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Nature杂志最近发表了大连化物所在一氧化碳低温催化氧化研究的最新进展(详见Low-temperature oidation of CO catalysed by Co3O4 nanorods, Nature, 2009,458:746-749)。研究人员通过对Co3O4氧化物纳米催化剂粒子尺寸和形貌的精确调控,突破了水汽存在下非贵金属低温一氧化碳催化氧化的难题,在纳米催化基础研究和降低机动车尾气排放和大气环保应用方面具有重要意义。Co3O4 nanorods不仅可以在196 K的温度下实现一氧化碳氧化反应,而且在含水汽的条件下催化剂非常稳定。文章英文摘要t如下:
Low-temperature oxidation of CO, perhaps the most extensively studied reaction in the history of heterogeneous catalysis, is becoming increasingly important in the context of cleaning air and lowering automotive emissions. Hopcalite catalysts (mixture of maganese and copper oxides) were originally developed for purifying air in submarins, but they are not especially active at ambient temperatures and are also deactivated by the presence of moisture. Noble metal catalysts, on the other hand, are water tolerant but usually require temperatures above 100 °C for efficient operation. Gold exhibits high activity at low temperatures and superior stability under moisture, but only when deposited in nanoparticulate form on base transition-metal oxides. The development of active and stable catalysts without noble metals for low-temperature CO oxidation under an ambient atmosphere remains a significant challenge. Here we report that tricobalt tetraoxide nanorods not only catalyse CO oxidation at temperatures as low as –77 °C but also remain stable in a moist stream of normal feed gas. High-resolution transmission electron microscopy demonstrates that the Co3O4 nanorods predominantly expose their {110} planes, favouring the presence of active Co3+ species at the surface. Kinetic analyses reveal that the turnover frequency associated with individual Co3+ sites on the nanorods is similar to that of the conventional nanoparticles of this material, indicating that the significantly higher reaction rate that we have obtained with a nanorod morphology is probably due to the surface richness of active Co3+ sites. These results show the importance of morphology control in the preparation of base transition-metal oxides as highly efficient oxidation catalysts.
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