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The water vapor (WV) influence on the reactivity and capacity of three commonly used oxygen carriers (OCs), iron, nickel, and copper based on chemical looping combustion, was investigated. OC samples with increasing metal loadings on the alumina support were prepared through freeze granulation (FG) and evaluated by a thermogravimetric analyzer−mass spectrometer coupled water vapor generator system (WVG−TG−MS) under cycling reducing−oxidizing gases at 950 °C. The comparative study in dry and wet simulated syngas showed that the reactivity and oxygen carrying capacity was reduced to varying extents for the three types of carriers by the addition of 10% WV. Under dry conditions, the copper-and nickel-based carriers showed higher reactivity and larger capacity in the reduction and oxidation cycles than iron-based carriers. However, the iron-based carriers presented better resistance to the WV influence than the other two. Under the wet condition, the performance difference among the three types of OCs became less significant. Metal loadings were also found to affect the resistance of carriers to the presence of WV. A series of direct coal combustion experiments was performed in the TGA−MS system as well to study the effect of WV in solid-fueled combustion. The rate of weight loss of the OC/char mixture in Ar with 10% WV at 950 °C was approximately 4 times faster than that in dry Ar, suggesting that the presence of WV promoted in situ char gasification and increased the overall reaction rate and completeness of the solid fuel combustion.

The cross-coupling reaction of organometallic reagents with organic halides and related electrophiles represents one of the most straightforward methods for carbon-carbon bond formation (Scheme 1-1). Despite its inherent simplicity and significance, however, its synthetic utility was very limited until the mid-1960s. Mainly Grignard reagents and organolithiums were used in earlier examples. In such cases, organic halides are mostly limited to alkyl (C,3) halides. Furthermore, the use of organometals containing Mg and Li is often complicated and limited by their generally low chemoselectivity. Although advances in organocopper chemistry [l] over the past three decades have solved many of the difficulties associated with the use of Grignard reagents and organolithiums, a number of other problems have remained unsolved.In 1972, Kumada [2] and Corriu [3] independently reported that the reaction of Grignard reagents with alkenyl or aryl halides could be markedly catalyzed by Ni-phosphine complexes, e.g., Cl,Ni(PPh,),. Although many other transition-metal-catalyzed reactions of Grignard reagents with organic halides without the use of phosphines were known, the socalled Kharasch-type reactions [4], with the exception of the Cu-catalyzed procedures [5,6], were not well suited for cross-coupling due to various complications, including extensive cross-homo scrambling.The discovery of Pd-catalyzed cross-coupling was somewhat more subtle and evolutionary. During the 1975-1976 period, several groups of workers including the present authors' group published various results involving Pd-phosphine complexes. Thus, Cassar "71 reported the Pd-catalyzed cross-coupling reaction of aryl bromides and iodides with sodium acetylides generated in situ by mixing terminal alkynes with NaOMe in DMF (Scheme 1-2). The corresponding reaction using a Ni-phosphine complex did not proceed Catalytically. Similar reactions of alkynes, where the countercations in active species were most probably ammonium and/or Cu', were also reported by Heck [8] and Sonogashira [9] (Scheme 1-2).

A 3D flower-like NiO/Ni composite was prepared by a facile, template-free, hydrothermal method followed by calcination in N 2 atmosphere in the presence of glucose. The particles are assembled from porous nanoflakes. XRD, SEM, TEM, and X-ray photoelectron spectroscopy were performed to characterize the morphology and composition of the material. This revealed that during the calcination process NiO was partially transformed into Ni and consequently an NiO/Ni composite was obtained. Cyclic voltammetry, galvanostatic charge/discharge, and electrochemical impedance spectroscopy were conducted in 6 M KOH electrolyte solution. This showed that the NiO/Ni composite exhibits a higher specific [a]

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