CO₂ conversion on defect-induced single-layer <i>h</i>-BN

Finding effective heterogeneous catalysts, consisting of abundant elements, for hydrogenation of waste gas carbon dioxide into value added molecules is a challenging task for global energy and sustainability solutions. In this talk, we will present results of a closely coupled computational and experimental effort that shows that reconfiguration of the frontier orbital in defect-laden hexagonal boron nitride (dh-BN) can effectively activate the CO₂ molecule for hydrogenation. Our density functional theory (DFT) based calculations of reaction pathways and activation energy barriers demonstrate that activation occurs through back-donation to the π* orbitals of CO₂ from frontier orbitals (defect state) of the h-BN sheet localized near a nitrogen vacancy (V_N). Subsequently, CO₂ is hydrogenated to formic acid (HCOOH) and methanol (CH₃OH). These results were experimentally confirmed in a reactor designed to continuously produce defects in h-BN by the application of mechanical force. We find temperature-dependent switchable catalysis with formic acid formation observed at reaction temperatures above 160 ^οC and methanol formation at lower temperatures (as low as 20 ^οC).