Grabchenko Maria V, Dorofeeva Natalia V, Svetlichnyi Valery A, Larichev Yurii V, La Parola Valeria, Liotta Leonarda Francesca, Kulinich Sergei A, Vodyankina Olga V
Laboratory of Catalytic Research, Tomsk State University, 634050 Tomsk, Russia.
Laboratory of Advanced Materials and Technology, Siberian Physical Technical Institute, Tomsk State University, 634050 Tomsk, Russia.
Nanomaterials (Basel). 2023 Sep 26;13(19):2641. doi: 10.3390/nano13192641.
Dry reforming of methane with ratio CH/CO = 1 is studied using supported Ni catalysts on SBA-15 modified by CeMnO mixed oxides with different Ce/Mn ratios (0.25, 1 and 9). The obtained samples are characterized by wide-angle XRD, SAXS, N sorption, TPR-H, TEM, UV-vis and Raman spectroscopies. The SBA-15 modification with CeMnO decreases the sizes of NiO nanoparticles and enhances the NiO-support interaction. When Ce/Mn = 9, the NiO forms small particles on the surface of large CeO particles and/or interacts with CeO, forming mixed phases. The best catalytic performance (at 650 °C, CH and CO conversions are 51 and 69%, respectively) is achieved over the Ni/CeMnO/SBA-15 (9:1) catalyst. The peculiar CeMnO composition (Ce/Mn = 9) also improves the catalyst stability: In a 24 h stability test, the CH conversion decreases by 18 rel.% as compared to a 30 rel.% decrease for unmodified catalyst. The enhanced catalytic stability of Ni/CeMnO/SBA-15 (9:1) is attributed to the high concentration of reactive peroxo (O) and superoxo (O) species that significantly lower the amount of coke in comparison with Ni-SBA-15 unmodified catalyst (weight loss of 2.7% vs. 42.2%). Ni-SBA-15 modified with equimolar Ce/Mn ratio or Mn excess is less performing. Ni/CeMnO/SBA-15 (1:4) with the highest content of manganese shows the minimum conversions of reagents in the entire temperature range (X(CO) = 4-36%, X(CH) = 8-58%). This finding is possibly attributed to the presence of manganese oxide, which decorates the Ni particles due to its redistribution at the preparation stage.
研究了使用不同Ce/Mn比（0.25、1和9）的CeMnO混合氧化物改性的SBA-15负载Ni催化剂对CH/CO比为1的甲烷干重整反应。通过广角XRD、SAXS、N吸附、TPR-H、TEM、UV-vis和拉曼光谱对所得样品进行了表征。用CeMnO对SBA-15进行改性可减小NiO纳米颗粒的尺寸并增强NiO与载体的相互作用。当Ce/Mn = 9时，NiO在大的CeO颗粒表面形成小颗粒和/或与CeO相互作用，形成混合相。在Ni/CeMnO/SBA-15（9:1）催化剂上实现了最佳催化性能（在650℃时，CH和CO转化率分别为51%和69%）。特殊的CeMnO组成（Ce/Mn = 9）也提高了催化剂的稳定性：在24小时稳定性测试中，与未改性催化剂降低30 rel.%相比，CH转化率降低了18 rel.%。Ni/CeMnO/SBA-15（9:1）增强的催化稳定性归因于高浓度的活性过氧（O）和超氧（O）物种，与未改性的Ni-SBA-15催化剂相比，它们显著降低了焦炭量（重量损失2.7%对42.2%）。等摩尔Ce/Mn比或Mn过量改性的Ni-SBA-15性能较差。锰含量最高的Ni/CeMnO/SBA-15（1:4）在整个温度范围内显示出试剂的最低转化率（X(CO)=4 - 36%，X(CH)=8 - 58%）。这一发现可能归因于氧化锰的存在，其在制备阶段由于重新分布而覆盖在Ni颗粒上。
