Molecular Design of Dispersed Nickel Phthalocyanine@Nanocarbon Hybrid Catalyst for Active and Stable Electroreduction of CO<sub>2</sub>
Zisheng Zhang, Yang‐Gang Wang
Abstract
The molecular catalyst/nanocarbon hybrid through π–π stacking immobilization is an emerging family of single-atom catalysts with outstanding performance in electrocatalysis, well-defined active site, and tunability at molecular level through functional group substitution. In the present work, we provide a general strategy for the rational design of molecular single-atom catalyst in the form of nickel phthalocyanine@nanocarbon (NiPc@NC) for highly efficient electroreduction of CO2 to CO. We employ density functional theory (DFT) calculations and state-of-the-art electronic structure analysis to explore the mechanism and substituent effects on structural stability, redox chemistry, adsorption properties, and molecule–substrate interactions of the NiPc catalyst. We have revealed that the electron-withdrawing groups facilitate the reductive activation of the catalytic Ni center but weaken the Ni–N bond strength and make the CO desorption sluggish, while the electron-donating groups do the opposite. A substituent-dependent correlation between interaction strength and electron transfer through the interface is also revealed by noncovalent interaction analysis and electron density difference projection. On the basis of the gained insights, we apply semiempirical quantum mechanical (SQM) calculation, machine learning (ML), and genetic algorithm (GA) to screening through the chemical space of ca. 10 trillion substituted NiPc molecules under a descriptor scheme to identify promising molecular candidates for the NiPc@NC hybrid material. The best candidate from GA search outperforms the state-of-the-art catalyst in terms of stability, reduction potential (improved by 110 mV), and interaction with substrate (strengthened by 0.46 eV). Design strategies are proposed based on the top-scoring molecules from computational screening, and the workflow is highly generalizable and transferable to similar molecular systems for other applications.