Catalyst deactivation by coking is one major problem for propane dehydrogenation (PDH). To develop catalysts with high resistance to coke, the analysis of coke becomes essential. In this work, an analysis procedure is proposed and validated to acquire the detailed locations and compositions of the coke formed on an as-synthesized Pt–Sn/Al2O3 catalyst. This procedure combines high-resolution transmission electron microscopy (HRTEM), FT-IR, Raman, thermogravimetric analysis (TG), and pyrolysis GC-MS; with this procedure, the systematic and quantitative analysis of coke can be achieved. The results show that the coke is located on the metal, in the vicinity of the metal, and on the support. Besides, aliphatics, aromatics, and pregraphite cokes are identified, and they account for 69.0, 4.4, and 26.6 wt %, respectively. Finally, an in situ DRIFT study is performed, and the results show that the aliphatic coke can be transformed into the aromatic coke and this transformation is related to the deep dehydrogenation reactions.

The ability to generate nanoscale zeolites and direct their assembly into hierarchical structures offers a promising way to maximize their diffusion-dependent catalytic performance. Herein, we report an orientated assembly strategy to construct hierarchical architectures of silicoaluminophosphates (SAPOs) by using prefabricated nanocrystallites as a precursor. Such a synthesis is enabled by interrupting the dry gel conversion process to prepare nanocrystallites, as crystal growth is shown to proceed predominantly by particle attachment. The orientation of assembly can be controlled to form either a three-dimensional, spongelike morphology or a two-dimensional “house-of-cards” structure, by modifying the additives. Structures with a high degree of control over crystal size, shape, architecture, pore network, and acidic properties are achieved. This versatile technique avoids the more tedious and expensive templating routes that have been proposed previously. The catalytic performance for the hydroisomerization of n-heptane was evaluated for a series of Pt-supported catalysts, and a record isomer yield (79%) was attained for a catalyst with spongelike architecture. The hierarchical architecture influences isomer selectivity for two reasons: expanding the intrinsic-reaction-controlled regime to be able to work at higher temperatures or conversion levels, and enhancing mass transport to reduce cracking of dibranched isomers. Such an acidity–diffusivity interplay indicates that strong acidity favors isomerization operating at temperatures away from the diffusion-limited regime, while crystal size and pore connectivity are key factors for enhancing diffusion. The proposed materials offer tremendous opportunities to realize hierarchical catalyst designs that work under optimal operating conditions.

A heterojunction-redox catalysis strategy is proposed for fabricating a dual-functional catalyst/adsorbent to realize integration of high-temperature CO2 capture and in situ conversion.

Supporting Information and the ORCID identification number(s) for the author(s) of this article can be found under: https://doi.

Interleukin-33 (IL-33) is a member of the interleukin-1 (IL-1) cytokine family and an extracellular ligand for the orphan IL-1 receptor ST2. Accumulated evidence shows that the IL-33/ST2 axis plays a crucial role in the pathogenesis of central nervous system (CNS) diseases and injury, including traumatic brain injury (TBI). However, the roles and molecular mechanisms of the IL-33/ST2 axis after TBI remain poorly understood. In this study, we investigated the role of IL-33/ST2 signaling in mouse TBI-induced brain edema and neurobehavioral deficits, and further exploited underlying mechanisms, using salubrinal (SAL), the endoplasmic reticulum (ER) stress inhibitor and anti-ST2L. The increase in IL-33 level and the decrease in ST2L level at injured cortex were first observed at 24 h post-TBI. By immunofluorescent double-labeled staining, IL-33 co-localized in GFAP-positive astrocytes, and Olig-2-positive oligodendrocytes, and predominantly presented in their nucleus. Additionally, TBI-induced brain water content, motor function outcome, and spatial learning and memory deficits were alleviated by IL-33 treatment. Moreover, IL-33 and SAL alone, or their combination prevented TBI-induced the increase of IL-1β and TNF-α levels, suppressed the up-regulation of ER stress, apoptosis and autophagy after TBI. However, anti-ST2L treatment could significantly invert the above effects of IL-33. Together, these data demonstrate that IL-33/ST2 signaling mitigates TBI-induced brain edema, motor function outcome, spatial learning and memory deficits, at least in part, by a mechanism involving suppressing autophagy, ER stress, apoptosis and neuroinflammation.

No abstract

A versatile pore network model is used to study deactivation by coking in a single catalyst particle. This approach allows to gain detailed insights into the progression of deactivation from active site, to pore, and to particle-providing valuable information for catalyst design. The model is applied to investigate deactivation by coking during propane dehydrogenation in a Pt-Sn/Al 2 O 3 catalyst particle. We find that the deactivation process can be separated into two stages when there exist severe diffusion limitation and pore blockage, and the toxicity of coke formed in the later stage is much stronger than of coke formed in the early stage. The reaction temperature and composition change the coking rate and apparent reaction rate, informed by the kinetics, but, remarkably, they do not change the capacity for a catalyst particle to accommodate coke. Conversely, the pore network structure significantly affects the capacity to contain coke.

No abstract