Graphene oxide lowers carbon monoxide polymerization pressure through chemical pre-compression†

Abstract

Polymeric carbon monoxide (p-CO) is one of only a few low-Z extended solids that form under high pressure and can be recovered under ambient conditions. As an innovative carbon-based material with potential applications, its development is restricted by the harsh synthesis conditions and metastability. Motivated by the application of two-dimensional (2D) materials to facilitate reduction reactions of N₂ and CO₂, the metal-free initiators/catalysts, graphene and graphene oxide (GO), were introduced into the carbon monoxide (CO) system under high pressure to investigate their effects. Our ab initio theoretical study demonstrates that GO can provide chemical force to “pre-compress” the CO molecules and greatly lower the polymerization pressure from 5 GPa to 3 GPa (a 40% decrease). The catalytic mechanism analysis elucidates that GO can significantly reduce the free energy barrier for the CO dimerization reaction, which is the most challenging step in the CO polymerization process. Moreover, the introduction of GO can effectively improve the stability of p-CO via forming C–C bonds, H-bonds and H-transfer at the GO-CO interface. Our study presents a novel approach for achieving condensed matter under milder conditions and extends the application of 2D materials as initiators to high-pressure synthesis, contributing to their potential application as energetic materials of p-CO.