Palladium-gold bimetallic nanoparticles deposited on the graphene oxide(GO)doped Zn-Al layered double hydroxide(PdAu/Zn-Al LDHs/GO)were synthesized through the ion exchange-reduction method. The as-prepared supported palladium-gold bimetallic catalysts were characterized by XRD and TEM. The bimetallic nanoparticles loaded by the GO doped Zn-Al LDHs as the carrier is uniform and the particle size is about 2nm. The catalytic activities of as-prepared catalysts were evaluated by using oxidation of benzyl alcohol to benzaldehyde as the model reaction. The effects of carriers and ratio of Pd/Au on the catalytic properties were investigated. The catalytic results showed that the LDHs/GO was the best among the used carriers. As the increase of ratio of Pd/Au,the activity of supported catalyst increased at first,and then decreased,whereas the selectivity of benzaldehyde decreased. With the ratio of Pd/Au being 1:1 at 80℃,the performances of Pd1Au1/Zn-Al LDHs/GO is the best. The catalytic activity increased as the increase of temperature,but the selectivity of benzaldehyde decreased. Under promotion of Pd1Au1/Zn-Al LDHs/GO at 80℃ for 8h,the conversion of benzyl alcohol and selectivity of benzaldehyde was 96％ and 93％,respectively. The catalyst of Pd1Au1/Zn-Al LDHs/GO still maintained excellent catalytic performance after four cycles.%采用离子交换-还原法制备了氧化石墨烯(GO)掺杂锌铝类水滑石负载钯金双金属纳米颗粒的催化剂(PdAu/Zn-AlLDHs/GO),通过XRD、TEM表征了催化剂的结构,以GO掺杂锌铝类水滑石为载体负载钯金纳米颗粒粒径小(约2nm)且分散均匀.以苯甲醇空气氧化形成苯甲醛的反应为模型,评价催化剂的催化性能,探讨了载体及钯、金比例对催化反应的影响.催化结果表明,氧化石墨烯掺杂的锌铝类水滑石是考察载体中最好的钯、金催化剂的载体,随着钯金比的增加催化剂的催化活性先增加后降低,生成苯甲醛的选择性下降,当钯金比例为1:1时,催化剂(Pd1Au1/Zn-AlLDHs/GO)的综合催化性能最好,催化活性随反应温度的升高而升高,但选择性随温度的升高而下降.在Pd1Au1/Zn-AlLDHs/GO催化下,80℃反应8h后苯甲醇的转化率可达96％,苯甲醛的选择性为93％,催化剂循环使用4次后仍保持较好的催化性能.
展开▼
