泡沫镍负载CeO_(2)改性CuO催化剂的碳烟燃烧性能研究

Performance of soot combustion over CeO_(2) modified CuO catalysts supported on nickel foams

通过在泡沫镍基底上预沉积CeO_(2)晶核,采用水热法成功合成出泡沫镍负载CeO_(2)改性CuO催化剂(xCeO_(2)-CuO/NF),同未加入CeO_(2)的催化剂(CuO/NF)相比,其碳烟氧化活性显著提高。随着催化剂中CeO_(2)含量的增加,Ce/Cu质量比不断增大直至趋于平稳,催化剂的催化活性随之提高直至基本不变。其中,6.5CeO_(2)-CuO/NF的催化活性最好,T_(50)(383℃)最低,比CuO/NF催化剂低32℃。研究结果表明,预沉积CeO_(2)晶核一方面可促进CuO微纳结构的生长,提高碳烟颗粒与催化剂活性位点的接触效率;另一方面,xCeO_(2)-CuO/NF中形成的Cu_(x)Ce_(1-x)O固溶体增强了铜铈之间的相互作用,通过Ce^(3+)/Ce^(4+)和Cu^(2+)/Cu^(+)之间氧化还原耦合循环促使活性氧物种的生成,并提升了其本征活性,从而极大地提高了其催化碳烟氧化的能力。

CeO_(2)-modified CuO catalyst(xCeO_(2)-CuO/NF)was successfully synthesized by hydrothermal method through pre-deposition of CeO_(2) crystal nuclei on nickel foam substrate.The soot oxidation activity of xCeO_(2)-CuO/NF was significantly higher than that of the catalyst without addition of CeO_(2)(CuO/NF).With the increase of CeO_(2) content,the Ce/Cu mass ratio and the intrinsic catalytic activity of the catalyst gradually increased,and finally both of them reached stable.Among them,the catalytic activity of 6.5CeO_(2)-CuO/NF was the best with the lowest T_(50)(383℃),which was 32℃lower than that of the CuO/NF catalyst.The results indicate that the predeposition of CeO_(2) crystal nuclei can promote the growth of CuO into a nanostructure,which improves the contact efficiency between soot particles and active sites of the catalyst,on the other hand,the formation of Cu_(x)Ce_(1-x)O solid solution on xCeO_(2)-CuO/NF enhances the interaction between Ce and Cu cations.The interaction generates a redox coupling cycle between Ce^(3+)/Ce^(4+)and Cu^(2+)/Cu^(+),prompting the generation and intrinsic activity of active oxygen species.All of these merits greatly improve the catalytic performance of soot oxidation over our as-synthesized catalysts.