactor inside a specialty optical glass fibre, where the reaction is enabled through light-driven plasmonic nanoparticles, our approach allows for unprecedented levels of light management and industry demanded scale-up.
To reach this ambitious goal, the interdisciplinary reaCtor consortium works on several major objectives. A novel microreactor fibre for high efficiency interaction with the reaction volume is designed, fabricated, and validated. In addition, a novel monolithic fibre component for high-efficiency light in-coupling is under development. Furthermore, a versatile laser-based micro-machining process for micro-fluidic interfacing of the microreactor fibre is currently tested. For enhanced reactant excitation and flow photochemical reaction yield, plasmonic nanoparticles are designed to match the reaction conditions and will be distributed and attached in the microreactor fibre. The final outcome of reaCtor will be a demonstrator of the proposed microreactor, which will be validated and benchmarked with respect to a number of photochemical reactions. The technical work is accompanied by a strong dissemination and communication strategy to engage all relevant stakeholders.
It is widely agreed that photochemistry in flow reactors is an eco-friendly and safe technology for the synthesis of organic compounds and further applications such as water treatment. Compared to batch reactors, flow photochemistry benefits significantly from continuous flow due to improved reaction selectivity, irradiation conditions, mass and heat exchange, and operation safety. However, despite the overwhelming advantages of microreactor flow photochemistry, the technique has not been widely adopted by the chemical industry, so far. A major bottleneck is the missing light management inside the microflow reactors, which significantly hinders its upscaling and large-scale application in industry. This is exactly where the key to the technological and economic breakthrough lies, and this is where reaCtor comes into play by offering an innovative solution. By integrating a chemical reactor inside a specialty optical glass fibre, where the reaction is enabled through light-driven plasmonic nanoparticles, our approach allows for unprecedented levels of light management and industry demanded scale-up.
To reach this ambitious goal, the interdisciplinary reaCtor consortium works on several major objectives. A novel microreactor fibre for high efficiency interaction with the reaction volume is designed, fabricated, and validated. In addition, a novel monolithic fibre component for high-efficiency light in-coupling is under development. Furthermore, a versatile laser-based micro-machining process for micro-fluidic interfacing of the microreactor fibre is currently tested. For enhanced reactant excitation and flow photochemical reaction yield, plasmonic nanoparticles are designed to match the reaction conditions and will be distributed and attached in the microreactor fibre. The final outcome of reaCtor will be a demonstrator of the proposed microreactor, which will be validated and benchmarked with respect to a number of photochemical reactions. The technical work is accompanied by a strong dissemination and communication strategy to engage all relevant stakeholders.
Within the first year, the reaCtor consortium has made significant progress. Based on consortium-wide theoretical and numerical modelling efforts, a tentative design for the (sub)components of the microreactor was compiled. Particularly, an initial design for the optical fibre was found, considering the relevant effects and boundary conditions from all involved disciplines. It covers important parameters such as the inner fibre diameter, the operational wavelength, and a typical length. Based on the initial design, several so-called fibre preforms were manufactured via modified chemical vapour deposition and successfully validated. This demonstrates the general feasibility of one of the key ingredients to reaCtors’ technological approach. In preliminary experiments, the first preforms were successfully drawn into fibres and recent activities focused on step-wise iterative optimization of the preform and fibre fabrication process. In parallel, capillary fibres were used to establish an ultrafast femtosecond (fs) laser-based three-dimensional lithographic process to provide the fibres with micro-sized holes (in- and outlets), which will later enable a monolithic interfacing to standard microfluidic equipment and a constant flow through the reactor. The successful demonstration of the fs-based processing of the micro-sized holes corresponds to the first milestone of reaCtor. Besides the work on the fibre and its microfluidic functionalization, the consortium also made significant progress related to the plasmonic functionalization and the integration of the functionalized fibre in a photochemical flow reactor. For example, a protocol was established to functionalize fibre-mimicked surfaces with plasmonic nanoparticles. Furthermore, the consortium decided on a first benchmark reaction to test the functionality of the reactor, namely a well understood acceptor-photosensitizer with a relevant but uncomplicated reaction: methylene-blue as an intermediate for singlet oxygen production. Ultimately, we want to extend the flow chemistry to the very relevant imidazolium CO2 reduction driven by light through the generation of plasmonic hot electrons.
In parallel to the technical work, the reaCtor consortium laid a strong foundation for successful collaborative work, for example by setting up a joint cloud service for data exchange or an internal wiki for comprehensive access to joint presentation layouts etc. Regular meetings and exchange of staff is another key ingredient for the successful collaboration. Besides, a dedicated homepage and social media accounts were installed and will support the successful dissemination of the results.
In parallel to the technical work, the reaCtor consortium laid a strong foundation for successful collaborative work, for example by setting up a joint cloud service for data exchange or an internal wiki for comprehensive access to joint presentation layouts etc. Regular meetings and exchange of staff is another key ingredient for the successful collaboration. Besides, a dedicated homepage and social media accounts were installed and will support the successful dissemination of the results.
In particular, the initiative work and results on the novel optical fibre go well beyond the state of the art since such a microreactor fibre has never been realized before. Furthermore, the successful fs-laser based micromachining of micro-fluidic in-/outlet channels in the fibre has been demonstrated by the reaCtor consortium for the first time. Building on these promising first results, the next important scientific and technological steps will be the quantification of the plasmonic functionalization inside the fibre and microfluidic connection of the microreactor fibre as well as their integration into a monolithic optical and microfluidic setup. Corresponding work will involve the development of the all-fibre light in-coupling as well as the above-mentioned chemical reactions in the microreactor fibre. For the all-fibre in-coupling, the consortium developed a novel approach and is currently securing corresponding intellectual property rights. The consortium also agreed to compile its theoretical and numerical modelling results into a first scientific publication that will be published as open access so that the key findings and design guidelines will be made available to the public.