Boosting CO<sub>2</sub> Activation and Reduction by Engineering the Electronic Structure of Graphitic Carbon Nitride through Transition Metal-Free Single-Atom Functionalization
Syed Fozia, Afshana Hassan, Showkat Ahmad Reshi, Priti Singh, Gulzar A. Bhat, Mudit Dixit, Manzoor Ahmad Dar
Abstract
In recent years, electrochemical reduction of CO 2 to high-value chemicals and fuels using carbon-based two-dimensional materials has emerged as a promising alternative for reducing the atmospheric CO 2 levels and addressing global energy challenges. However, rationally tuning the electronic structure of these materials for optimizing their catalytic performance remains a great challenge. Herein, using first-principles simulations, we investigate the electronic and catalytic properties of the single atom (SA)-functionalized graphitic carbon nitride (g-C 2 N) monolayer for CO 2 activation and reduction. Our results reveal that SA substitution leads to effective activation and capture of CO 2 . In-depth electronic structure analysis based on the crystal orbital Hamilton population (COHP) and integrated density of states unraveled the atomic-level details of the interaction of CO 2 with the SA-substituted monolayers. Furthermore, the simulated reaction pathways demonstrate that the Al-SAC is highly proficient for CO 2 conversion to HCOOH, whereas the B-SAC reduces CO 2 to CH 3 OH with a record-low limiting potential of −0.45 V. In addition, the Al- and B-SACs effectively suppress the competitive hydrogen evolution reaction (HER), making CO 2 reduction highly selective on these catalysts. Furthermore, the small CH 3 OH desorption energy of 0.73 eV on the B-SAC makes it a suitable candidate for CO 2 reduction to methanol. Thus, our findings not only provide theoretical guidance for accelerating the design of new and promising catalysts for CO 2 reduction but also elucidate the structure–activity correlations.