In this work, starch has been used to enhance the oxygenate formation directly from methane and carbon dioxide using dielectric-barrier discharges (DBDs). The use of starch inhibits the formation of liquid hydrocarbons and significantly increases the selecti

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A lot of attentions have been recently paid to the CO2 reforming of methane to syngas. A major reason for it is that this reaction can provide us a syngas with a 1/1 ratio of H2 and CO, which is typically suitable for the synthesis of valuable oxygenated chemicals.1 Among the catalysts developed, Al2O3 supported Ni catalysts were extensively investigated due to their relatively high activity and low cost. The major problem for the further practical application of these nickel catalysts is the deactivation of the catalyst, suffered from carbon deposition on the catalyst during reactions. Many investigators are working on the improvement in this nickel catalyst by using the addition of promoters,2, 3 using novel reactor configurations,4 and using different supports.3 In this work, we attempt to use an AC corona discharge plasma for the CO2 reforming of methane to syngas. A stable operation of plasma CO2 reforming of methane has been achieved.

A density functional theory (DFT) study has been conducted to investigate the structural and electronic properties of PdO/HZSM-5 and thereby the relationship between PdO and the acid sites of HZSM-5. Different cluster models of PdO/HZSM-5 based on experimental and theoretical works are presented. The study shows that the local structure of PdO supported on HZSM-5 is very similar to the four-coordinated square planar structure of bulk PdO. This is consistent with the reported EXAFS analysis in the literature. The average distances between the Pd and the four coordinated oxygen atoms obtained by DFT calculations with different cluster models are close to the reported experimental results. The analysis of the Mulliken population and the electron density difference of the cluster models shows that there exists a charge transfer from the four coordinated oxygen atoms to the Pd. The components of the frontier molecular orbital of these cluster models come mainly from the Pd and the four coordinated oxygen atoms. The DFT study confirms that the acid sites in HZSM-5 keep the PdO well dispersed due to the bond interaction between the acidic proton atom and the oxygen atom of PdO. In addition, after the formation of PdOH+, the acidity of HZSM-5 complex remains high or in some instances increases.

The combination of catalyst and non-thermal plasmas has led to some unusual chemical behaviors, especially with zeolite catalyst. A mechanism has been proposed to explain the observed interaction between catalyst and non-thermal plasmas. This mechanism includes two aspects: plasma promoted or induced catalysis and catalyst enhanced non-equilibrium of nonthermal plasmas. In this paper, we present some direct experimental evidence for the catalyst (zeolite)-enhanced non-equilibrium of non-thermal plasmas suggesting the use of zeolite increases, significantly, the electron temperature of non-thermal plasmas, while the gas temperature remains unchanged. A floating double-probe characteristic has been utilized to measure the electron temperature. Compared to the case without zeolite, the electron temperature of non-thermal plasmas with Mo-Zn/HZSM-5 increases up to 250%, while, at the same time, the discharge power reduces 58%, compared to that without zeolite. r 2002 Elsevier Science B.V. All rights reserved.