The role of sulfur sinks and micro-structured supports on the performance of sulfur-sensitive non-PGM catalysts
The role of sulfur sinks and micro-structured supports on the performance of sulfur-sensitive non-PGM catalysts
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DOI：
10.1016/j.apcata.2021.118201
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发表时间：
2021-05-28
影响因子：
5.5
通讯作者：
Garcia-Garcia, Francisco R.
中科院分区：
文献类型：
--
作者：
Garcia-Vazquez, Miguel;Satir, Doga;Garcia-Garcia, Francisco R.
痕量二氧化硫（即 1-10 ppmV）以及残余甲烷排放的存在会导致典型甲烷减排催化剂的快速失活。因此，硫引起的中毒是残余甲烷减排后处理技术面临的主要挑战。本研究的目的是合成一系列钴和钼催化剂，并评估它们在实际后处理条件下的性能。通过BET、XRD、XPS、TPR、气流下TGA、SEM、EDX和原位DRIFTS等手段对该系列催化剂进行了表征。此外，在类似的反应条件下评估了氧化铝中空纤维负载的 Co100 的性能，并通过 SEM 和 EDX 进行了表征。结果发现，该系列钴、钼催化剂的催化活性依次降低：Co100>Co80Mo20>Co60Mo40。此外，还发现其他两种催化剂（即Co25Mo75和Mo100）由于缺乏高活性的Co3+物种而在450℃时失活。在活性催化剂中，Co100和Co80Mo20经历了初始活化，然后逐渐失活，而Co60Mo40在活化和失活之间经历了1小时的间隔，具有稳定的甲烷转化水平。 Co60Mo40 活性氧化钴 (II,III) 相中毒的延迟归因于该催化剂中存在的钴钼氧化物 (即 44 wt%) 的硫沉降特性。最终，负载在氧化铝中空纤维上的Co100实现了单位质量催化剂的最高甲烷转化率，并且其性能在2.5小时内保持稳定。高活性归因于载体的几何形状提供的大表面积，而较高的抗硫中毒性归因于氧化铝的硫沉降特性，这延迟了活性相的中毒。
The presence of traces of sulfur dioxide (i.e. 1-10 ppmV) alongside residual methane emissions induces the rapid deactivation of typical methane abatement catalysts. As a result, sulfur-induced poisoning is the main challenge faced by after-treatment technologies for residual methane abatement. The aim of this study was to synthesise a series of cobalt and molybdenum catalysts and assess their performance under realistic after-treatment conditions. The series of catalysts was characterised by BET, XRD, XPS, TPR, TGA under air flow, SEM, EDX and in situ DRIFTS. In addition, the performance of Co100 supported on an alumina hollow fibre was assessed under similar reaction conditions and characterised by SEM and EDX. It was found that the catalytic activity of the series of cobalt and molybdenum catalysts decreased in the following order: Co100 > Co80Mo20 > Co60Mo40. In addition, it was discovered that the other two catalysts (i.e. Co25Mo75 and Mo100) were inactive at 450 degrees C due to the lack of highly active Co3+ species. Among the active catalysts, Co100 and Co80Mo20 experienced an initial activation followed by a gradual deactivation whereas Co60Mo40 experienced a 1 h interval with stable methane conversion levels in between the activation and deactivation. The delay in poisoning of the active cobalt (II,III) oxide phase of Co60Mo40 was attributed to the sulfur sink-properties of the cobalt molybdenum oxide present in this catalyst (i.e. 44 wt%). Finally, Co100 supported on an alumina hollow fibre achieved the highest methane conversion per unit mass of catalyst and its performance was stable for a duration of 2.5 h. The high activity was attributed to the large surface area provided by the geometry of the support while the higher resistance to sulfur poisoning was credited to the sulfur sink-properties of the alumina, which delayed the poisoning of the active phase.