Study on Surface Modification of Ni-based Catalysts by Low Temperature Plasma

　　Study on Surface Modification of Ni-based Catalysts by Low Temperature Plasma
　　The utilization of methane has been investigated worldwide for the production of more valuable chemicals in recent years. Partial oxidation of methane (POM) to syngas has attracted much more attention for its special superiorities recently. Among the investigated catalysts, Ni-based catalysts are more promising for their high catalytic activity and low cost. However, the catalysts tested require high temperature activation, and easily lose their activity due to the serious carbon deposit, which limts their further industrial applications. Many scholars try to improve their Alnico magnets catalytic activity and coking-resistant ability by adding lanthanon or alkali metals to the Ni-based catalysts, and have made a small progress but have not solved the problems radically.Based on the previous work, Ni-based catalysts were treated by low temperature plasma under different pressures. It was found that plasma treatment can improve catalytic activity, selectivity and anti-carbon ability. Moreover, plasma treatment can keep the ratio of Ni0/NiO at a certain range which may contributes greatly to the higher catalytic activity and the improved anti-carbon deposition. The reaction initiative temperature was disincreased markedly by adding Pt to Ni-based catalysts or by plasma treatment. It was also found http://www.999magnet.com that effects of different pressure on the catalysts’characters can be seen. When the other conditions are all the same, the pressure is higher, the catalytic activity is higher.It was also found that the different dicharge gas has different effects on the catalysts. The catalytic activity was higher when the discharge gas was mixed gas. The reason may be that after reaction, the Ni0 content on the surface of the catalyst treated by the mixed gas of N2 and O2 or Ar and O2 was higher than that on the surface of the catalyst treated by pure Ar or N2 plasma.