Formation of Graphene Oxide Nanocomposites from Carbon Dioxide Using Ammonia Borane

To efficiently recycle CO2 to economically viable products such as liquid fuels and carbon nanomaterials, the reactivity of CO2 is required to be fully understood. We have investigated the reaction of CO2 with ammonia borane (AB), both molecules being able to function as either an acid or a base, to obtain more insight into the amphoteric activity of CO2. in the present work, we demonstrate that CO2 can be converted to graphene oxide (GO) using AB at moderate conditions. The conversion consists of two consecutive steps: CO2 fixation (CO2 pressure <3 MPa and temperature <100 degrees C) and graphenization (600-750 degrees C under 0.1 MPa of N-2). The first step generates a solid compound that contains methoxy (OCH3), formate (HCOO), and aliphatic groups, while the second graphenization is the pyrolysis of the solid compound to produce graphene oxide-boron oxide nanocomposites, which have been confirmed by micro-Raman spectroscopy, solid-state C-13 and B-11 magic angle spinning-nuclear magnetic resonance (MAS NMR), transmission electron microscopy (TEM), and atomic force microscopy (AFM). Our observations also show that the mass of solid product in CO2 fixation process and raw graphene oxide nanocomposites is twice and 1.2 times that of AB initially charged, respectively. The formation of aliphatic groups without using metal-containing compounds at mild conditions is of great interest to the synthesis of various organic products starting from CO2.