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采用溶液燃烧法制备出PdO/Ce_(1-x)Pd_xO_(2-δ)和PdO/Ce_(1-x)Pd_xO_(2-δ)(Pd O/CPZ)催化剂,通过硝酸处理去除催化剂表面的Pd O物种得到对应的Ce_(1-x)Pd_xO_(2-δ)(CP)和Ce_(1-x)Pd_xO_(2-δ)(CPZ)催化剂。考究四种催化剂(Pd O/CP、Pd O/CPZ、CP、CPZ)对CO和CH_4的氧化活性,并计算得出表面Pd O和Pdn+物种的转化频率(TOF)。结果表明Zr的添加对Pd O催化剂上CO和CH_4的催化氧化活性具有不同的影响。Zr的添加对Pd O/CPZ和CPZ催化剂的CO催化活性具有明显的促进作用,前者归因于PdO/CPZ催化剂表面生成了更小颗粒的Pd O粒子,后者归因于CPZ催化剂中含有更多的氧空位。对于CH_4的催化氧化,Pd~(n+)物种起到关键的作用。由于Zr的掺杂导致Ce O2的晶格中Pd物种的含量减少,致使PdO/CPZ催化剂和CPZ催化剂对CH_4氧化活性的降低。
PdO / Ce_ (1-x) Pd_xO_ (2-δ) and PdO / Ce_ (1-x) Pd_xO_ (2-δ) (Pd O / CPZ) catalysts were prepared by the solution combustion method and treated with nitric acid to remove the (1-x) Pd_xO_ (2-δ) (CP) and Ce_ (1-x) Pd_xO_ (2-δ) The oxidative activities of four catalysts (Pd O / CP, Pd O / CPZ, CP and CPZ) for CO and CH 4 were calculated and the conversion frequency (TOF) of PdO and Pdn + species on the surface was calculated. The results show that the addition of Zr has a different effect on the catalytic oxidation activity of CO and CH_4 on the PdO catalyst. The addition of Zr promoted the CO catalytic activity of PdO / CPZ and CPZ catalysts. The former was attributed to the formation of smaller PdO particles on the surface of PdO / CPZ catalyst, which was attributed to the presence of more More oxygen vacancies. For catalytic oxidation of CH 4, Pd ~ (n +) species play a key role. Due to the doping of Zr, the content of Pd species in the lattice of Ce O2 is reduced, resulting in the decrease of the CH 4 oxidation activity of the PdO / CPZ catalyst and the CPZ catalyst.