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Two CO2 solid sorbents based on polyethylenimine, PEI (M(n) ∼ 423 and 10K), impregnated into mesoporous silica (MPS) foam prepared in kilogram quantities via a scale-up process were synthesized and systematically characterized by a range of analytical and surface techniques. The mesoporous silica sorbent impregnated with lower molecular weight PEI, PEI-423/MPS, showed higher capacity toward CO2 sorption than the sorbent functionalized with the higher molecular weight PEI (PEI-10K/MPS). On the other hand, PEI-10K/MPS exhibited higher thermal stability than PEI-423/MPS. The kinetics of CO2 adsorption on both PEI/MPS fitted well with a double-exponential model. According to this model CO2 adsorption can be divided into two steps: the first is fast and is attributed to CO2 adsorption on the sorbent surface; the second is slower and can be related to the diffusion of CO2 within and between the mesoporous particles. In contrast, the desorption process obeyed first-order kinetics with activation energies of 64.3 and 140.7 kJ mol(-1) for PEI-423/MPS and PEI-10K/MPS, respectively. These studies suggest that the selection of amine is critical as it affects not only sorbent capacity and stability but also the energy penalty associated with sorbent regeneration.

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H2 and NH3 were produced when a suspension of Fe203 catalyst particles or sintered pellets in water were illuminated with light of energy greater than 2.3 eV. Catalytic action was demonstrated by detecting H2 yields many times the stoichiometric equivalent of the measured (by X-ray diffraction, Móssbauer spectroscopy, and oxidimetry) Fe(II) content of the catalyst, up to 80X for H2 and 20X for NH3. The initial rate of formation of H2 was 40 µ /h-g of catalyst and of NH3 was 10 µ /h-g of catalyst. The formation

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The thermodynamics of oxidation and reduction were investigated for a series of vanadium-containing oxides, including CeVO 4 , LaVO 4 , ZrV 2 O 7 , Mg 3 (VO 4 ) 2 , CrVO 4 , AlVO 4 , and V 2 O 5 , in the temperature range between 873 and 973 K, using coulometric titration to measure oxidation isotherms. For each of the compounds, the oxygen uptakes corresponded to oxidation from V +3 to V +5 as oxygen fugacities increased from 10 -25 to 10 -2 atm. With V 2 O 5 and ZrV 2 O 7 , the only materials in this group that contain V-O-V linkages, there was evidence for two oxidation processes, corresponding to V +3 -V +4 and V +4 -V +5 equilibria, whereas oxidation occurred in a single step for the other materials. CrVO 4 and AlVO 4 were unstable to deep reduction, but oxidation enthalpies and entropies were reported for CeVO 4 , ZrV 2 O 7 , Mg 3 (VO 4 ) 2 , and V 2 O 5 .

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