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以共沉淀法制得的Co_3O_4为载体,采用两步法负载Au和Cu制得了一系列Au-Cu/Co_3O_4双金属催化剂,考察了Au-Cu/Co_3O_4双金属催化剂完全催化氧化乙烯的性能,并通过X射线衍射(XRD)、高分辨透射电镜(HRTEM)、H_2程序升温还原(H_2-TPR)和O_2程序升温脱附(O_2-TPD)对催化剂进行了表征.活性测试结果表明:负载型Au-Cu/Co_3O_4双金属催化剂的催化性能优于单一金属催化剂Au/Co_3O_4,并且在Au负载量为4%(w,质量分数)时,与AuCu/Co_3O_4和Au_3Cu/Co_3O_4催化剂相比,AuCu_3/Co_3O_4催化剂的催化活性较好,0℃时可催化转化15.3%的乙烯为CO_2和H_2O,120℃时100%催化转化乙烯.XRD和HRTEM表明,AuCu_3/Co_3O_4催化剂中有Au-Cu合金相的生成,而Au_3Cu/Co_3O_4催化剂中Cu主要以氧化物的形式存在.Au和Cu之间产生相互作用,使活性相金属的粒径降低.H_2-TPR和O_2-TPD分析结果表明,AuCu_3/Co_3O_4催化剂具有较强的低温可还原能力和可提供的大量表面活性吸附氧物种,促进了乙烯的完全催化氧化.
A series of Au-Cu / Co_3O_4 bimetallic catalysts were prepared by co-precipitation method using Co_3O_4 as support. The Au-Cu / Co_3O_4 bimetallic catalysts were supported by two-step method. The catalysts were characterized by X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), H 2 temperature programmed reduction (H 2 -TPR) and O 2 -TPD.The results of the activity test showed that the supported Au- The catalytic performance of Cu / Co 3 O 4 bimetallic catalyst is better than that of single metal catalyst Au / Co 3 O 4. Compared with AuCu / Co 3 O 4 and Au 3 Cu / Co 3 O 4 catalysts, AuCu 3 / Co 3 O 4 catalyst , Catalytic conversion of 15.3% of ethylene to CO_2 and H_2O at 0 ℃ and 100% of catalytic conversion of ethylene at 120 ℃, XRD and HRTEM show that Au-Cu alloy phase is formed in AuCu_3 / Co_3O_4 catalyst, while Cu in Au_3Cu / Co_3O_4 catalyst exists mainly in the form of oxides, and the interaction between Au and Cu leads to the decrease of the particle size of the active phase metal.The results of H_2-TPR and O_2-TPD show that the AuCu_3 / Co_3O_4 catalyst has stronger The low temperature reducibility and can provide large Surfactants adsorbed oxygen species promote the catalytic oxidation of ethylene completely.