Abstract The Al-promoted Ni-based catalysts were prepared by co-precipitation method using natural clay mineral-palygorskite (Pal) as the support. The physicochemical properties of the catalysts were studied by XRD, BET, H2-TPR, TEM, XPS and Raman spectroscopy. The catalytic performances of the catalysts for CO2 reforming of methane (DRM) were investigated under different parameters including Al content, reaction temperatures, CH4 concentration and gas hourly space velocity (GHSV), and the long-term stability was also evaluated. The results showed that the addition of Al apparently favored the catalytic activity and stability of the catalysts for DRM reactions. The Ni/Pal catalyst with Al content of 8% (Ni8/Al8/Pal) exhibited the best activity for DRM at 700 °C in terms of the CH4 and CO2 conversions, which was related to the high dispersion and small crystal sizes of Ni particles. The variations of CH4 concentration and GHSV showed little effect on the catalytic activity of Ni8/Al8/Pal for CH4 conversion. Long-term stability (140 h) and H2/CO molar ratio of roughly 0.98 can be achieved. The carbon deposition of the spent catalysts indicated that mainly graphite-type carbon deposition was formed on the surface of the catalysts when Al content was lower than 8%; however, most of the carbon deposition was removed over the Ni8/Al8/Pal and Ni8/Al15/Pal catalysts.

中文翻译：

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铝促进的 Ni/坡缕石催化剂对甲烷干重整的高催化性能

摘要 以天然粘土矿物-坡缕石（Pal）为载体，采用共沉淀法制备了铝促进的镍基催化剂。通过XRD、BET、H2-TPR、TEM、XPS和拉曼光谱研究了催化剂的理化性质。在不同参数下研究了甲烷CO2重整(DRM)催化剂的催化性能，包括Al含量、反应温度、CH4浓度和气时空速(GHSV)，并评估了长期稳定性。结果表明，Al的加入明显有利于DRM反应催化剂的催化活性和稳定性。就 CH4 和 CO2 转化率而言，Al 含量为 8% 的 Ni/Pal 催化剂（Ni8/Al8/Pal）在 700 °C 下表现出最佳的 DRM 活性，这与 Ni 颗粒的高分散性和小晶体尺寸有关。CH4浓度和GHSV的变化对Ni8/Al8/Pal的CH4转化催化活性影响不大。可以实现长期稳定性（140 小时）和 H2/CO 摩尔比约为 0.98。废催化剂的积碳表明，当Al含量低于8%时，催化剂表面主要形成石墨型积碳；然而，大部分碳沉积在 Ni8/Al8/Pal 和 Ni8/Al15/Pal 催化剂上被去除。废催化剂的积碳表明，当Al含量低于8%时，催化剂表面主要形成石墨型积碳；然而，大部分碳沉积在 Ni8/Al8/Pal 和 Ni8/Al15/Pal 催化剂上被去除。废催化剂的积碳表明，当Al含量低于8%时，催化剂表面主要形成石墨型积碳；然而，大部分碳沉积在 Ni8/Al8/Pal 和 Ni8/Al15/Pal 催化剂上被去除。