分别采用常规焙烧还原(C)、常规焙烧与常压高频冷等离子体炬还原相结合(PR),以及常压高频冷等离子体炬直接焙烧还原(PC&R)制备了Ni/γ-Al_2O_3催化剂.通过X射线衍射、H_2-程序升温脱附、CO_2-程序升温脱附、N_2吸附-脱附实验、透射电镜和热重分析等方法对催化剂进行了表征.并考察了其CH_4/CO_2重整反应活性.结果表明,催化剂经等离子体处理后低温活性明显增加.在得到相同CH_4和CO_2转化率情况下,PC&R法制备的催化剂与常规催化剂相比,反应所需温度可以降低50℃.PC&R催化剂上Ni分散度提高了100%,Ni粒子粒径降低了70%.达到5 nm,催化剂的抗积炭性能显著增强.所得催化剂较高的低温活性和抗积炭性能得益于常压高频冷等离子体炬对催化剂前驱体还原速率快,处理时间大为缩短,避免了由于长时间高温焙烧和还原所引起的对载体的烧结和金属Ni的团聚.
A series of Ni/γ-Al_2O_3 catalysts were prepared by the conventional calcination and thermal reduction method (C), conventional calcination and atmospheric high frequency cold plasma jet reduction method (PR), and atmospheric high frequency cold plasma jet calcination and reduction method (PC&R). CO_2 reforming of CH_4 was adopted to evaluate the performance of the Ni/y-A1_20_3 catalysts. The results showed that the catalyst prepared by PC&R exhibited better low-temperature activity for CO_2 reforming of CH_4. At the same conversions of CH_4 and CO_2, the reaction temperature of the catalyst prepared by PC&R was 50℃ lower than that of the catalyst by the conventional method. The samples were analyzed by X-ray powder diffraction, temperature-programmed desorption with H_2 and CO_2, N_2 adsorption-desorption, transmission electron microscopy, and thermogravimetric analysis. Compared with the conventional catalyst, the nickel dispersion of the Ni/γ-Al_2O_3 catalyst prepared by PC&R was enhanced by 100%, Ni particle size about 5 nm on catalyst surface was decreased by 70%, and coking resistance was also improved significantly. The excellent low-temperature activity and structure of the catalysts by PC&R were attributed to short treatment time during the plasma process instead of several hours in conventional calcination for decomposing and reducing the catalyst precursor of Ni(NO_3)_2/γ-Al_2O_3, which effectively avoided sintering and plugging.
参考文献
| [1] | Srisiriwat N;Therdthianwong S;Therdthianwong A .[J].International Journal of Hydrogen Energy,2009,34:2224. |
| [2] | Therdthianwong S;Therdthianwong A;Siangchin C;Yongprapat S .[J].International Journal of Hydrogen Energy,2008,33:991. |
| [3] | Pan Y X;Liu C J;Shi P J .[J].Journal of Power Sources,2008,176:46. |
| [4] | Cheng D G;Zhu X L;Ben Y H;He F Cui L Liu C J .[J].Catalysis Today,2006,115:205. |
| [5] | 刘改焕,储伟,龙华丽,戴晓雁,印永祥.用常压高频冷等离子体射流还原Ni/γ-Al2O3催化剂的新方法[J].催化学报,2007(07):582-584. |
| [6] | Liu G H;Li Y L;Chu W;Shi X Y Dai X Y Yin Y X .[J].Catalysis Communications,2008,9:1087. |
| [7] | Vissokov G P;Panayotova M I .[J].Catalysis Today,2002,72:213. |
| [8] | Vissokov G P .[J].Catalysis Today,2004,98:625. |
| [9] | Zea H;Chen C K;Lester K;Phillips A Datye A Fonseca I Phillips J .[J].Catalysis Today,2004,89:237. |
| [10] | Shim H.;Phillips J.;Fonseca IM.;Carabinerio S. .Plasma generation of supported metal catalysts[J].Applied Catalysis, A. General: An International Journal Devoted to Catalytic Science and Its Applications,2002(1/2):41-51. |
| [11] | Zhao Y;Pan Y X;Xie Y B;Liu C J .[J].Catalysis Communications,2008,9:1558. |
| [12] | Liu C J;Yu K;Zhang Y P;Zhu X L He F Eliasson B .[J].Catalysis Communications,2003,4:303. |
| [13] | Zhang Y P;Ma P S;Zhu X L;Liu C J Shen Y T .[J].Catalysis Communications,2004,5:35. |
| [14] | Wang Z J;Zhao Y;Cui L;Du H Yao P Liu C J .[J].Green Chemistry,2007,9:554. |
| [15] | Liu C J;Cheng D G;Zhang Y P;Yu K L Xia Q Wang J G Zhu X L .[J].Catalysis Surveys From Asia,2004,8:111. |
| [16] | 郭芳,储伟,石新雨,张旭.等离子体引入方式对强化制备二氧化碳重整甲烷反应的Ni/γ-Al2O3 催化剂的影响[J].高等学校化学学报,2009(04):746-751. |
| [17] | Zhang Y.;Cao WM.;Luo CR.;Wen XG.;Zhou KL.;Chu W. .A plasma-activated Ni/alpha-Al2O3 catalyst for the conversion of CH4 to syngas[J].Plasma Chemistry and Plasma Processing,2000(1):137-144. |
| [18] | Chen M H;Chu W;Dai X Y;Zhang X W .[J].Catalysis Today,2004,89:201. |
| [19] | Kim S S;Lee H;Na B K;Song H K .[J].Catalysis Today,2004,89:193. |
| [20] | Dittmar A;Kosslick H;Herein D .[J].Catalysis Today,2004,89:169. |
| [21] | Li Z H;Tian S X;Wang H T;Tian H B .[J].Journal of Molecular Catalysis A:Chemical,2004,211:149. |
| [22] | Oukacine L;Gitzhofer F;Abatzoglou N;Gravelle D .Application of the induction plasma to the synthesis of two dimensional steam methane reforming Ni/Al2O3 catalyst[J].Surface & Coatings Technology,2006(5):2046-2053. |
| [23] | Petitpas G;Rollier J D;Darmon A;Gonzalez-Aguilar J,Metkemeijer R,Fulcheri L .[J].International Journal of Hydrogen Energy,2007,32:2848. |
| [24] | Horng R F;Lai M P;Huang H H;Chang Y P .[J].Energy Conversion and Management,2009,50:2632. |
| [25] | Jing Q S;Zheng X M .[J].Energy,2006,31:2184. |
| [26] | 李春林,伏义路,卞国柱.Ni/Ce-Zr-Al-O催化剂的表面碱性和 CO2+CH4重整性能[J].物理化学学报,2003(10):902-906. |
| [27] | Zhang Z L;Verykios X E .[J].Catalysis Today,1994,21:589. |
| [28] | Martinez R;Romero E;Guimon C;Bilbao R .[J].Applied Catalysis A:General,2004,274:139. |
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