Palacio Ruben, Torres Sebastian, Royer Sébastien, Mamede Anne Sophie, López Diana, Hernández Diana
Química de Recursos Energéticos y Medio Ambiente, Instituto de Química, Facultad de Ciencias Exactas y Naturales, Universidad de Antioquia UdeA, Calle 70 No. 52-21, Medellín, Colombia.
Dalton Trans. 2018 Mar 26;47(13):4572-4582. doi: 10.1039/c7dt04340f.
Ceria supported copper oxide catalysts were produced by a deposition-precipitation method, at a high copper loading (up to >25 wt%). These materials demonstrated excellent properties for glycerol selective conversion to lactic acid, with a conversion reaching up to 87% with a selectivity to lactic acid of 74% (8 h reaction, 220 °C, under N2 pressure). These catalysts also exhibited high stability upon 5 successive reaction cycles. The formation of a crystalline CuO phase was demonstrated in the nanocomposites at a high Cu loading, with elongated shaped particles formed on the cerium oxide surface. Such particles were however, not observed at low Cu loadings. XPS analysis revealed that Cu(ii) was the main Cu species on the fresh catalyst, and that this species was reduced to Cu(i) during the reaction. Complementary characterization over the spent catalyst clearly showed the morphological modifications of the CuO phase, however, did not impact significantly either glycerol conversion or selectivity to lactic acid upon recycling. For instance, apparently, the catalytic activity of CuO largely depends on the Cu(ii) species.
通过沉积沉淀法制备了高铜负载量（高达>25 wt%）的二氧化铈负载氧化铜催化剂。这些材料在甘油选择性转化为乳酸方面表现出优异的性能，在氮气压力下于220°C反应8小时，转化率高达87%，乳酸选择性为74%。这些催化剂在连续5次反应循环后也表现出高稳定性。在高铜负载量的纳米复合材料中证实形成了结晶CuO相，在氧化铈表面形成了细长形状的颗粒。然而，在低铜负载量下未观察到此类颗粒。XPS分析表明，新鲜催化剂上的主要铜物种是Cu(ii)，并且该物种在反应过程中还原为Cu(i)。对失活催化剂的补充表征清楚地显示了CuO相的形态变化，然而，在循环使用时对甘油转化率或乳酸选择性没有显著影响。例如，显然，CuO的催化活性很大程度上取决于Cu(ii)物种。
