A rational design of covalent organic framework supported single atom catalysts for hydrogen evolution reaction: A DFT study

Abstract

Excessive consumption of fossil fuels and CO2 emissions exacerbate global environmental concerns. Unfortunately, fossil fuel reserves are dwindling and fossil fuel energy is unsustainable, non-renewable, and costly. Due to these concerns, there is an imperative demand for eco-friendly energy conversion electrochemical systems. Hydrogen (H2) is ubiquitously regarded as a fossil fuel substitute and a potential sustainable energy source. Water electrolysis powered by renewable resources is being considered as a sustainable approach to produce H2. To cater the need, electrocatalysts with non-precious single metal atoms supported on a covalent organic framework (TM@COF SACs) have been proposed for HER. Single atoms of Co, Ni, Cu, and Zn were introduced onto the COF substrate. The thermodynamic stability, HOMO, LUMO energies, HOMO-LUMO energy gaps, DOS spectra, and change in the Gibbs free energy of adsorbed atomic hydrogen (ΔGH∗) on the catalyst's surface are used to evaluate the catalytic performance of designed complexes for HER. Among all the considered complexes, Zn@COF demonstrated the highest potential to act as a single atom catalyst, with an Eint value of −0.11 eV. Density functional theory (DFT) findings suggest that single Zn atom doped on the surface of the covalent organic framework with ΔGH∗ value of −0.88 eV has a substantial effect on the performance of the HER. This research opens up new possibilities for the advancement and utilization of highly efficient, stable, and cost-effective single-atom catalysts for HER, thereby laying the foundation for future developments in this field.