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Stronger interaction created by B2O3 modification mitigates the oxygen reactivity of FeOx, promoting styrene selectivity in the oxidative dehydrogenation of ethylbenzene.

Styrene and benzaldehyde are manufactured by energy-intensive direct dehydrogenation and an intermittent liquid chlorine oxidation batch process, respectively. The coproduction of styrene and benzaldehyde through selective oxidation of ethylbenzene is an environmentally friendly and economically feasible alternative. However, it is hard to control the selectivity for styrene or benzaldehyde as a result of deep oxidation reactions. Here, we report an efficient selective oxidation catalyst, boron nitride-supported monomeric MoOx (MoOx/BN), over which styrene and benzaldehyde can be selectively coproduced. Structure characterization and catalytic evaluation reveal that the MoOx/BN catalyst is conducive to the generation of benzaldehyde and less formation of COx than for monomeric MoOx supported on inert silica. Based on the kinetic analysis, over MoOx/BN catalyst, styrene is the primary product and benzaldehyde is the major by-product in the subsequent oxidation reaction. The boron hydroxy groups of the MoOx/BN catalyst are involved in the reaction network, which could regulate the reaction behavior of monomeric MoOx species; thus the reaction generates more benzaldehyde.

Metal-free boron- and carbon-based catalysts have shown both great fundamental and practical value in oxidative dehydrogenation (ODH) of light alkanes. In particular, boron-based catalysts show a superior selectivity toward olefins, excellent stability and atom-economy to valuable carbon-based products by minimizing CO2 emission, which are highly promising in future industrialization. The carbonaceous catalysts also exhibited impressive behavior in the ODH of light alkanes helped along by surface oxygen-containing functional groups. This review surveyed and compared the preparation methods of the boron- and carbon-based catalysts and their characterization, their performance in the ODH of light alkanes, and the mechanistic issues of the ODH including the identification of the possible active sites and the exploration of the underlying mechanisms. We discussed different boron-based materials and established versatile methodologies for the investigation of active sites and reaction mechanisms. We also elaborated on the similarities and differences in catalytic and kinetic behaviors, and reaction mechanisms between boron- and carbon-based metal-free materials. A perspective of the potential issues of metal-free ODH catalytic systems in terms of their rational design and their synergy with reactor engineering was sketched.

In heterogeneous catalysis, carbon deposition on catalysts during the operating conditions of a reaction can be a disastrous problem, especially when using widely adopted acidic alumina as a support. Designing anti-coke catalysts, with the aim of improving the coking tolerance, and achieving a high catalytic reactivity is highly desirable but always remains challenging. Here, the excellent anti-coke capacity of a laboratory-made catalyst of alumina nanosheets supporting Pt–Sn for isobutane dehydrogenation is reported. The prepared alumina nanosheets showed abundant defect sites and less acidity compared to the commercial product. The results of the CO-DRIFT spectra showed that the electron density of platinum was increased with the stronger electronic interactions between platinum and tin on the alumina nanosheets. The alumina nanosheet supported Pt–Sn catalyst showed an improved stability, selectivity and activity when compared to previously studied alumina supported Pt-based catalysts reported in the literature, under the dehydrogenation of isobutane reaction conditions of over 24 h at 560 °C. The detailed characterization confirmed that coke species were mainly located on the surface of the alumina nanosheets instead of on the metal particles or in the vicinity of the metal particles, thus ensuring good exposure of active sites. The coke species contained more aliphatics with a higher degree of disorder, which facilitated the elimination of coke during the regeneration process. This study demonstrated that rational design of the support structure could be an efficient strategy to govern the coke behaviors of supported catalysts, and thus could be used to provide guidelines for future catalyst design with high reactivity and stability for a variety of catalytic applications.

Ordered macroporous materials with rapid mass transport and enhanced active site accessibility are essential for achieving improved catalytic activity. In this study, boron phosphate crystals with a three-dimensionally interconnected ordered macroporous structure and a robust framework were fabricated and used as stable and selective catalysts in the oxidative dehydrogenation (ODH) of propane. Due to the improved mass diffusion and higher number of exposed active sites in the ordered macroporous structure, the catalyst exhibited a remarkable olefin productivity of ~16 golefin gcat−1 h−1, which is up to 2–100 times higher than that of ODH catalysts reported to date. The selectivity for olefins was 91.5% (propene: 82.5%, ethene: 9.0%) at 515 °C, with a propane conversion of 14.3%. At the same time, the selectivity for the unwanted deep-oxidized CO2 product remained less than 1.0%. The tri-coordinated surface boron species were identified as the active catalytic sites for the ODH of propane. This study provides a route for preparing a new type of metal-free catalyst with stable structure against oxidation and remarkable catalytic activity, which may represent a potential candidate to promote the industrialization of the ODH process.

Supported gold catalysts show high activity toward CO oxidation, and the nature of the support significantly affects the catalytic activity. Herein, serial Ni doping of thin porous Al2O3 nanosheets was performed via a precipitation-hydrothermal method by varying the amount of Ni during the precipitation step. The prepared nanosheets were subsequently used as supports for the deposition of Au nanoparticles (NPs). The obtained Au/NixAl catalysts were studied in the context of CO oxidation to determine the effect of Ni doping on the supports. Enhanced catalytic performances were obtained for the Au/NixAl catalysts compared with those of the Au supported on bare Al2O3. The Ni content and pretreatment atmosphere were both shown to influence the catalytic activity. Pretreatment under a reducing atmosphere was beneficial for improving catalytic activity. The highest activity was observed for the catalysts with a Ni/Al molar ratio of 0.05, achieving complete CO conversion at 20 deg;C with a gold loading of 1 wt%. The in-situ FTIR results showed that the introduction of Ni strengthened CO adsorption on the Au NPs. The H2-TPR and O2-TPD results indicated that the introduction of Ni produced new oxygen vacancies and allowed the oxygen molecules to be adsorbed and activated more easily. The improved catalytic performance after doping Ni was attributed to the smaller size of the Au NPs and more active oxygen species.

Direct catalytic propane dehydrogenation (PDH) to obtain propylene is a more economical and environmentally friendly route for propylene production. In particular, alumina-supported Cr2O3 catalysts can have better potential applications if the acidic properties could be tuned. Herein, a series of rod-shaped porous alumina were prepared through a hydrothermal route, followed by calcination. It was found that the acidity of the synthesized alumina was generally lower than that of the commercial alumina and could be adjusted well by varying the calcination temperature. Such alumina materials were used as supports for active Cr2O3, and the obtained catalysts could enhance the resistance to coke formation associated with similar activity in PDH reaction compared to the commercial alumina. The amount of coke deposited on a self-made catalyst (Cr-Al-800) was 3.6%, which was much lower than that deposited on the reference catalyst (15.7%). The lower acidity of the catalyst inhibited the side reactions and coke formation during the PDH process, which was beneficial for its high activity and superior anti-coking properties.

Background Autosomal recessive congenital ichthyosis (ARCI) is a group of genetically heterogeneous diseases. Mutations in transglutaminase (TGase) 1 gene (TGM1, OMIM 190195) have been implicated in ARCI. However, little is known about TGM1 mutations in the Chinese population, and no functional studies have investigated the biological effect of mutant TGM1 on human epidermal keratinocytes (HaCaT) cells. Objectives To identify the pathogenic mutations of TGM1 gene in two Chinese siblings with ARCI and gain insight into functional consequences of these mutations. Methods Fifteen exons and flanking splice sites of TGM1 gene were amplified by polymerase chain reaction and then underwent bidirectional Sanger sequencing. The HaCaT cells were transfected with lentiviral vectors, which overexpressed either wild-type or mutant TGM1 cDNAs with deleted homeodomain. Cell proliferation and cell cycle progression were detected. The expression of cyclin D1, cyclin B1, CDK4, TGM1, K10, involucrin, and filaggrin proteins were investigated by Western blot analysis. Results We found two compound heterozygous missense mutations (c.515C>T, R143C in exon 3 and c.759C>T, S212F in exon 4) in both siblings. HaCaT cells transfected with mutant TGM1 cDNAs displayed a lower growth rate and delayed S phase while overexpression of wild-type TGM1 cDNAs led to accelerated growth. HaCaT cells transfected with mutant TGM1 cDNAs displayed lower expression of differentiation markers such as involucrin and filaggrin. Our findings suggest that the compound heterozygous missense (c.515C>T, R143C) mutations in exon 3 and missense (c.759C>T, S212F) mutations in exon 4 result in the phenotype of ARCI. TGM1 mutations can suppress keratinocyte growth and cornified cell envelope formation.