Formation of Single Metal Atom Coordinated with Four Nitrogen Atoms in Carbon Nano-Onions for Efficient and Selective CO2 Conversion into Fuels

This proposal aims to achieve an efficient, selective, and robust electrochemical conversion of CO2 into value added chemicals and fuels. The efficient electorchemical CO2 reduction (CO2RR) will provide an essential and sustainable tool for the successful execution of the Mars mission by providing in-situ resource utilization (ISRU) technologies since the atmosphere of Mars is mostly CO2 (96%). If successful, this project will achieve several innovations in science and technologies. First, economic and tailorable use of precious and non-precious metals will be achieved by employing single metal based catalysts. Second, well-defined metal-ligand complexes formed by coordinating single metal atom with 4 nitrgen atoms will resolve a long-standing issue of metal agglomeration during the extended operation of catalysts. Third, the high curvature of CNO support will further enhance CO2RR activity of metal-N4 active sites. Various synthetic approaches including top-down methods and bottom-up methods will be tested to develop the M-N4 sites and incorporate them into CNOs. One way is a step-wise approach by (i) incorporating nitrogen atoms into CNOs by chemical oxidation and reaction with nitrogen containing precursors, and then (ii) adding metallic ions to form linkages with nitrogen atoms (see Figure 1). Through systematic synthesis, structure analyses, electrochemical characterizations, and computational modeling, this project will stablish the structure-property-activity relation of catalysts. Figure 1. Synthesis of nitrogen-doped carbon nano-onions (CNOs) and subsequent introduction of single metal atoms coordinated with 4 nitrogen atoms (M-N4).