Boosting propane dehydrogenation over Sn stabilizing dispersed Ptδ+ confined in Silicalite-1 at low temperature

Obtaining highly stable Td‐Co(II) site by coupling hydrothermal method and CO2 introduction for propane dehydrogenation

“…Only one characteristic peak at BE of 781.9 eV assigned to the Co (II) 2 p 3/2 species appears over Co/S‐1‐HTS catalyst during CO 2 ‐PDH process after 1 h reaction (Figure 12A). However, when the CO 2 is absent for PDH, after 1 h reaction, besides the Co (II) 2 p 3/2 peak is observed, another shoulder peak at BE of 778.23 eV is observed correspondingly (Figure 12A), which is assigned to metallic Co species 22,38,57 . Hence, it could be inferred that the reduction of Co (II) to metallic Co species in the PDH process, which further results in the existence of the induction period.…”

“…However, when the CO 2 is absent for PDH, after 1 h reaction, besides the Co (II) 2p 3/2 peak is observed, another shoulder peak at BE of 778.23 eV is observed correspondingly (Figure 12A), which is assigned to metallic Co species. 22,38,57 Hence, it could be inferred that the reduction of Co (II) to metallic Co species in the PDH process, which further results in the existence of the induction period. Therefore, CO 2 is introduced to the reaction system over From the UV-Raman results in Figure S18, two bands at 1387 and 1598 cm À1 are observed over Co/S-1-HTS catalysts over the CO 2 -PDH and PDH processes after 1 h reaction, which could be assigned to the C-H bending vibration of coke species and coke deposition, respectively.…”

“…The transformation of Co 3 O 4 into T d -Co(II) by hydrothermal treatment3.1.1 | Textural and morphological properties of catalystsFirst, combined characterizations including XRD, N 2 adsorption and desorption, ICP and TEM are used to assess the catalyst's basic physicochemical properties. From the XRD characterization results in Figure1A, it could be found that S-1, Co/S-1, and Co/S-1-HTS all show the similar intensity of MFI diffraction peaks, indicating that the hydrothermal treatment does not affect the corresponding MFI structure 37,38. The absence of Co 3 O 4 (PDF#43-1003) or CoO (PDF#48-1719) diffraction peaks in the XRD patterns indicates that the Co species are highly dispersed before and after the hydrothermal process or the Co loading content is below the XRD detection limit.…”

Enhanced PtIn Catalyst via Ce-Assisted Confinement Effect in Propane Dehydrogenation

“…37 Notably, in the Pt 4f spectrum, the positive shift of 0.3 eV for the spent 0.5Pt0.3In(0.3Ce)/SiO 2 and 0.5Pt0.3In(2.0Ce)/SiO 2 catalysts indicates the Ce addition modifies the electronic structure of Pt δ+ active sites. 61,62 Similarly, the In 3d spectrum is deconvoluted into two pairs of Gaussian−Lorentzian peaks, of which the bands at 444.2− 444.6 eV are ascribed to In 0 species and the other band located at 445.9 eV assigned to In 3+ species of spin−orbit doubles. 37,39,63 Interestingly, contrary to the change of the binding energy of Pt 4f, the binding energy of In 0 species of the spent 0.5Pt0.3In(0.3Ce)/SiO 2 downshifted by 0.4 eV, which proved that the introduction of 0.3Ce promoted the formation of the strong electron synergy between Pt and In.…”

Synergistic mechanism of isolated Fe3+ and highly dispersed Ptδ+ over zeolite for boosting propane dehydrogenation

“…to modify the Pt active sites via geometric and electronic effects. [16][17][18][19][20][21][22] In addition, since the catalyst supports play a vital role in affecting the Pt dispersity via metalsupport interaction, correspondingly, different supports including Al 2 O 3 , CeO 2 , SiO 2 , MgAl 2 O 4 , carbon materials, and zeolites have been investigated. 6,[23][24][25] Especially, zeolites have been widely investigated as ideal host materials for supported Pt via zeolite pore confinement effect (metal@zeolite), 15,[26][27][28][29] owing to the well-ordered zeolite framework structures, tunable acidity, and superior thermal stability.…”