【作者】 王成；

【导师】 李新刚；

【作者基本信息】 天津大学 ， 工业催化， 2017， 硕士

【摘要】 一氧化碳优先氧化法（CO PROX）是最有效、最有发展前景的富氢气氛中CO消除方法。本文采用四种方法制备了CeO₂载体,对这些载体负载CuO催化剂进行了详细表征,考察了这些CuO/CeO₂催化剂的CO PROX性能。制备了超细Ce（OH）₃纳米线,在250℃条件下焙烧,得到具有高表面缺陷和高比表面积的CeO₂载体（Ce250）。Ce250负载10%CuO后在不同温度下焙烧,得到一系列CuCeX催化剂。通过TEM、BET、XRD、UV-Raman、H₂-TPR、XPS和Cu K边XAFS技术对催化剂进行表征。相对于高温条件下焙烧Ce（OH）₃纳米线得到的载体和普通沉淀法制备的载体,Ce250具有最高的表面缺陷位,在焙烧过程中有利于增强CuO与CeO₂之间的相互作用。而CuO与CeO₂相互作用是决定催化剂活性的主要因素,随着催化剂焙烧温度的升高,CuO与CeO₂之间的相互作用不断增强,但由于500℃焙烧的催化剂（CuCe500）比表面积远高于600℃焙烧的样品,所以表观活性最高。对应的50%和100%CO转化温度为71和100℃,CO完全转化温度窗口为100-161℃。本文采用草酸盐热分解法、纳米线断裂法、尿素热分解法和普通沉淀法制备了四种不同的CeO₂载体。这些载体负载10%的CuO制备了CuO/CeO₂催化剂,并用于CO PROX研究。结果表明,采用草酸盐热分解法制备的催化剂由于具有最强的CuO与CeO₂相互作用和较高的比表面,所以催化剂活性最高,对应的CO 100%完全转化温度为98℃,完全转化温度窗口为98-160℃。采用草酸盐热分解法制备了CeO₂载体,负载CuO得到CuO/CeO₂催化剂,用于CO PROX研究。采用TEM、HRTEM、BET、XRD、UV-Raman、H₂-TPR及XPS技术对催化剂进行表征。对于所有的催化剂,在负载CuO后会形成CuCe固溶体,能够产生更多表面氧空位和表面Ce³⁺。由于CuO和CeO₂之间的相互作用,从而生成更多的表面Cu⁺,由于表面Cu⁺为催化剂的活性物种,从而提高催化剂活性。CuO负载量为10%时,具有最强的CuO和CeO₂相互作用和最丰富的表面Ce³⁺含量,所以催化剂活性最好,对应的CO完全转化温度点为98℃,完全转化窗口为98-160℃。更多还原

【Abstract】 The CO preferential oxidation（CO PROX）is the most effective and promising method for the remove of CO in the H₂-rich stream.In this work,we adopted four methods to prepare CeO₂ support.The CuO/CeO₂ catalysts prepared by using these CeO₂ as supports were detailedly characterized,and their catalytic performance for CO PROX was investigated.We prepared the superfine Ce（OH）₃ nanowires and calcined them at 250℃ to get the CeO₂ support（Ce250）with large amount of surface defects and high specific surface area.Ce250 was supported with 10%CuO and then were calcined at different temperature to get a series of CuCeX catalysts.The catalytic performance for CO PROX over the CuCeX catalysts was tested.The CuCeX catalysts were characterized with BET,XRD,UV-Raman,H₂-TPR,XPS and Cu K-edge XAFS techniques.Compared with the support prepared by calcining the superfine Ce（OH）₃ nanowires at higher temperature or the support prepared by precipitation method,the Ce250 shows much more surface defects,which is beneficial for the strength of the interaction between CuO and CeO₂.The interaction between CuO and CeO₂ is the main factor to affect catalytic performance for CO PROX and is strengthed with the increase of the calcination temperature,so the intrinsic activity of the catalysts is increased with the increase of the calcination temperature.However,as the specific surface area of CuCe500 is much higher than CuCe600,the apparent activity of CuCe500 is the highest with the lowest 50%and 100%CO convention temperature at 71 and 100℃,respectively,and the temperature window for CO full convention is 100-161℃.The CeO₂ supports were prepared by oxalate thermal decomposition,nanowire breaking method,urea thermal decomposition method and precipitation method,respectively.After loaded with 10%CuO,the catalysts were used for the CO PROX reactions.The catalysts were characterized by BET,XRD and H₂-TPR techniques.The results show that the catalysts prepared by oxalate thermal decomposition–impregnation method has the strongest interaction between CuO and CeO₂ and high specific surface area,so has the highest CO PROX activity with the CO full convention temperature of 98℃ and the full convention window of 98-160℃.A series of CuO/CeO₂ catalysts with different CuO loading were prepared by oxalate thermal decomposition–impregnation method and used for the CO PROX reaction.The catalysts were characterized by TEM,HRTEM,BET,XRD,UV-Raman,H₂-TPR and XPS techniques.For all the catalysts,CuCe solid solution may be formed during the preparation process,which would introduce more surface oxygen vacancy and Ce³⁺.As the interaction between CuO and Ce O₂,Many active sites of Cu⁺would be formed due to the interaction between CuO and CeO₂,and it improves the catalysts activity.As the 10%Cu Ce catalyst has the strongest CuCe interaction and the most amount of surface Ce³⁺content,it has the higest CO PROX activity with the CO full convention temperature at 98℃,and the window temperature for CO full convension is 98-160℃.更多还原