In order to reach the limits of CO₂ emissions set by Kyoto protocol, the use of biofuels is gaining momentum. However, the biofuels contains alkali and alkaline earth metals (Na, K and Ca) and phosphorus (P) species, which could decrease the efficiency of the after-treatment system. The main aim of this study is to increase the knowledge of the effect of impurities contain on biofuel on the catalytic activity of the diesel oxidation catalysts (DOCs). Both reference (PtPd/CeZrO₂/La-Al₂O₃) and modified catalysts were synthesized, characterized by several techniques and tested, concerning their physico-chemical, redox and catalytic properties. Based on the characterization results, the catalyst crystalline structure did not change after the impurities incorporation, however, the specific surface area was decreased in all cases. NO adsorption strength was increased due to the low electronegativity of Na, K and Ca species, according to H₂-TPR and NO-TPD analyses. XPS analysis confirmed the formation of cerium phosphate, which can stabilize the Ce³⁺ oxidation state related to its higher Ce³⁺/Ce⁴⁺ ratio, diminishing the catalytic redox activity. The physico-chemical and redox properties modifications after Na, K and Ca impurities addition diminished the CO and NO removal, however, the C₃H₆ conversion was improved. Besides, both CO and C₃H₆ oxidation were enhanced, while the NO to NO₂ conversion decreased in presence of P species.

为了达到《京都议定书》设定的CO ₂排放极限，生物燃料的使用正日益兴起。但是，生物燃料包含碱金属和碱土金属（Na，K和Ca）和磷（P），这可能会降低后处理系统的效率。这项研究的主要目的是增加对生物燃料中所含杂质对柴油机氧化催化剂（DOC）催化活性影响的认识。双方参考（PtPd / CeZrO ₂ / La-Al ₂ O ₃）和改性的催化剂被合成，通过几种技术进行表征并经过测试，涉及到它们的物理化学，氧化还原和催化性能。根据该表征结果，杂质掺入后催化剂的晶体结构没有改变，但是在所有情况下比表面积均降低。根据H ₂ -TPR和NO-TPD分析，由于Na，K和Ca物种的低电负性，NO吸附强度得以提高。XPS分析证实了磷酸铈的形成，该磷酸铈可以稳定与其较高的Ce ³⁺ / Ce ⁴⁺有关的Ce ³⁺氧化态比例降低催化氧化还原活性。添加Na，K和Ca杂质后，理化性质和氧化还原性质的改变减少了CO和NO的去除，但是C ₃ H _6的转化率得到了改善。此外，在P物种存在下，CO和C ₃ H _6的氧化均增强，而NO转化为NO _2的转化减少。