Effects of zirconia phase on the synthesis of methanol over zirconia-supported copper
Effects of zirconia phase on the synthesis of methanol over zirconia-supported copper
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DOI：
10.1023/a:1015326726898
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发表时间：
2002-01-01
影响因子：
2.8
通讯作者：
Bell, AT
中科院分区：
文献类型：
--
作者：
Jung, KT;Bell, AT
研究了在CO/H_2和CO_2/H_2合成甲醇反应中，氧化锆物相和铜对氧化锆比表面积的影响。为了考察氧化锆相的影响，在四方(t-)和单斜(m-)氧化锆上制备了一对Cu/ZrO2催化剂。两种催化剂的氧化锆比表面积和铜分散度基本相同。在548K、0.65 Mpa、H-2/COX=3(x=1，2)条件下，以m-ZrO2为载体制备的催化剂对CO2/H-2合成甲醇的催化活性是t-ZrO2催化剂的4.5倍，是以CO/H-2为原料的催化剂的7.5倍。增加m-ZrO2的比表面积和比表面积进一步提高了甲醇合成活性。原位红外光谱和瞬变响应实验表明，在Cu/m-ZrO2催化剂上，CO2/H-2合成甲醇的高速率完全是由于活性中间体浓度较高所致。相比之下，CO/H-2合成甲醇的速率较高，这既是由于表面中间体浓度较高，也是因为它们在Cu/ZIO(2)上的转化动力学较快。
A study has been conducted to identify the influence of zirconia phase and copper to zirconia surface area on the activity of Cu/ZrO2 catalysts for the synthesis of methanol from either CO/H-2 or CO2/H-2,. To determine the effects of zirconia phase, a pair of Cu/ZrO2, catalysts was prepared on tetragonal (t-) and monoclinic (m-) zirconia. The zirconia surface area and the Cu dispersion were essentially identical for these two catalysts. At 548 K, 0.65 MPa, and H-2/COx = 3 (x = 1, 2), the catalyst prepared on m-ZrO2 was 4.5 times more active for methanol synthesis from CO2/H-2 than that prepared on t-ZrO2, and 7.5 times more active when CO/H-2 was used as the feed. Increasing the surface area of m-ZrO2 and the ratio of Cu to ZrO2 surface areas further increased the methanol synthesis activity. In situ infrared spectroscopy and transient-response experiments indicate that the higher rate of methanol synthesis from CO2/H-2 over Cu/m-ZrO2 is due solely to the higher concentration of active intermediates. By contrast, the higher rate of methanol synthesis from CO/H-2, is due to both a higher concentration of surface intermediates and the more rapid dynamics of their transformation over Cu/ZiO(2).