The interaction between carbon nanotubes and organic molecules including benzene (C6H6), cyclohexane (C6H12), and 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ: C8N2O2Cl2) have been studied using first principles calculations. The equilibrium tube-molecule distance, adsorption energy, and charge transfer are obtained. The hybridization between the DDQ molecular level and nanotube valence bands transforms the semiconducting tube into a metallic one. Coupling of π electrons between tubes and aromatic molecules are observed. Our results show that noncovalent functionalization of carbon nanotubes by aromatic molecules is an efficient way to control the electronic properties of carbon nanotubes.

The redox behavior of ceria–zirconia solid solutions (or Zr-substituted ceria, ZSC) with a Zr content of up to 20 mol % is studied by thermogravimetry (TG) between 600 °C and 1490 °C under controlled atmospheres. Thermodynamic properties, specifically standard oxidation enthalpy, ΔH oxd ⊖, and entropy, ΔS oxd ⊖, are derived from TG data. The raw TG results show that the extent of reduction is significantly increased (compared with undoped ceria), even at a low Zr substitution level of 5 mol %. Concomitantly, the magnitude of the thermodynamic functions dramatically decreases as a function of Zr content, particularly at low values of oxygen non-stoichiometry, δ (<3 mol %). Thermochemical fuel production from Zr-substituted ceria generally increases with increasing Zr content under both two-temperature and isothermal cycling conditions. In the case of two-temperature cycling, the benefit is accompanied by a penalty in the (computed) steam-to-hydrogen conversion ratio, whereas it is accompanied by a gain in this ratio for isothermal cycling. Overall, introduction of Zr has the potential to enhance solar-driven thermochemical fuel production, depending on the details of cycling conditions and reactor design.

Solar-driven thermochemical water splitting using non-stoichiometric oxides has emerged as an attractive technology for solar fuel production. The most widely considered oxide for this purpose is ceria, but the extreme temperatures required to achieve suitable levels of reduction introduce challenges in reactor design and operation, leading to efficiency penalties. Here, we provide a quantitative assessment of the thermodynamic and kinetic properties of La 1Àx Sr x MnO 3Àd perovskites, targeted for a reduced temperature operation of thermochemical water splitting. Sr-doping into lanthanum manganite increases the thermodynamic fuel production capacity, which reaches 9 ml g À1 for 0.

It has long been established that by filling carbon nanotubes or coating on their surfaces with tran-sition metals, one-dimensional hybrid nanostructures can be synthesized. We found through ab initio calculations that such transition-metal/nanotube hybrid structures exhibit substantial magnetism. In particular, cobalt atoms packed inside a variety of carbon nanotubes offer strong spin polarization at the Fermi level as well as considerable magnetic moments. The results point to a new and promising approach that uses such metal-filled carbon nanotubes as devices for spin-polarized transport and to potential applications in the emerging field of spintronics.