CO2 Capture by Nickel Hydroxide Interstratified in the Nanolayered Space of a Synthetic Clay Mineral

Clay minerals can adsorb large amounts of CO2 and are present inanthropogenic storage sites for CO2. Nanoscale functionalization of smectite clayminerals is essential for developing technologies for carbon sequestration based onthese materials and for safe guarding relevant long term carbon storage sites. Weinvestigate the adsorption mechanisms of CO2 in dried and hydrated synthetic Ni exchangedfluorohectorite clay using a combination of powder X ray diffraction,Raman spectroscopy, and inelastic neutron scattering. Both dried and hydrated Ni exchangedfluorohectorite show crystalline swelling and spectroscopic changes inresponse to CO2 exposure. These changes can be attributed to interactions with [Ni OH 0.83 H2O 1.17]0.371.17 interlayer species, and swelling occurs solely in theinterlayers where this condensed species is present. The experimental conclusions aresupported by density functional theory simulations. This work demonstrates ahitherto overlooked important mechanism, where a hydrogenous species present inthe nanospace of a clay mineral creates sorption sites for CO