We describe a simple drop-cast processing method to synthesize multicomponent polymer-based nanocomposites for carbon dioxide (CO2) capture and conversion into stable carbonates. These multicomponent nanocomposites are made of combination of different metal oxide nanoparticles and catalysts in a porous polymer matrix. The formulation includes the combination of titanium dioxide and magnesium oxide, ruthenium oxide, and iron oxide where each metal oxide exhibits its own catalytic function of trapping carbon dioxide. Such a material system provides numerous localized catalytically active hot reaction spots generated by the dispersed multifunctional oxide nanoparticles that react with CO2 when exposed to the gas stream and instantaneously convert the captured carbon into carbonates. Finally, we discuss our ongoing work on the possibility of converting captured-carbon-formed-carbonate into useful products/commodities such as methane, methanol and formic acid. The integration of polymer materials with catalytically active nanomaterials shows a promising strategy for CO2 capture and conversion into useful products towards achieving a sustainable energy future.

Fluorine substitution in CaH2 has been studied by means of experimental and theoretical methods. Samples with various compositions have been prepared by ball milling. In situ X-ray diffraction analysis has been carried out as a function of temperature by synchrotron radiation experiments. An increase of mixing has been observed during heating, suggesting that mixing is thermodynamically favoured but it is kinetically hindered at low temperatures. Ab initio DFT calculations have been performed to estimate the thermodynamic mixing properties of both orthorhombic and cubic solid solutions. On the basis of ab initio results and literature information, a thermodynamic assessment within the CALPHAD framework has been performed and the pseudo binary CaH2-CaF2 phase diagram has been calculated. The formation of orthorhombic and cubic terminal solid solutions in the CaH2-CaF2 system is predicted, in good agreement with experimental findings.

LiBH4 and MgH2 both have high gravimetric and volumetric hydrogen storage densities. Unfortunately, their commercial application is prevented by high thermal stability and unfavorable thermodynamic properties. Combining the two hydrides leads to a new decomposition pathway with suitable enthalpy of reaction. However, the kinetics for hydrogen release remains an obstacle but can be improved by nanoconfinement in nano porous carbon materials. Here we report on nanoconfinement of 2LiBH4-MgH2 in Ni functionalized carbon aerogels. 11B MAS NMR reveals that the nanoconfined hydrides react reversibly with hydrogen whereas simultaneous differential scanning calorimetry and mass spectroscopy clearly show that nanoconfinement facilitates lower hydrogen release temperatures than ball milling. Furthermore, Ni functionalization of the nanoporous aerogel leads to even lower hydrogen release temperatures from nanoconfined 2LiBH4-MgH2.

Cerium in various chemical forms was introduced into NaAlH4 to study the hydrogen sorption properties of the resulted material. Although all the Ce precursors tested in this work resulted in a reversible hydrogen storage material, an immediate enhancement in the desorption kinetics could be achieved by a heating treatment, resulting in the in situ formation of cerium aluminide (CeAl4) in the material. While the use of CeAl4 instead of CeCl3 can increase the hydrogen capacity by bypassing the formation of the ineffective NaCl, the highest capacity of 4.9 wt% was obtained from NaAlH4 doped directly with commercial metallic cerium, which may provide a much simplified process for a possible up-scaling preparation of this hydrogen storage material.