甲醇水蒸气重整制氢Cu-Zn-Al尖晶石催化剂的研究

Cu-Zn-Al spinel catalyst for hydrogen production from methanol steam reforming

  • 摘要: 以硝酸铜、硝酸锌、拟薄水铝石和柠檬酸为原料,采用湿式球磨法合成了Cu-Zn-Al三元尖晶石催化剂。通过TG-DTA、XRD、N2物理吸附-脱附、H2-TPR、XPS等表征手段,研究不同Cu/Zn/Al物质的量比对催化剂晶相组成、比表面积、还原性能、表面性质的影响,并通过甲醇水蒸气重整制氢反应(MSR)考察催化剂的缓释催化性能。结果表明,与Cu-Al二元尖晶石相比,Cu-Zn-Al三元尖晶石的结晶度高、比表面积大、更难还原,表现出较好的催化活性,并且其缓释催化行为大不相同。所有催化剂不经预还原处理,即可催化MSR反应,在反应40 h后趋于稳定。其中,Cu∶Zn∶Al = 0.8∶0.2∶2.5(物质的量比)的Cu-Zn-Al催化剂在反应温度265 ℃、水醇比为2、质量空速2.25 h−1的MSR反应中表现出最高的稳定活性。最后结合反应前后催化剂的表征数据,探讨了催化剂活性组分的缓释度,并基于此预测催化剂具有更长的稳定性。

     

    Abstract: The Cu-Zn-Al ternary spinel catalysts were synthesized by the wet ball milling method using copper nitrate, zinc nitrate, pseudoboehmite and citric acid as the raw materials. TG-DTA, XRD, N2 physical adsorption, H2-TPR, XPS and other characterization methods were used to study the effects of different Cu/Zn/Al molar ratios on the crystal phase composition, specific surface area, reduction performance and surface properties of the catalysts, and the catalytic performances of the catalysts were investigated by methanol steam reforming (MSR) for hydrogen production. The results indicate that comparing with the binary Cu-Al spinel, Cu-Zn-Al ternary spinel catalysts have high crystallinity, large surface area and are difficult to be reduced, which show improved catalytic performance and totally different sustained release behavior. The Cu-Zn-Al spinel catalyst with Cu∶Zn∶Al = 0.8∶0.2∶2.5 (molar ratio) exhibited the highest stable catalytic activity in MSR under a reaction temperature of 265 ℃, water/methanol ratio of 2 and mass space velocity of 2.25 h−1. The findings of this work might be served as basic data for further research of such ternary spinel catalysts.

     

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