Yue-ping Zhang

Plasma methane conversion in the presence of carbon dioxide using dielectric-barrier discharges

Abstract Methane conversion in the presence of carbon dioxide was investigated under the conditions of dielectric-barrier discharge plasmas. Different from the previous investigations, the grounded electrode is covered by the dielectric material (quartz) in the present reactor design. The product contains gaseous hydrocarbons, syngas and oxygenates. No liquid hydrocarbons can be detected with the present reactor design. The oxygenates produced includes acetic acid, propanoic acid, ethanol and methanol. There exists an optimum feed ratio of CH 4 /CO 2 to make the maximum selectivity of the objective oxygenate. The highest selectivity of acetic acid was 5.2% achieved at CH 4 and CO 2 conversions of 64.3% and 43.1%, respectively.

Starch-Enhanced Synthesis of Oxygenates from Methane and Carbon Dioxide Using Dielectric-Barrier Discharges

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 selectivity of oxygenates. Oxygenates produced include primarily formaldehyde, methanol, ethanol, formic acid, and acetic acid. The total selectivity is about 10–40% with conversion of methane and carbon dioxide of about 20%. Lower methane feed concentration favors the production of oxygenates, and higher feed flow rate leads to higher selectivity of oxygenates in the presence of starch.

A DFT study of synthesis of acetic acid from methane and carbon dioxide

Abstract We have previously reported an experimental investigation on synthesis of acetic acid directly from CH 4 and CO 2 via dielectric-barrier discharge. In this work, a DFT study was conducted using three hybrid DFT methods in order to understand the mechanism of such direct synthesis. It suggests that the synthesis is via two pathways with CO 2 − and CO as key intermediates. The energy requirement with CO 2 − pathway is much less than that with CO. The methyl radical formation and the dissociation of CO 2 are two limiting steps for the synthesis of acetic acid directly from CH 4 and CO 2 .

Remarkable improvement in the activity and stability of Pd/HZSM-5 catalyst for methane combustion

Abstract 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.

Effect of Catalyst Preparation on Carbon Nanotube Growth

A highly dispersed Ni–Fe/Al2O3 catalyst was prepared by glow discharge plasma treatment followed by thermal calcinations. With this plasma prepared catalyst, carbon nanotubes encapsulated with metal particle or filled with nickel nano-wire were produced. This is very different from the conventional catalyst, with which the normal multi-wall carbon nanotubes or nano-capsule chains were synthesized. The plasma preparation leads to a significant change in the interaction between metal and the support.