School of Safety Engineering and Technology,Heilongjiang University of Science and Technology,Harbin　 150022,China

低温等离子体技术在催化剂改性方面表现出良好的应用前景。为此,利用大气压介质阻挡放电对CuO/Al2O3催化剂进行处理,研究了等离子体处理顺序对CuO/Al2O3催化乏风瓦斯燃烧性能的影响。结果表明,先焙烧后等离子体处理能提高催化剂的活性。催化剂的SEM,BET,XRD,XPS表征显示,焙烧前进行等离子体处理的催化剂较焙烧后进行等离子体处理的催化剂CuO晶粒尺寸增大了8倍,从而导致催化剂表面金属分散性明显降低,进而影响了催化效果。采用先等离子体处理方式制备的催化剂CuO颗粒团聚变大的原因为等离子体处理减弱了Cu与载体Al2O3之间的作用力,致使在后续焙烧过程中催化剂表面CuO颗粒变大。同时,焙烧后等离子体处理与焙烧前等离子体处理制得的催化剂比较,比表面积和孔容增大,而孔径变小。等离子体的处理顺序未改变催化剂中铜的化学价态。

Low temperature plasma as a technology for surface modification of materials has a good application prospect in catalyst modification field. The CuO / Al2 O3 catalyst was treated by O2 plasma in a dielectric barrier discharge (DBD) reactor. The effect of plasma treatment sequence on the performance of CuO / Al2 O3 catalyst in the combustion of methane in ventilation air was investigated using catalytic combustion experiment and SEM,BET,XRD,and XPS characterizations. The results show that the modification of catalyst after calcination is preferred because it could im- prove the catalytic activity of CuO / Al2 O3 catalyst for the combustion of methane in ventilation air. The CuO grain size of the catalyst prepared by plasma treatment before calcinations is eight times larger than that of the catalyst obtained after the calcinations. As a result,the CuO dispersion of the catalyst surface is significantly reduced,which affects the catalytic effect. The reason for the larger agglomeration of the CuO particles prepared by the first plasma treatment is that the plasma treatment weakens the force between the Cu and the support Al2 O3 and increases the size of the CuO particles during the subsequent calcination. At the same time,the specific surface area and pore volume increase with the post-plasma treatment compared with the first plas-ma-treated catalyst,while the pore size decreases. The sequence of plasma treatment do not change the chemical valence of copper in the catalyst.

ZHU Lihua,BI Fangqiang,LI Fan,et al. Effect of plasma treatment sequence on performance of CuO / Al2 O3 catalyst in combustion of methane in ventilation air [ J]. Journal of China Coal Society,2018,43 ( 12 ):3419 - 3424.