异质金属离子掺杂对铈基固溶体催化性能的影响

Effect of heterogeneous metal ion doping on the catalytic properties of cerium-based solid solution

二氧化铈固溶体具有很好的储氧能力,广泛应用于多相催化领域中。但是其高温下易烧结,导致储氧能力显著降低、活性急剧下降,限制了其在高温催化反应中的应用。异质金属离子掺杂能够引起晶格畸变,增加氧负离子流动性,提高铈基固溶体的储放氧能力,是提高铈基固溶体催化性能最有效的方法。本文综述了过渡金属、贵金属、稀土金属、碱土金属和碱金属等异质金属离子掺杂改性的铈基固溶体在催化领域中的国内外研究进展。从掺杂元素的理化特性出发,总结了异质金属离子对铈基固溶体的储放氧能力、活性组分分散状态、催化剂活性和稳定性等影响规律及作用机制。综述指出铈基固溶体掺杂改性的研究方向为进一步提升异质金属离子在二氧化铈晶胞中的溶解度,注重研究并提高催化剂的抗水性能和耐毒性及催化剂的寿命等研究。

Cerium dioxide has been widely used in the field of heterogeneous catalysis because of its relatively high oxygen storage capacity. The agglomeration, however, restricts its applications because there is a sharp decrease in oxygen storage capacity and reactivity during catalytic process at high temperatures. The doping of heterogeneous metal ions is the most effective way to improve the catalytic performance of cerium-based solid solution, which can cause lattice distortion, increase the oxygen anion mobility and improve the oxygen storage capacity of the cerium-based solid solution. In this paper, the research progress of ion-doped cerium-based solid solution in the field of catalysis was reviewed. The foreign ions can be transition metals, precious metals, rare earth metals, alkaline earth metals and alkali metals. Based on the physicochemical properties of the dopant elements, the effects of heterogeneous metal ions on the oxygen storage capacity, the dispersion of active components, the activity and stability of the cerium-based solid solution were summarized. The review points out that further research should be more focused on increasing the solubility of heterogeneous metal ions in cerium dioxide crystal lattice and enhancing the stability in cases of high humidity, high toxicity and long term.