Nanoscale Co-based catalysts for low-temperature CO oxidation
Nanoscale Co-based catalysts for low-temperature CO oxidation
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DOI：
10.1039/c4cy01147c
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发表时间：
2015-01
影响因子：
5
通讯作者：
Xi Wang;W. Zhong;Yingwei Li
中科院分区：
文献类型：
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作者：
Xi Wang;W. Zhong;Yingwei Li
通过简单热处理含Co金属有机骨架（MOF）的ZIF-67，在不同温度下制备了纳米Co基碳材料，并评价了其对CO低温氧化的催化性能。在600 °C下由ZIF-67热解获得的Co/C-600即使在低至−30 °C的温度下也表现出对CO氧化的高催化活性。CO在Co/C-600催化剂上氧化的计算表观活化能约为22 kJ mol−1。此外，在室温下运行24小时后，CO转化率保持在100%不变，证明了良好的长期稳定性。将水分（H2O含量，~500 ppm）引入进料气体后获得的结果表明，Co/C催化剂耐受潮湿条件，显示出不寻常的温度依赖性催化行为。对催化剂性能的深入研究表明，H2O分子在催化剂微孔中的吸附导致了这种不寻常的催化行为。这一发现支持原位FTIR光谱实验在干燥和潮湿的条件下。此外，通过温和的热处理，Co/C材料对CO氧化的催化活性可以完全恢复。
Nanoscale Co-based carbon materials were prepared by simple thermolysis of a Co-containing metal–organic framework (MOF), ZIF-67, at different temperatures and their catalytic performance for low-temperature CO oxidation was evaluated. Co/C-600, which was obtained from ZIF-67 pyrolysis at 600 °C, exhibited high catalytic activity for CO oxidation even at a temperature as low as −30 °C. The calculated apparent activation energy of CO oxidation over the Co/C-600 catalyst was around 22 kJ mol−1. Moreover, the CO conversion remained unchanged at 100% after 24 h time on stream at room temperature, demonstrating good long-term stability. The results obtained after the introduction of moisture (H2O content, ~500 ppm) into the feed gas showed that the Co/C catalyst was tolerant of wet conditions, showing an unusual temperature-dependent catalytic behavior. Intensive investigation of the catalytic performance led to the conclusion that adsorption of H2O molecules in the micropores of the catalyst caused this unusual catalytic behavior. This finding was supported by in situ FTIR spectroscopic experiments under both dry and wet conditions. Moreover, the catalytic activity of the Co/C material for CO oxidation could be fully recovered by mild heating treatment.