We examined Ce–Mn mixed oxides as high-temperature desulfurization materials, exploring various Mn/Ce ratios and the effects of admixing other rare earth oxides. The sulfur capacities at temperatures from 900 to 1025 K with simple air regeneration were measured for repeat cycles until a stable, reversible capacity was obtained. The measured sulfur capacities with a realistic model syngas containing H2S, H2, N2, CO, H2O, and CO2 were compared to thermodynamically possible maximum sulfur capacities. The oxidized and sulfided (reduced) sorbents were characterized by X-ray diffraction (XRD), X-ray absorption near-edge spectroscopy (XANES), X-ray absorption fine structure (XAFS), temperature-programmed reduction (TPR), and Brunauer–Emmett–Teller (BET) surface area. Density functional theory calculations are used to aid in interpreting characterization data and in explaining the enhanced S adsorption capacities. There is a large synergistic effect on sulfur adsorption and reaction resulting from the intimate admixing of Mn with CeO2 and CeO2/La2O3 rare earth oxides. However, while these materials are stable at temperatures near 900 K, even using air regeneration, the observed stable sulfur capacities fall far short of predictions based on thermodynamic equilibrium. The differences are attributed to (a) inhibition by CO2 and H2O; (b) formation of some irreversible sulfates upon air regeneration; (c) inability of sulfur to diffuse into larger, sintered crystals of the mixed oxides; (d) gradual dissolution of Mn in an underlying support such as Al2O3 (when present).

CeO2–ZrO2 (CZO) nanoparticles (NPs) have applications in many catalytic reactions, such as methane dry reforming, due to their oxygen cycling ability. Ni doping has been shown to improve the catalytic activity and produces active sites for the decomposition of methane. In this work, Ni:CZO NPs were synthesized via a two-step co-precipitation/molten salt synthesis to compare Ni distribution, oxygen vacancy concentration, and catalytic activity relative to a reference state-of-the-art catalyst prepared by a sol–gel-adsorptive deposition technique. To better understand the dispersion of Ni and oxygen vacancy formation in these materials, the Ni concentration, position, and reaction time were varied in the synthesis. X-ray diffraction (XRD) measurements show a homogeneous, cubic phase with little to no segregation of Ni/NiO. Catalytic activity measurements, performed via a differential scanning calorimetry (DSC)/thermogravimetric analysis (TGA) method, displayed a 5-fold increase in the activity per surface area with an order of magnitude decrease in the coking rate for the particles synthesized by the molten salt method. Additionally, this approach resulted in an order of magnitude increase in oxygen vacancies, which is attributed to the high dispersion of Ni2+ ions in the NP core. This ability of controlling the oxygen vacancies in the lattice is expected to impact other such systems, which utilize the substrate redox cyclability to drive conversion via, e.g., a Mars–van Krevelen mechanism.

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batteries crucially relies on electrochemical characteristics of electrode materials, i.e., anode and cathode materials. [ 1 ] Various alternative anode materials have recently been developed, including silicon-based composites, [ 2,3 ] nanoscale transition metal oxides, [ 4,5 ] titanium-based materials, [ 6,7 ] and graphene-based sulfi de, [ 8 ] etc. These materials have demonstrated excellent rate capability and specifi c capacities several times higher than conventional graphite anodes. Since capacities of cathode materials are usually much lower than those of anodes, the cathode is considered as the limiting factor for lithium ion batteries. To a great extent, development of newgeneration lithium ion batteries is limited by the low energy density, low operating voltage, and poor rate capability of cathode materials. [ 9 ] Recently, the emerging Li-excess layered oxides have attracted a great deal of research efforts due to their high capacities. These cathode materials can be cycled over a broad voltage range between 2.0 and 4.8 V versus Li/Li + and deliver specifi c capacities higher than 250 mAh g −1 . They also offer many other advantages such as low cost, environmental benignity, and safety. [ 10 ] A representative example is Li-excess ternary manganese-nickel-cobalt oxide, composed

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Supercritical fluid extraction (SCFE)