Two separate synthesis procedures were applied to alter the location of Cobalt (Co) in bimetallic silica (SiO₂) microsphere catalyst with Nickel (Ni) as the second active metal. Co was either encapsulated with simultaneous Ni addition inside core structure (Ni,Co/SiO₂) or impregnated on the shell following initial encapsulation of Ni inside the microsphere (Ni/SiO₂&Co). Catalysts were tested in dry reforming of methane (DRM) reaction at 750 °C with a feed mixture of CH₄:CO₂:N₂ = 1:1:1. Reactions were performed in a stainless steel temperature-controlled tube reactor. Results indicated the highest activity values with 4Ni-1Co ratio in catalyst structure and Co impregnated on catalyst structure revealed higher activity for all loadings compared to Ni,Co/SiO₂ catalysts. CH₄ and CO₂ conversions for 3 h of reaction were obtained as 87 and 94%, and H₂/CO ratio was determined as 0.84 in the presence of Ni/SiO₂&Co catalyst with 4Ni-1Co loading. Coke formation was not detected for the catalyst with 4Ni-1Co loading and the highest coke amount was 2% among all catalysts. Time on stream test in the presence of Ni/SiO₂&Co catalyst with 4Ni-1Co loading was conducted for 12 h in identical conditions, and results revealed a stable activity with conversions equal to 3 h of reaction. Coke suppression during DRM reaction was attributed to microsphere structure, Co presence and SiC formation. SiC formation was introduced as a unique situation emanated as a result of the reaction between SiO₂ and C.

中文翻译：

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Ni，Co / SiO 2和Ni / SiO 2，Co双金属微球催化剂在甲烷干重整中显示出高活性和稳定性

应用了两个单独的合成程序，以镍（Ni）为第二活性金属，改变了钴（Co）在双金属二氧化硅（SiO ₂）微球催化剂中的位置。Co既可以在芯结构内部同时添加Ni来封装（Ni，Co / SiO ₂），也可以在将Ni初始封装在微球内部之后（Ni / SiO ₂＆Co）浸渍在壳上。在CH ₄：CO ₂：N ₂进料混合物的条件下，在750°C的甲烷干重整（DRM）反应中测试了催化剂 = 1：1：1。反应在不锈钢温控管式反应器中进行。结果表明，与Ni，Co / SiO ₂催化剂相比，催化剂结构中4Ni-1Co比的最高活性值和浸渍在催化剂结构中的Co在所有负载下均显示出更高的活性。反应3小时的CH ₄和CO ₂转化率分别为87％和94％，在Ni / SiO ₂＆Co催化剂负载4Ni-1Co的条件下，H ₂ / CO比确定为0.84 。对于负载为4Ni-1Co的催化剂，未检测到焦炭形成，并且在所有催化剂中，最高焦炭量为2％。Ni / SiO ₂存在下的运行时间测试在相同条件下，负载4Ni-1Co的＆Co催化剂进行了12 h，结果表明其活性稳定，转化率等于3 h反应。DRM反应过程中的焦炭抑制作用归因于微球结构，Co的存在和SiC的形成。由于SiO ₂和C之间的反应而引入了SiC形成，这是一种独特的情况。