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Ni–Fe/Al2O3 catalyst for partial oxidation of methane was prepared first by glow discharge plasma treatment following by calcinations thermally. Such prepared catalyst exhibits better performance over the catalyst prepared without such plasma treatment. The conversion of methane and the selectivity of CO and H2 over the plasma treated catalyst are 97.44, 100 and 100% at 875 °C, while, at the same temperature, they are 90.09, 97.28 and 97.09%, respectively, over the catalyst prepared without plasma treatment. At the same methane conversion, the reaction temperature with the plasma treated Ni–Fe/Al2O3 is at least 80 °C lower. TEM characterization shows that the catalytically active species after plasma treatment are still highly dispersed on the support. In addition, the plasma treated Ni–Fe/Al2O3 catalyst also possesses better anti-carbon deposit ability. [Copyright &y& Elsevier]

In this work, a novel glow discharge plasma treatment of Pd/HZSM-5 catalyst, followed by calcination thermally, has been conducted. Such prepared catalyst presents a higher catalytic activity and an enhanced stability over the catalyst prepared without plasma treatment. The methane conversion over the plasma treated catalyst is close to 100% at 450 °C, but it is only ca. 50% at the same temperature over the catalyst without plasma treatment. The XPS, H2 chemisorption and XRD characterizations confirm an enhanced dispersion has been achieved with the plasma reduction (during treatment) followed by oxidation (during calcination). Upon FT-IR analyses, the plasma treatment, followed by calcination thermally, also leads to enhanced Bro¨nsted and Lewis acidities. The amount of Bro¨nsted acid sites of the plasma treated Pd/HZSM-5 catalyst is 1.13 times larger than that of the catalyst without plasma treatment, while the amount of Lewis acid sites of the plasma treated Pd/HZSM-5 catalyst is 1.21 times higher. The enhanced acidities are definitely helpful to increase the dispersion of PdO over the support and improve the interaction between PdO and HZSM-5 support, which leads to a remarkable improvement in the catalyst stability. [Copyright &y& Elsevier]

A novel method for starch modification is investigated. Starch is highly cross linked by glow discharge plasma, without the assistance of conventional chemical agents, thus avoiding any environmental concerns. An energy-charge-transfer mechanism is suggested for the function of plasma. This process could be useful for the production of large quantities of modified starch. [Copyright &y& Elsevier]

A novel Pd/HZSM-5 catalyst was prepared first by glow discharge plasma treatment followed by calcination thermally. Such prepared catalyst shows a higher activity and an enhanced stability for methane combustion. The XRD characterization and XPS analysis confirm that the plasma preparation leads to a better preparation of PdO active species over the HZSM-5 support. Especially, a plasma-enhanced acidity has been achieved upon the FT-IR analysis. The enhanced acidity plays an important role in stabilizing the dispersed PdO active species on the zeolite support. [Copyright &y& Elsevier]

Abstract: Shape controlled Au nanocrystal growth in ionic liquid has been studied by glow discharge plasma reduction. In an 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) solution with poly(vinyl pyrrolidone) (PVP) as surfactant, Au nanocrystals grow from faceted NPs to peanut-like particle aggregates, and eventually worm-like nanorods and nanowires as the growth time increases. This process is further found to be dependent on the concentration of employed surfactant. Based on systematic microscopic analysis and control experiments, a polymer-assisted oriented attachment mechanism is proposed to explain the observed morphologic evolution. Our work may have great implications for the employment of ionic liquids for shape controlled synthesis of nanocrystals. [Copyright &y& Elsevier]

Abstract: In this work, diffuse reflectance infrared Fourier transformation (DRIFT) spectroscopy of adsorbed CO was studied to investigate the stability of Pt/ZrO2 catalysts for partial oxidation of methane. The studies confirmed that the preparation method has a significant effect on the catalyst performance and the catalyst treatment using argon glow discharge plasma improves the catalyst stability. TG analysis showed that coke formation is not significant on both samples with and without glow discharge plasma treatment, indicating the coke formation is not responsible for the catalyst deactivation. The IR band intensity of adsorbed CO decreases remarkably with increasing calcination temperature, suggesting the sintering of Pt particles in the presence of O2. The sintering of plasma treated sample is slower than that of the untreated sample, especially at higher temperature, which indicates that the plasma treated sample is more resistant to sintering under the oxidizing atmosphere. [Copyright &y& Elsevier]

Abstract: In this work, characterizations using X-ray powder diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) confirm that argon glow discharge plasma can effectively reduce the Al2O3 supported Ir catalyst without the use of any conventional reducing chemicals. Such plasma-reduced Ir/Al2O3 catalyst shows a significantly enhanced dispersion. High conversions have been achieved on this plasma-reduced Ir/Al2O3 catalyst for CO2 reforming of methane. [Copyright &y& Elsevier]

Abstract: Pd/HZSM-5 catalysts prepared via glow discharge plasma reduction followed by calcination thermally show excellent enhanced stability for methane combustion. EXAFS characterization confirms that argon glow discharge reduces Pd/HZSM-5 catalyst effectively at close to room temperature. After thermal calcination of argon plasma reduced Pd/HZSM-5 catalyst under air, specific tetragonal PdO species are formed. This kind of active PdO species keeps stable during methane combustion, which leads to the observed excellent stability of plasma prepared Pd/HZSM-5 catalyst. EXAFS characterization also shows argon plasma reduction can help to remove Cl, which has a negative effect on catalysts properties. [Copyright &y& Elsevier]

Abstract: In this work, we reported a new plasma catalyst preparation method for carbon nanotube (CNT) formation. With this new method, argon glow discharge plasma was operated at room temperature and applied for the reduction of Pd/HZSM-5, instead of catalyst reduction thermally using hydrogen at elevated temperature. Such plasma reduced catalyst shows a high dispersion of metal particles. The multi-walled CNTs produced with this plasma reduced Pd/HZSM-5 exhibit structural graphene sheets in conical hollow shape, a typical structure observed in CNTs from catalytic methane decomposition. Some fiber fish bone type structures can be also observed. Compared to the hydrogen reduction (thermally), the reduction using argon plasma is feasible and effective for the preparation of catalyst for the CNTs formation. The glow discharge plasma catalyst reduction is very promising for the further development of green catalyst reduction technologies. [Copyright &y& Elsevier]

Abstract: Ni/Al2O3 catalyst was first treated by argon glow discharge plasma followed by calcination in air. The catalyst prepared this way exhibits an improved low-temperature activity for carbon dioxide reforming of methane, compared to the catalyst prepared without plasma treatment. The catalyst characterization using XRD, chemisorption and TEM analyses show that the plasma treatment followed by calcination thermally induces a generation of specific nickel species on the support. This kind of “plasma” metal species is highly dispersed on the support and can remain stable during reforming reactions. The average size of the “plasma” metal particles is ca. 5nm. The plasma treatment can also enhance the anti-carbon deposition performance of the catalyst. The formation of carbon species that is responsible for catalyst deactivation can be inhibited. The catalyst stability is therefore improved. [Copyright &y& Elsevier]

A novel catalyst preparation for NO reduction by CH4 has been conducted using a glow discharge plasma treatment followed by calcinations thermally. Such plasma prepared Pt/NaZSM-5 catalyst exhibits a high dispersion of metal active species. A remarkable improvement in the activity and stability, compared to the catalysts prepared conventionally, has been achieved. Especially, an excellent low temperature activity over the plasma-treated Pt/NaZSM-5 catalyst has been obtained. For example, the conventional 0.1 wt% Pt/NaZSM-5 catalyst shows no activity at temperatures below 673 K, while at 673 K, the NO conversion to nitrogen reaches 61.3% over the plasma-treated 0.1 wt% Pt/NaZSM-5 catalyst. The initiated temperature for the plasma-treated 0.1 wt% Pt/NaZSM-5 catalyst can be as low as 548 K. [Copyright &y& Elsevier]