First principles investigation of cobalt-phthalocyanine active site tuning via atomic linker immobilization for CO2 electroreduction

We investigate the CO2 electroreduction reaction (CO2ERR) using first principles calculations, for the active site tuning of cobalt phthalocyanine (CoPc) via distinct atomic linker species which immobilize CoPc on a carbon nanotube (CNT) substrate. Eight different linker species are studied, along with the effect of linker hydrogenation. Superior reaction performance is predicted for the NH, S and PH linkers, which show activated CO2 adsorption. This results from spin polarization causing unoccupied dz2 spin -down states of the cobalt active site at, or above, the Fermi level. Using an 'on-catalyst' reaction scheme, calculated activation barriers for COOH formation and CO desorption are lower for the CoPc-PH-CNT sys-tem compared to the CoPc-NH-CNT system and CoPc remains attached to PH-CNT throughout the reac-tion. We thus expect the PH linker system to have similar or better CO2ERR performance compared to the NH and S linker systems but at a slightly higher electrode potential.(c) 2023 Elsevier Inc. All rights reserved.

Automated summary

We investigate the CO2 electroreduction reaction (CO2ERR) using first principles calculations, and explore the active site tuning of cobalt phthalocyanine (CoPc) immobilized on a carbon nanotube (CNT) substrate via various linker species. Our results show that NH, S, and PH linkers exhibit superior reaction performance, with activated CO2 adsorption due to spin polarization. The CoPc-PH-CNT system has lower activation barriers for COOH formation and CO desorption compared to CoPc-NH-CNT system, suggesting that PH linker system may have comparable or better CO2ERR performance at a slightly higher electrode potential.