沉积-沉淀法制备Pd-Cu/凹凸棒土催化剂及其常温潮湿环境下CO催化氧化性能

采用沉积-沉淀法制备Pd-Cu/凹凸棒土(PC/APT)催化剂,以CO氧化为探针反应,在连续流动微反装置上考察其常温潮湿环境下CO催化氧化性能。作为对比,同时采用常规浸渍法制备催化剂。通过N2物理吸附-脱附、XRD、FT-IR和TPR等对催化剂结构和性质进行表征。结果表明,与浸渍法制备的催化剂不同,采用沉积-沉淀法制备的PC/APT催化剂上Cu物种分别以Cu_2Cl(OH)_3和CuO形式存在,其中,Cu_2Cl(OH)_3物种与Pd物种间相互作用较强,催化剂还原性能显著提高,表现出良好的CO催化氧化活性。在空速6 000 h~(-1)、CO体积分数0.5%和水蒸汽体积分数3.3%条件下,采用沉积-沉淀法制备的PC/APT催化剂上CO转化率大于84%的时间不低于160 min。

Preparation of Pd-Cu/APT catalyst via deposition-precipitation method and its behaviors for CO oxidation under room temperature and humid circumstances

Pd-Cu/attapulgite catalyst (PC/APT) was prepared by deposition-precipitation method and its behaviors for CO oxidation under room temperature and humid circumstances was investigated in a fixed-bed continuous flow reactor using CO oxidation under room temperature and humid circumstances as the probe reaction.Pd-Cu/APT catalyst prepared by impregnation method was used as a reference.Structure and properties of the as-synthesized catalysts were characterized by N₂-physisorption,XRD,FT-IR and TPR.The results showed that,unlike the catalyst prepared by impregnation,Cu species existed as Cu₂Cl(OH)₃ and CuO,respectively,on PC/APT catalyst prepared by deposition-precipitation.The strong interaction between Pd species and Cu₂Cl(OH)₃ significantly enhanced reducibility of the catalyst,resulting in excellent catalytic activity for CO oxidation.Under reaction condition of CO 0.5vol%,GHSV 6 000 h^-1,water content 3.3vol% and room temperature,CO conversion over PC/APT catalyst prepared by deposition-precipitation remained at more than 84% for not less than 160 min.