CO₂ Activation and Capture on a Si-Doped h-BN Sheet: Insight into the Local Bonding Effect of Single Si Sites

Abstract

Inert CO2 is only physically adsorbed on the surface of h-BN and graphene two-dimensional (2D) materials. However, a Si-doped h-BN sheet is able to capture CO2 directly through chemisorption under mild conditions. Herein, first-principles calculations and ab initio molecular dynamics (AIMD) simulations have been performed to explore the interaction between CO2 and the Si-doped h-BN sheet, and CO2 activation and chemisorption at the SiN3 site are predicted to be exothermic (−0.22 eV) and almost barrier free (0.03 eV). Such high activity of the single Si site toward CO2 activation strongly depends on its local bonding environment, and there are only weak van der Waals interactions between CO2 and SiB3 and SiC3 units of Si-doped h-BN and graphene sheets. The present calculations reveal that the Si-p z dangling bond dominates the Si–CO2 bonding interaction in CO2 chemisorption on the Si-doped h-BN sheet, and facile activation and capture of CO2 require the low-energy p z band of Si.

Anti-Electrostatic Main Group Metal–Metal Bonds That Activate CO2

“…Considering the dual role of the Al center in (BDI)­Al­(I) ( 1 ) as both a Lewis base and a Lewis acid, we expect that this compound could aid in the capture and activation of CO 2 . Computationally, it has been shown that the Si center of SiN 4 dispersed on a two-dimensional SiN 4 C 4 monolayer or doped on an h-BN sheet, which has an electronic structure similar to that of Al­(I), can effectively capture and activate CO 2 . , Geometry optimization of (BDI)­Al­(I) with CO 2 ( 1 -CO 2 ) at the M06-2X-D3/6-311++G­(d,p) level shows that CO 2 is perpendicular to the six-membered ring with one oxygen approaching Al from the top and the carbon bonding to Al in the plane (Figure ). Remarkably, the initially linear OCO angle bends to 125.6° and the CO bond involved in the interaction with the Al center is stretched from 1.155 to 1.390 Å, close to the single C–O bond distance of 1.43 Å in esters.…”

The Influence of Single-Atom Fe2+/3+N4 Spin State on the Electroreduction of CO2 to CO/HCOOH by Analyzing Proton/Electron Transfer Mechanisms and Free Energy Evolutions

“…The growing global climate change caused by the excessive emission of carbon dioxide (CO 2 ) is triggering a tragic environmental crisis and threat to social development. − Electrochemical reduction of CO 2 (CO 2 RR) to valuable chemical fuels under ambient conditions has been proved to be a particularly appealing proposal for achieving carbon-neutral energy cycle, which is powered by the electricity generated from renewable energy sources. − However, there still remains a grand challenge to render the broad application of the early stage technology due to the robust chemical inertness of CO 2 with two extremely stable CO bonds and the competition of the hydrogen evolution reaction (HER) in aqueous electrolytes. − Therefore, it is imperative to develop economically viable catalysts with high catalytic activity and product selectivity.…”

Chemical Bonding and Activity of Atomically Dispersed Silicon in Two- and Three-Dimensional Materials

“…Lee et al introduced Si dopants during the CVD growth process of graphene and successfully synthesized Si-doped graphene sheets . Inspired by these remarkable advancements, we designed various 2D monolayers with the atomically dispersed Si, including a Si-doped h-BN sheet and a series of Si-coordinated N-doped graphene monolayers, and further explored their applications to activation and electrochemical reduction of CO 2 . , …”

“…Previous studies have explored its potential for CO 2 capture and activation, although CO 2 could be only physically adsorbed on the h-BN surface . To address this limitation, we tried to introduce atomically dispersed Si sites into the h-BN sheet to promote its activity toward CO 2 activation, and thus a Si-doped h-BN sheet containing SiN 3 moiety by replacing B with Si was constructed, as shown in Figure a . The first-principles calculations revealed that the atomically dispersed Si site indeed can activate CO 2 to yield a chemisorption configuration of CO 2 with a remarkably low energy barrier of 0.03 eV.…”

“…Optimal structure of Si-doped h-BN sheet (a) and relative energies of two CO 2 adsorbed on a multiple-Si-doped h-BN sheet (b). Reprinted with permission from ref . Copyright 2021, American Chemical Society.…”