A novel series of nickel (Ni) loaded on Fibrous Mesoporous Silica Nanoparticles (CHE-SM) support with varying Ni contents (=1–30 wt%) were synthesized, denoted as Ni/CHE-SM and then investigated for carbon dioxide (CO) methanation. The catalysts underwent comprehensive characterization using XRD, N adsorption-desorption, FESEM, FTIR-KBr, H-TPR, and CO-TPD techniques. The XRD and FESEM analyses confirmed the structural integrity of CHE-SM, irrespective of the Ni loading. However, the size of the nanocrystalline NiO particles appeared to be influenced by the Ni loading. Notably, 20Ni/CHE-SM exhibited the highest CO conversion of 92% at 350 °C, demonstrating its potential for low-temperature activation. H-TPR and CO-TPD results revealed favorable NiO reduction at lower temperatures, indicating medium-strength basicity that facilitated efficient CO and H adsorption and activation. Consequently, 20Ni/CHE-SM exhibited superior catalytic performance compared to other catalysts, with lower activation energy (61.5 kJ/mol). Kinetic studies focusing on 20Ni/CHE-SM indicated a molecular adsorption mechanism of CO and H on a single site after evaluation using four Langmuir-Hinshelwood models. This result was attributed to the high amount of medium strength basicity possessed by the 20Ni/CHE-SM catalyst which provided an abundance of adsorption sites, resulting in greater fractional coverage of reactants and enhancing the CH formation rate.

中文翻译：

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纤维介孔二氧化硅纳米颗粒负载镍 (CHE-SM) 上 CO2 甲烷化的动力学探索


合成了一系列负载在纤维状介孔二氧化硅纳米颗粒 (CHE-SM) 载体上的新型镍 (Ni)，其镍含量不同 (=1–30wt%)，表示为 Ni/CHE-SM，然后研究了二氧化碳 (CO ）甲烷化。使用 XRD、N2 吸附-解吸、FESEM、FTIR-KBr、H-TPR 和 CO-TPD 技术对催化剂进行了全面表征。 XRD 和 FESEM 分析证实了 CHE-SM 的结构完整性，无论 Ni 负载量如何。然而，纳米晶 NiO 颗粒的尺寸似乎受到 Ni 负载量的影响。值得注意的是，20Ni/CHE-SM 在 350 °C 时表现出最高的 CO 转化率，达到 92%，展示了其低温活化的潜力。 H-TPR 和 CO-TPD 结果显示，在较低温度下，NiO 发生良好的还原，表明中等强度的碱性有利于 CO 和 H 的有效吸附和活化。因此，与其他催化剂相比，20Ni/CHE-SM表现出优异的催化性能，且活化能较低（61.5kJ/mol）。在使用四个 Langmuir-Hinshelwood 模型进行评估后，针对 20Ni/CHE-SM 的动力学研究表明了 CO 和 H 在单个位点上的分子吸附机制。这一结果归因于20Ni/CHE-SM催化剂具有大量的中等强度碱性，提供了丰富的吸附位点，导致反应物的覆盖分数更大并提高了CH的形成速率。