Periodic Reporting for period 1 - SAC_2.0 (Single-Atom Catalysts for a New Generation of Chemical Processes: from Fundamental Understanding to Interface Engineering)
Berichtszeitraum: 2023-05-01 bis 2025-10-31
Single-atom catalysts (SACs) are an emerging class of materials that push the boundaries of catalysis by maximizing the efficiency of metal usage. Unlike traditional catalysts that rely on clusters or nanoparticles, SACs feature individual metal atoms anchored to a support, making every atom accessible for reaction. This unique architecture can lead to unparalleled catalytic activity and selectivity, opening new avenues for cleaner and more efficient chemical processes. However, harnessing the full potential of SACs remains a formidable challenge. It requires precise control over the placement and environment of each atom, advanced techniques to visualize and characterize their structure at the atomic scale, and innovative strategies to implement them in realistic, scalable systems. Funded through an ERC Starting Grant, the SAC_2.0 project was established to address these interconnected challenges through a multifaceted approach that combines atomic-level catalyst design, advanced manufacturing techniques, and cross-disciplinary collaboration spanning chemistry, materials science, and engineering.
Central to the project is the advancement of carbon nitride (CNx)-based SACs, where isolated metal atoms are anchored within a structured, tunable support. SAC_2.0 aimed to gain deep insights into the structure and reactivity of these catalysts, to develop scalable and reproducible fabrication methods, and to demonstrate their utility in continuous-flow reactor systems for sustainable chemical transformations. In doing so, the project sought to pave the way for a new generation of environmentally friendly catalytic technologies. The expected outcomes include major progress in sustainable catalysis, improved resource efficiency, and the creation of atomically designed reactor platforms tailored for scalable photochemical processes. In sum, SAC_2.0 intends to shape a future where chemical production is more selective, efficient, and environmentally responsible.
Central to the project is the advancement of carbon nitride (CNx)-based SACs, where isolated metal atoms are anchored within a structured, tunable support. SAC_2.0 aimed to gain deep insights into the structure and reactivity of these catalysts, to develop scalable and reproducible fabrication methods, and to demonstrate their utility in continuous-flow reactor systems for sustainable chemical transformations. In doing so, the project sought to pave the way for a new generation of environmentally friendly catalytic technologies. The expected outcomes include major progress in sustainable catalysis, improved resource efficiency, and the creation of atomically designed reactor platforms tailored for scalable photochemical processes. In sum, SAC_2.0 intends to shape a future where chemical production is more selective, efficient, and environmentally responsible.
Over two years of intensive research and development, SAC_2.0 achieved a series of scientific and technological milestones that significantly advanced the field of atomically precise catalysis. One of the most notable outcomes was the proposal and validation of a new structural model for CNx-supported SACs. Focusing on nickel-based systems, the project identified square-planar Ni–N4 configurations embedded in melem-derived carbon nitride filaments as the catalytically active sites.
To support this finding, the team employed a robust suite of characterization tools, including X-ray absorption spectroscopy, density functional theory (DFT) simulations, and electron microscopy combined with spectroscopy. These methods not only confirmed the structure at the atomic level but also enabled the distinction between true active sites and impurities, an ongoing challenge in the field.
Building on this structural understanding, SAC_2.0 developed precise synthetic methodologies based on hard-template polymerization. These allowed for the scalable production of monoatomic catalysts with tightly controlled metal loading and dispersion. The materials, which included Ni, Ag, Zn, Cu, and Pd-based SACs, showed high surface areas and complete atomic dispersion, meeting key benchmarks for reproducibility and performance.
The project also pioneered the integration of SACs into 3D-printed reactor systems through VAT photopolymerization. These custom-designed monolithic reactors featured tailored geometries that improved light utilization and mass transport. When tested under continuous-flow conditions for photocatalytic oxidation reactions, the devices demonstrated high turnover numbers and excellent recyclability. For example, Ag1@CNx achieved a turnover number (TON) of 1098 in benzyl alcohol oxidation.
Furthermore, life cycle assessments (LCA) showed that these SAC-based processes offer clear environmental advantages over traditional catalytic systems, including reduced CO2 emissions and reduced energy and resource consumption. Together, these achievements have positioned SAC_2.0 as a model for atomically precise catalysis research in Europe.
To support this finding, the team employed a robust suite of characterization tools, including X-ray absorption spectroscopy, density functional theory (DFT) simulations, and electron microscopy combined with spectroscopy. These methods not only confirmed the structure at the atomic level but also enabled the distinction between true active sites and impurities, an ongoing challenge in the field.
Building on this structural understanding, SAC_2.0 developed precise synthetic methodologies based on hard-template polymerization. These allowed for the scalable production of monoatomic catalysts with tightly controlled metal loading and dispersion. The materials, which included Ni, Ag, Zn, Cu, and Pd-based SACs, showed high surface areas and complete atomic dispersion, meeting key benchmarks for reproducibility and performance.
The project also pioneered the integration of SACs into 3D-printed reactor systems through VAT photopolymerization. These custom-designed monolithic reactors featured tailored geometries that improved light utilization and mass transport. When tested under continuous-flow conditions for photocatalytic oxidation reactions, the devices demonstrated high turnover numbers and excellent recyclability. For example, Ag1@CNx achieved a turnover number (TON) of 1098 in benzyl alcohol oxidation.
Furthermore, life cycle assessments (LCA) showed that these SAC-based processes offer clear environmental advantages over traditional catalytic systems, including reduced CO2 emissions and reduced energy and resource consumption. Together, these achievements have positioned SAC_2.0 as a model for atomically precise catalysis research in Europe.
The innovations delivered by SAC_2.0 have redefined the current state of the art in several key domains of single-atom catalysis. In terms of structural understanding, the project resolved longstanding ambiguities concerning metal coordination in CNx materials, providing unambiguous evidence for N4 coordination environments through a combination of experimental and theoretical techniques.
On the characterization front, the integration of spectroscopy with advanced electron microscopy enabled unprecedented accuracy in identifying genuine single-atom sites, eliminating artefacts that previously hindered progress. These diagnostic tools have since been adopted by other research groups and projects, demonstrating their broad utility.
From a synthetic perspective, SAC_2.0 introduced versatile and scalable methodologies for producing ultra-dispersed SACs across a range of metals and supports. This flexibility enhances the applicability of SACs across diverse chemical reactions and industrial sectors. Equally transformative was the application of digital manufacturing to catalysis. By embedding SACs within 3D-printed reactor architectures, the project demonstrated how additive manufacturing can be leveraged to create advanced catalytic systems with improved light distribution and fluid dynamics. These reactors are particularly suited for photon-limited conditions, extending the operational range of SACs.
The project also validated the high performance of these systems in a variety of applications of key relevance for the manufacture of fine chemicals, with experimental results supported by operando spectroscopy and simulations that revealed the critical role of metal–support interactions in exciton dynamics and charge separation. Finally, SAC_2.0 confirmed the sustainability benefits of these technologies through comprehensive life cycle and techno-economic assessments.
Through its achievements, SAC_2.0 has established the Politecnico di Milano as a leading European hub for single-atom catalysis, while positioning its PI (Prof. Dr. Gianvito Vilé) as a prominent voice in the field. The PI has received major recognitions, including the 2025 EFCATS Young Researcher Award. He has been elected to the Young Academy of Europe and the Italian National Academy of Technology and Engineering, and has received the Alfredo Di Braccio Award from the Italian National Academy of Sciences (Accademia Nazionale dei Lincei). In addition, he secured an ERC Proof of Concept grant to explore the commercial viability of SAC_2.0's technologies, demonstrating the project's potential for real-world application. The project's outcomes have influenced a wide network of academic and industrial collaborations, reflected in highly-cited publications, invited lectures, and the transfer of methodologies to other European initiatives. In summary, SAC_2.0 has not only advanced the frontiers of catalysis research but has laid a robust foundation for future developments in sustainable chemical manufacturing. The future of catalysis is atomically precise, and SAC_2.0 is bringing that future closer to reality.
On the characterization front, the integration of spectroscopy with advanced electron microscopy enabled unprecedented accuracy in identifying genuine single-atom sites, eliminating artefacts that previously hindered progress. These diagnostic tools have since been adopted by other research groups and projects, demonstrating their broad utility.
From a synthetic perspective, SAC_2.0 introduced versatile and scalable methodologies for producing ultra-dispersed SACs across a range of metals and supports. This flexibility enhances the applicability of SACs across diverse chemical reactions and industrial sectors. Equally transformative was the application of digital manufacturing to catalysis. By embedding SACs within 3D-printed reactor architectures, the project demonstrated how additive manufacturing can be leveraged to create advanced catalytic systems with improved light distribution and fluid dynamics. These reactors are particularly suited for photon-limited conditions, extending the operational range of SACs.
The project also validated the high performance of these systems in a variety of applications of key relevance for the manufacture of fine chemicals, with experimental results supported by operando spectroscopy and simulations that revealed the critical role of metal–support interactions in exciton dynamics and charge separation. Finally, SAC_2.0 confirmed the sustainability benefits of these technologies through comprehensive life cycle and techno-economic assessments.
Through its achievements, SAC_2.0 has established the Politecnico di Milano as a leading European hub for single-atom catalysis, while positioning its PI (Prof. Dr. Gianvito Vilé) as a prominent voice in the field. The PI has received major recognitions, including the 2025 EFCATS Young Researcher Award. He has been elected to the Young Academy of Europe and the Italian National Academy of Technology and Engineering, and has received the Alfredo Di Braccio Award from the Italian National Academy of Sciences (Accademia Nazionale dei Lincei). In addition, he secured an ERC Proof of Concept grant to explore the commercial viability of SAC_2.0's technologies, demonstrating the project's potential for real-world application. The project's outcomes have influenced a wide network of academic and industrial collaborations, reflected in highly-cited publications, invited lectures, and the transfer of methodologies to other European initiatives. In summary, SAC_2.0 has not only advanced the frontiers of catalysis research but has laid a robust foundation for future developments in sustainable chemical manufacturing. The future of catalysis is atomically precise, and SAC_2.0 is bringing that future closer to reality.