Catalyst deactivation by carbon formation during CO hydrogenation to hydrocarbons on mesoporous Co3O4

Stabilized ordered-mesoporous Co3O4 structures using Al pillar for the superior CO hydrogenation activity to hydrocarbons

“…However, the moderate metallic cobalt surface areas were observed on the Mn/meso-Co 3 O 4 and Si/meso-Co 3 O 4 with values of 10.7 and 14.8 m 2 /g Co , respectively. These differences in surface areas measured by BET and H 2 chemisorption were mainly attributed to the partial meso-structural collapse during reduction treatment at 400 • C, especially on the meso-Co 3 O 4 as previously reported in our previous work [24]. It may also be due to the pore blockage by pillaring materials such as Mn and Si metal oxides.…”

“…The reduction patterns of Co 3 O 4 particles have been generally known to proceed in two-stage reductions as follows: spinel structure Co 3 O 4 → CoO → metallic cobalt (Co 0 ) [4,37,38]. On the metal oxide pillared meso-Co 3 O 4 , the first characteristic reduction peak below 400 • C can be assigned to the reduction of Co 3 O 4 to CoO, and the second peak below 600 • C to the reduction of CoO to metallic cobalt [4,24]. On the meso-Co 3 O 4 , the maximum reduction peaks were observed at 316 and 438 • C, in accordance with the typical two step reduction behavior of Co 3 O 4 , and a shoulder peak was observed at 363 • C possibly due to the presence of aggregated cobalt particles during a synthesis step of meso-Co 3 O 4 [24].…”

“…On the metal oxide pillared meso-Co 3 O 4 , the first characteristic reduction peak below 400 • C can be assigned to the reduction of Co 3 O 4 to CoO, and the second peak below 600 • C to the reduction of CoO to metallic cobalt [4,24]. On the meso-Co 3 O 4 , the maximum reduction peaks were observed at 316 and 438 • C, in accordance with the typical two step reduction behavior of Co 3 O 4 , and a shoulder peak was observed at 363 • C possibly due to the presence of aggregated cobalt particles during a synthesis step of meso-Co 3 O 4 [24]. On the Mn/mesoCo 3 O 4 and Si/meso-Co 3 O 4 , two distinctive reduction peaks were also observed at different temperatures of 357 and 414 • C on the Si/meso-Co 3 O 4 and they shifted to higher temperature regions of 377 and 465 • C on the Mn/meso-Co 3 O 4 .…”

“…The intensive C1s peaks were observed on all the used catalysts (Fig. S5), however, the deconvoluted peak intensity at the BE of 284.6 eV (Table S1), which can be assigned to graphite or C C carbons [29,58], was found to be larger on the mesoCo 3 O 4 by forming an encapsulated amorphous heavy hydrocarbons on the cobalt particles [24] compared to the Al/meso-Co 3 O 4 .…”

“…In the present study, we focused on designing a stable orderedmesoporous Co 3 O 4 to enhance catalytic stability and activity even under hydrogen-rich environment by simply incorporating metal oxide pillars such as Al, Mn and Si oxides inside pores, since we had observed the easy collapse of unmodified mesoporous Co 3 O 4 structures under the FTS reaction in our previous work [24]. The ordered mesoporous Co 3 O 4 was previously synthesized using nano-replication and the selected metal oxide pillaring materials was subsequently added through simple wet impregnation.…”