Efficient and Selective Electroreduction of CO₂ by Single-Atom Catalyst Two-Dimensional TM–Pc Monolayers

Abstract

Electrochemical CO 2 reduction to value-added fuels and chemicals provides a "clean" and efficient way to mitigate energy shortages and to lower the global carbon footprint if one could find highly stable, efficient, selective, and low-cost electrocatalysts. However, this remains a huge challenge. In this work, the catalytic performance of transition metal−phthalocyanine (TM−Pc) monolayers as single-atom catalysts for the electroreduction of CO 2 was systematically investigated by spin-polarized density functional theory (DFT) calculations. Our results show that the bonding of single metal atoms with Pc can be large enough for the individual atoms to be uniformly dispersed and anchored in a modified 2D TM−Pc monolayer. Considering the competing hydrogen evolution reaction, TM−Pc has a good hydrogen evolution inhibition. The main CRR reduction products of Sc−Pc, Ti−Pc, V−Pc, and Fe−Pc monolayers are CH 4 . For Cr−Pc, Mn−Pc, and Zn−Pc monolayers, HCOOH is dominant, while for Co-Pc, HCHO is predicted. Except for the Sc−Pc, Ti−Pc, and V−Pc monolayers by (with too large overpotentials, exceeding 1 V), the reduction overpotential of other TM-Pc catalysts are in the range of 0.017−0.819 V, among them Mn−Pc has the lowest overpotential (0.017 V) and Fe−Pc has the highest overpotential (0.819 V). These were all lower than the overpotentials of well-studied copper which has the best catalytic performance. Therefore, our work may open up new avenues for the development of highly efficient catalytic materials for CO 2 reduction.

Densely Populated Single Atom Catalysts

“…However, to avoid agglomeration and maintain monodisperse metal atoms on the supports, the metal mass loading is usually below 1.5 wt%, which limits mass/volume activity of the catalysts . Generally, there are three key factors that significantly affect the mass loading of single atoms on the support: i) synthesis strategies, ii) precursors, and iii) substrates . For example, zinc single‐atom catalyst with an ultrahigh‐loading of 9.33 wt% has been successfully prepared by strictly controlling the gasification rate of ZnCl 2 precursor under a heating rate of 1 °C min −1 .…”

Efficient electrocatalytic reduction of carbon dioxide by metal-doped β12-borophene monolayers

“…[7][8][9][10][11][12] Due to their high specic surface area, reduced dimensionality and exotic properties, two-dimensional (2D) nanosheets have become an ideal platform for the design of novel electrocatalysts for CO 2 reduction. [13][14][15][16] Borophene is a novel 2D material under active investigation with fascinating and diverse properties and potential. 17 Recently, honeycomb borophene has been experimentally fabricated on an Al(111) substrate.…”

A Disquisition on the Active Sites of Heterogeneous Catalysts for Electrochemical Reduction of CO2 to Value‐Added Chemicals and Fuel

“…As a result, SAC catalysts demonstrate a higher atom efficiency, as well as a tunable coordination environments and electronic structures . In addition, SAC catalysts have the added benefit of exhibiting prominent surface area and exposes more active sites that allows enhanced electrocatalytic activity . Despite these advantages, SACs suffer from some disadvantages such as difficulty in synthesis and characterizations (typically synchrotron characterization is required to discern local electronic environment), as the high surface energy and reactivity of single atoms leads to aggregation as well as deactivation issues in presence of impurities .…”