High Shear Conversion of Elemental Bismuth in Water Under Air to 2D Bismuth Oxycarbonate.

Abstract

2D Bismuth oxycarbonate (2D BOC) nanosheets have a unique layered structure with many applications, including capture and reduction of carbon dioxide. Processing powdered elemental bismuth in water under ambient air conditions using a vortex fluidic device (VFD) results in the formation of 2D BOC without the need of surfactants or other excipients. The induced high shear mechanical energy in the form of micron/submicron topological typhoon like spinning top (ST) fluid flow drives the conversion, which we propose initially melts the metal particles which are spontaneously oxidised at the liquid-quartz tube interface to form 2D bismuth oxide (Bi₂O₃). Then it reacts with atmospheric CO₂ to form 2D BOC. These sheets, ≤ 15.7 nm thick, are in the orthorhombic phase with a lattice spacing of 0.29 nm, which is converted to Bi₂O₃ monoclinic phase as an exothermic process at 269 °C.