The Hallmarks of Copper Single Atom Catalysts in Direct Alcohol Fuel Cells and Electrochemical CO2 Fixation

Single-atom catalysts (SACs) are highly enviable to exploit the utmost utilization of metallic catalysts; their efficiency by utilizing nearly all atoms to often exhibit high catalytic performances. To architect the isolated single atom on an ideal solid support with strong coordination has remained a crucial trial. Herein, graphene functionalized with nitrile groups (cyanographene) as an ideal support to immobilize isolated copper atoms G(CN)-Cu with strong coordination is reported. The precisely designed mixed-valence single atom copper (G(CN)-Cu) catalysts deliver exceptional conversions for electrochemical methanol oxidation (MOR) and CO2 reduction (CO2RR) targeting a "closed carbon cycle." An onset of MOR and CO2RR are obtained to be approximate to 0.4 V and approximate to-0.7 versus Ag/AgCl, respectively, with single active sites located in an unsaturated coordination environment, it being the most active Cu sites for both studied reactions. Moreover, G(CN)-Cu exhibited significantly lower resistivity and higher current density toward MOR and CO2RR than observed for reference catalysts.

This research was supported by receiving funding from the NAWA The Polish National Agency for Academic Exchange through Bekker grants PPN/BEK/2019/1/00348 "C1-C4 alkanes to oxygenated fuel electrochemical transformation" and PPN/BEK/2019/1/00345 "Nanostructured carbon-based materials doped with metal nanoparticles as catalytic electrode materials for CO2 electroreduction with the use of surface-plasmon enhancement". M.A.M.K. extends his sincere appreciation to Researchers Supporting Project at King Saud University for funding this Research (RSP-2020/130). R.G.K., A.B., O.T., M.P., M.O., R.Z., and M.B.G. gratefully acknowledge the support by the Operational Program Research, Development and Education -European Regional Development Fund (project no. CZ.02.1.01/0.0/0.0/16_019/000075 4) and by the ERDF project "Development of pre-applied research in nanotechnology and biotechnology" (project no. CZ.02.1.01/0.0/0.0/17_048/0007323) of the Ministry of Education, Youth and Sports of the Czech Republic. R.Z. and A.B. acknowledge the support from the Czech Science Foundation, project No. 19-27454X. M.O. acknowledges support by the H2020 ERC project no. 683024. The research activity of D.M. was supported by funds from the European Union's Horizon 2020 research and innovation program under the Marie Sklodowska-Curie grant agreement No. 711859 and by financial resources for science in the years 2017-2021 awarded by the Polish Ministry of Science and Higher Education for the implementation of an international co-financed project.