The solubility of carbon dioxide (CO2) in five tetraalkylphosphonium superbase ionic liquids, namely the trihexyltetradecylphoshonium phenoxide, trihexyltetradecylphoshonium benzotriazolide, trihexyltetradecylphoshonium benzimidazolide, trihexyltetradecylphoshonium 1,2,3-triazolide and trihexyltetradecylphoshonium 1,2,4triazolide was studied experimentally under dry and wet conditions at 22 °C and at atmospheric pressure using a gravimetric saturation technique. The effects of anion structure and of the presence or absence of water in solution on the carbon dioxide solubility were then deduced from the data. 1 H and 13 C-NMR spectroscopy and ab initio calculations were also conducted to probe the interactions in these solutions, as carbon dioxide and water can compete in the ionic liquid structure during the absorption process. Additionally, the viscosity of selected superbase ionic liquids was measured under dry and wet conditions in the presence or absence of CO2 to evaluate their practical application in carbon dioxide capture processes. Finally, the recyclability of the trihexyltetradecylphoshonium 1,2,4-triazolide under dry and wet conditions was determined to probe the ability of selected solvents to solubilize chemically a high concentration of carbon dioxide and then release it within a low energy demand process.

Sustaining metal-organic frameworks for water-gas shift catalysis by non-thermal plasma. Nature Catalysis.

A new low-energy pathway is reported for the electrochemical reduction of CO2 to formate and syngas at low overpotentials, utilizing a reactive ionic liquid as the solvent. The superbasic tetraalkyl phosphonium ionic liquid [P66614][124Triz] is able to chemisorb CO2 through equimolar binding of CO2 with the 1,2,4-triazole anion. This chemisorbed CO2 can be reduced at silver electrodes at overpotentials as low as 0.17 V, forming formate. In contrast, physically absorbed CO2 within the same ionic liquid or in ionic liquids where chemisorption is impossible (such as [P66614][NTf2]) undergoes reduction at significantly increased overpotentials, producing only CO as the product.

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The sidewalls of vertically aligned, multiwalled carbon nanotubes were functionalized using azide photochemistry, and DNA oligonucleotides were synthesized in situ from the reactive group on each photoadduct to produce water-soluble DNA-coated nanotubes. The functional DNA sites on the nanotubes were visualized from gold nanoparticles modified with complementary DNA and using TEM. The sidewall functionalization enabled further DNA-directed modification of the nanotubes' surfaces with nanoparticles. The DNA-coated vertically aligned nanotubes offer the architecture for a highly loaded three-dimensional DNA chip.