Research database

RECYCLE-CO2 focuses on the electrochemical reduction of CO2 (CO2RR) into valuable chemicals and fuels using innovative and selective electrocatalysts. CO2RR, although being very promising, confronts many challenges due to the low energy content in CO2, high reaction energy barriers, slow kinetics for CO2 electroreduction, and low selectivity toward a specific product. Therefore, the design and development of highly active and selective catalysts is crucial for practical application of electrocatalytic CO2RR. In this project, high-efficiency electrochemical CO2 conversion will be achieved by synthesizing a new generation of single atom catalysts (SACs) with engineered dual-coordination dispersed in carbon nanotubes. The state of the art of CO2RR catalysts based on SACs mainly consists of transition metal atoms (M) with porphyrin-like M-N4 moieties embedded in the support. In RECYCLE-CO2, we aim at achieving direct control of SACs’ activity and selectivity by modifying M first coordination shell. With this goal, we will substitute one or more N atoms in the M-N4 moiety with less electronegative elements, such as P and S. We expect that this will result in unique electronic properties (e.g. charge/spin states, electron density near Fermi level), distinct from those observed for the corresponding M-N4. Specifically, we aim at forming asymmetrical atomic interfaces with a tunable energy level of the metal d orbitals in order to facilitate the binding of CO2RR key intermediates on the active sites and lower their adsorption energy barriers. The control over the SAC structural and electronic properties will allow us guiding the reaction towards specific C1 products such as CO, HCOOH, CH4 and CH3OH. The goal of RECYCLE-CO2 is not only the preparation of SAC electrocatalysts, but is more ambitious: by combining theory and experimental approaches, we want to develop a reliable procedure to modify and control the electronic and structural properties of SACs, by engineering the SACs’ local environment, in order to boost the CO2RR reaction and tune the products selectivity. Materials innovation will be guaranteed by a collaborative network gathering theoretical and experimental know-how. Ab initio simulations will be combined with state-of-the art analysis of the catalyst during realistic operando conditions to identify the catalytically active sites and clarify reaction mechanism. This will provide a fundamental understanding of structure/composition-activity relationships and will allow tailoring SAC coordination shell to achieve improved selectivity. The research groups involved in RECYCLE-CO2 have complementary expertise which will guarantee successful achievements of the project objectives, in particular: (i) the group at UNIPD has unique know-how in the synthesis and operando characterization of innovative electrocatalysts; (ii) the group at Politecnico di Torino (POLITO) is expert in catalysts design by means of ab initio simulations.