使用不同浓度(0～67%)的硝酸对活性炭载体进行预处理,以H2PdCl4为前驱体,用浸渍法制备理论负载量为5%的Pd/C催化剂. 浸渍过程中的吸附实验表明, Pd前驱体的平衡吸附量随预处理硝酸浓度的增加而逐渐减小,尤其是浓硝酸预处理的活性炭载体,其上仅有62.54%的P d前驱体吸附,而37.46%的Pd前驱体仍在水浆液中. 分析发现, Pd前驱体的平衡吸附量主要取决于活性炭的零电荷点,表面电荷模型能较好地描述Pd前驱体的吸附规律. 当使用浓度≤5 %的硝酸进行预处理时, Pd的粒径随硝酸浓度的增加而减小;当硝酸浓度继续增加时, Pd粒径急剧增大. Pd前驱体的平衡吸附量与Pd粒径的大小无直接关系,而Pd前驱体在活性炭表面上吸附物种及数量的不同也对Pd粒径的大小产生影响. 活性炭表面基团的增加抑制了PdCly-x吸附物种的生成. 当使用≤5%的硝酸处理活性炭时, Pd 前驱体的吸附形态主要为PdCly-x和Pd0;当硝酸浓度>5%时,没有检测到 PdCly-x的存在.
参考文献
| [1] | Doesburg E B M;de Jong K P;van Hooff J H C .[J].Studies in Surface Science and Catalysis,1999,123:433. |
| [2] | Geus J W;van Veen J A R .[J].Studies in Surface Science and Catalysis,1999,123:459. |
| [3] | Rodriguez-Reinoso F. .The role of carbon materials in heterogeneous catalysis[J].Carbon: An International Journal Sponsored by the American Carbon Society,1998(3):159-175. |
| [4] | Auer E;Freund A;Pietsch J;Tacke T .[J].Applied Catalysis A:General,1998,173(02):259. |
| [5] | Toebes M L;van Dillen J A;de Jong K P .[J].Journal of Molecular Catalysls A:Chemical,2001,173(1-2):75. |
| [6] | Fraga M A;Jordao E;Mendes M J;Freitas M M A Faria J L Figueiredo J L .[J].Journal of Catalysis,2002,209(02):355. |
| [7] | Boehm H P .[J].Advances in Catalysis,1966,16:179. |
| [8] | Fanning P E;Vannice M A .[J].Carbon,1993,31(05):721. |
| [9] | Li, JY;Ma, L;Li, XN;Lu, CS;Liu, HZ .Effect of nitric acid, pretreatment on the properties of activated carbon and supported palladium catalysts[J].Industrial & Engineering Chemistry Research,2005(15):5478-5482. |
| [10] | Donnet J B .[J].Carbon,1968,6(02):161. |
| [11] | Figueiredo J L;Pereira M F R;Freitas M M A;Orfao J J M .[J].Carbon,1999,37(09):1379. |
| [12] | Boehm H P .[J].CARBON,1994,32(05):759. |
| [13] | Boehm H P;Diehl E;Neck W;Sappok R .[J].Angewandte Chemie International Edition,1964,3(10):669. |
| [14] | Román-Martínez M C;Cazorla-Amorós C;Linares-Solano A;De Lecea C S M Yamashita H Anpo M .[J].Carbon,1995,33(01):3. |
| [15] | Lin S D;Hsu Y H;Jen P H;Lee J F .[J].Journal of Molecular Catalysls A:Chemical,2005,238(1-2):88. |
| [16] | Prado-Burguete P;Linares-Solano A;Rodriguez-Reinoso F;De Lecea C S M .[J].Journal of Catalysis,1989,115(01):98. |
| [17] | van Dam H E;van Bekkum H .[J].Journal of Catalysis,1991,131(02):335. |
| [18] | Krishnankutty N.;Vannice MA. .THE EFFECT OF PRETREATMENT ON PD/C CATALYSTS .1. ADSORPTION AND ABSORPTION PROPERTIES [Review][J].Journal of Catalysis,1995(2):312-326. |
| [19] | Noh J S;Schwarz J A .[J].Carbon,1990,28(05):675. |
| [20] | Cerveny L .[J].Chemical Engineering Communications,1989,83(01):31. |
| [21] | Falconer J L;Schwarz J A .[J].Catalysis Review:Science and Engineering,1983,25(02):141. |
| [22] | Krishnankutty N.;Vannice MA. .THE EFFECT OF PRETREATMENT ON PD/C CATALYSTS .2. CATALYTIC BEHAVIOR[J].Journal of Catalysis,1995(2):327-335. |
| [23] | Zhuang Q L;Kyotany T;Tomita A .[J].CARBON,1994,32(03):539. |
| [24] | Farkas G;Hegedus L;Tungler A;Mathe T Figueiredo J L Freitas M .[J].Journal of Molecular Catalysls A:Chemical,2000,153(1-2):215. |
| [25] | Otake Y;Jenkins R G .[J].Carbon,1993,31(01):109. |
| [26] | Zielke U.;Hoffman WP.;Huttinger KJ. .SURFACE-OXIDIZED CARBON FIBERS .1. SURFACE STRUCTURE AND CHEMISTRY[J].Carbon: An International Journal Sponsored by the American Carbon Society,1996(8):983-998. |
| [27] | Czárán E;Finster J;Schnabel K H .[J].Zeitschrift Fur Anorganische Und Allgemeine Chemie,1978,443:175. |
| [28] | Mojet B L;Hoogenraad M S;van Dillen A J;Geus J W,Koningsberger D C .[J].Journal of the Chemical Society,Faraday Transactions,1997,93(24):4371. |
上一张
下一张
上一张
下一张
计量
- 下载量()
- 访问量()
文章评分
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%